A Protocol for Highway Managers and Bridge Owners - Transport ...

Prevention of Strikes on Bridges over HighwaysA Protocol for Highway Managers and Bridge OwnersA Protocol forHighway Managers and Bridge OwnersPurpose:Scope:To give guidance and advice to highway managers and bridge owners to minimisestrikes on bridges that span public highways.• The guidance is intended for all highway authorities and for all local authorities,transport authorities and other public authorities and private companieswho own bridges over public highways.• Additionally, the advice is pertinent to private landowners who have accessways under bridges carrying railways or public highways.• The guidance applies to all bridges, with and without headroom signs, overvehicular highways.ContentsPage1.0 Introduction 22.0 Highway repairs under bridges; bridgework over highways 33.0 Signing of restricted headroom at bridges 54.0 Maintenance of signs 115.0 Other protection techniques 126.0 Distractions from advertising 127.0 Lighting in the vicinity of railways and under bridges 138.0 Temporary works and working practices 139.0 Joint working with Network Rail, London Underground Ltd 14and other bridge owners10.0 Other important considerations 1511.0 Action to take when informed of a bridge strike 1612.0 Other useful documents 17Bibliography 19APPENDIX A: Surfacing activities under bridges over highways 21APPENDIX B: Additional options for protecting against bridge strikes 23APPENDIX C: Sample sign inspection report form 26APPENDIX D: Examples of sites where signing could be improved 30APPENDIX E: TRL - bridge audit check sheet 32Registration, feedback and contacts 361

Prevention of Strikes on Bridges over HighwaysA Protocol for Highway Managers and Bridge Owners1.0 Introduction1.1 There is no legislation limiting the height of vehicles which can travel on the roadsin the UK or requiring drivers to notify or seek approval to travel in respect of anythreshold in vehicle height. Because of this, there are a number of issues that need tobe clearly stated, understood and addressed where roads go under bridges. This isparticularly the case for the prevention of bridge strikes, the consequences of whichare always costly and which can be fatal for both the driver of the vehicle and thepeople on or under the bridge in passing rail or road traffic.1.2 The following protocol seeks to identify these issues and recommend practices andprocedures which, if followed, will contribute towards the prevention of bridge strikes,thereby ensuring greater safety for all travellers.1.3 Whilst there is no one panacea to the problems of bridge strikes, it is important toincrease driver understanding and awareness if any success is to be achieved. Forthis to happen, one vital ingredient is for a consistency of approach to signing androad maintenance at bridges to be applied across the country.1.4 Bridge strikes are a particular problem for Network Rail who incur high costs fromdisruptions to train movements and structural repairs from the many impacts annuallyon their bridges, and for whom a derailment due to misaligned track is an ever presentdanger. There have also been instances of lorries, or their loads, being overturnedonto vehicles or pedestrians in adjacent lanes/footways at bridges heavily skewed tothe road.1.5 The standard minimum clearance to be provided over every part of the carriageway ofa public highway is 16’-6” (5.03m). All bridges with a headroom of less than this shouldbe signed giving an appropriate safety margin identifying the (maximum) safe vehicleheight which can be accommodated. It is generally accepted that highway authoritieswill install and maintain this signing at least to minimum requirements. Bridges withheadroom beneath the signing threshold are generally referred to in this protocol as‘low bridges’.2

Prevention of Strikes on Bridges over HighwaysA Protocol for Highway Managers and Bridge Owners1.6 Highway authorities also have major problemsat higher unsigned bridges with many hit andrun incidents where concrete is damaged orbeams distorted which are not reported atthe time. Lightweight structures such asfootbridges or pipe gantries are particularlyvulnerable where drivers are careless aboutthe height of their loads and, as a result ofsuch carelessness, several have beendislodged or brought down over the yearsacross the country. Such hit and runincidents are also a risk to rail bridges.1.7 CSS’ Bridges Group has therefore producedthis protocol in collaboration with NetworkRail and the Department for Transport andstrongly urges all highway authorities andbridge owners to adopt the practicesrecommended therein. In this way, aconsistent approach can be applied acrossthe country so as to increase driverunderstanding and awareness.1.8 Proactive liaison between interested parties will be essential to minimising the riskwhich bridge strikes bring to both the transport industry and public safety.2.0 Highway repairs under bridges; bridgeworkover highwaysHighway repairs under bridges2.1 No surfacing works including full depth reconstruction, plane off and inlay, surfacedressing or overlay should be undertaken in the vicinity of any bridge without thedesigner first discussing the proposal and its implications with both the highwayauthority’s bridge engineer and, where different, the bridge owner and obtaining theiragreement. This is due to the potential for uncontrolled reductions in headroomunder the bridge to occur leading to an increase in incidences of bridge strikes. Thisapplies to all bridges, those with restricted (signed) headrooms and those where theactual minimum headroom equals or exceeds 16’-6” (5.03m), the standard minimummaintained headroom.2.2 Obligations to consult and serve notice under the New Roads and Street Works Actmust also be followed for such works.3

Prevention of Strikes on Bridges over HighwaysA Protocol for Highway Managers and Bridge Owners2.3 In any such situation, there must always be a presumption against raising surfacinglevels and so reducing headroom. Occasions when this might be allowed are strictlylimited and must be controlled by the highway authority bridge engineer and agreedwith Network Rail or other bridge owners. Network Rail do, at certain sites, have alegal obligation to provide a minimum clearance and this must not be compromised byany proposal without formal agreement from all involved parties. A guidance note onthe issue of height changes is given in Appendix A.2.4 There are potentially very serious implications arising from possible changes inheadroom as a result of surfacing work. Checking of the available clearance underthe bridge must therefore be carried out both before and after surfacing, the latterbeing before traffic is allowed back on the carriageway, to ensure compliance withthe agreed design. If an unsanctioned, unprotected reduction in clearance hasoccurred, immediate corrective action must be taken before allowing traffic access.2.5 If there is a change in headroom agreed byboth parties, especially one which reducesavailable headroom on signed bridges, allrelated signs at, on and in advance of thebridge, and also on related directional signs,must be changed to indicate the new safevehicle height available under the bridgebefore traffic is allowed access. It is theresponsibility of the highway authority toensure this happens. Additional non-standard signs, as shown, could be provided atthe site for up to six months to draw drivers attention to the change but will needauthorisation from the Department for Transport.2.6 Reductions in clearance under unsigned bridges must at no time reduce the availableminimum headroom below that specified in Chapter 6 of TD 27/05 in DMRB 1 for themaintained headroom for the type of bridge involved. Also see Appendix A section A.3.2.7 If work has been undertaken which results in improved headroom, signing must beamended or removed, as appropriate, as soon as possible and again it is theresponsibility of the highway authority to ensure this happens.Bridgework over highways2.8 The requirements for consultation and agreement must also be applied to any changesto or planned protection of the structure of a bridge spanning over the highwayproposed by the bridge owner. Signing must be checked and corrected beforeallowing traffic to reuse the road and drivers warned of any lowering of headroom.Bridge owners must meet the highway authority’s costs in carrying out this work.41Design Manual for Roads and Bridges (DMRB) Volume 6 ‘Road Geometry’ Section 1, Part 2, TD 27/05 ‘Cross Sections andHeadrooms’, (February 2005) London: TSO for Highways Agency

Prevention of Strikes on Bridges over HighwaysA Protocol for Highway Managers and Bridge Owners3.0 Signing of restricted headroom at bridgesMeasuring headroom and determining signed height3.1 The clearance under bridges spanning public roads in the UK, below which low bridgesigning is required, is 16’-6” (5.03m). All bridges with a headroom of less than this, atany point over a carriageway, should be signed in accordance with the guidancegiven in Chapter 4 of the Traffic Signs Manual (TSM) 2 , section 7. This will, in allsituations, allow a minimum safety margin of 3” or 0.1m (these are not equivalentvalues but are each determined in accordance with the measurement guidelines).Additional guidance on the use of road markings to guide high vehicles at arch bridgesis given in Chapter 5 of TSM 3 . It is important to note that signing only relates to theheadroom over the carriageway. Footways and verges are not included and so relatedchevrons or hazard markings must not extend beyond the limits of the carriageway.3.2 The signed height at low bridges is referred to in this document as the (maximum)safe vehicle height, as it represents the maximum height of vehicle/load combinationwhich can pass safely on the carriageway under the bridge without impacting on it,allowing for vehicle (suspension) bounce, and safety tolerances. This is the heightwhich will usually be given to hauliers. Details of the actual measured minimumheadroom available and the wider headroom envelope at a bridge are for the use ofthe highway authority in determining respectively the maximum safe vehicle heightand the potential for routing high vehicles around the network. High vehicles arethose which cannot pass safely under a bridge of 16'-6” (5.03m) minimumheadroom and so are those with vehicle/load combination greater than 16’-3” (4.95m)high allowing for the minimum safety margin.3.3 It is generally accepted that highway authorities will install and maintain signing at lowbridges at least to minimum requirements and for this they need to measure andrecord the actual headroom under bridges spanning their carriageways. This shouldbe determined by a survey of the headroom at least at both elevations of the bridgeand additionally at any obvious low spots on the soffit. The height should bemeasured, and the available headroom indicated, as specified in TSM 4 paragraph 7.7.Paragraphs 7.8 and 7.9 give guidance on use of metric as well as imperial units ofmeasurement. Allowance for the bridging effects of longer vehicles must be made asdescribed in paragraph 3.7 overleaf.3.4 The exercise in paragraph 3.3 should be carried out for all sites so that the safevehicle height can be determined where any bridge or gantry spans the road. This isto enable highway authorities to:(a) correctly sign bridges with less than 16’-6” (5.03m) minimum headroomanywhere over the carriageway and(b) advise hauliers requesting details of safe vehicle heights to plan the movementsof high loads (ie, those higher than 16’-3” (4.95m)).2 & 4Traffic Signs Manual Chapter 4 ‘Warning Signs’ (2004) London: TSO for DfT et al.3Traffic Signs Manual Chapter 5 ‘Road Markings’ (2003) London: TSO for DfT et al.5

Prevention of Strikes on Bridges over HighwaysA Protocol for Highway Managers and Bridge Owners3.5 Remeasures should be taken by the highway authority:(a) before and after any proposed surfacing work (see paragraphs 2.3 and 2.4).(b) when a highway inspector or bridge owner reports evidence of a possiblechange in surfacing or other circumstance having occurred which has notbeen recorded/measured.(c) where there is evidence of a reported impact on the bridge. In this regard itis important the highway authority is formally notified by bridge owners ofany strikes on their bridges.(d) following any replacement, reconstruction or significant work by NetworkRail or other bridge owner to the bridge superstructure or the provision ofcollision protection beams.(e) at the time of every principal bridge inspection (must be organised by thoseundertaking the inspection).(f) every six years for rail over road bridges (programmed and carried out bythe highway authority) to equate to Network Rail’s cycle of inspection.In this regard a highway authority should clearly define and make known who within itsstaff structure is responsible for receiving information and taking the necessary action.3.6 Any measured reduction in the clearance below the minimum 3” safety margin mustbe corrected immediately by planing and resurfacing or re-signing. If the safety marginincreases to 6” or more, a similar change to signing should be planned at the earliestpossible date. Although this latter scenario is not unsafe, this is to conform to theregulations and avoid bringing the national signing regime into disrepute.3.7 Measurements of actual headroom should be taken vertically using a calibratedmeasuring stick. They should be taken at least on both channels and centre-line oneach elevation and at any other pinch point. Additionally, care should be taken toallow for vehicles of the maximum length permitted by the Construction and UseRegulations and Authorised Weight Regulation by adjusting the calculation for thesigned safe vehicle height to allow for the bridging effect of long vehicles. This isparticularly important where the road dips or hogs sharply or is on a curvingalignment under the bridge. Advice on how to cater for these situations is given inChapter 6 of TD27/05 5 . It is also important to check the implications of the heightof abnormal loads and especially for the increased bridging effect of longer abnormalloads when processing movement notifications.3.8 It is a requirement that heights must be shown in imperial dimensions and may additionallybe shown in metric units. They must not be displayed in metric units alone. It is importanthowever, given the volume of foreign freight traffic in the country, that all signing upgradeschemes include for dual signing. Consideration should also be given to implementing achange to include metric signing at bridges on routes to and from ports or industrialparks where there is a significant concentration of HGV traffic from the rest of Europe.65TD 27/05 ‘Cross Sections and Headrooms’ in DMRB Volume 6 ‘Road Geometry’ Section 1, Part 2, (February 2005) London:TSO for Highways Agency

Prevention of Strikes on Bridges over HighwaysA Protocol for Highway Managers and Bridge OwnersSigning system3.9 Paragraph 7.5 of TSM 6 advises that signs and markings for low bridges, including hazardmarkings, must be correctly installed and maintained to a high standard. For non-archbridges, the guidance in TSM 7 paragraphs 7.12 – 7.15 should be followed, and paragraphs7.17 – 7.19 for arch bridges. In addition to the use of signs at, or immediately before, lowbridges, and the use of black and yellow striped hazard markings to make the bridgemore conspicuous, the guidance covers other signing to give advance warning.Paragraph 7.10 gives details on the provision of planned diversion signing which isparticularly relevant where a structure has a history of repeated strikes.3.10 There are two types of signs, advisory (triangular), whichcan be used at any bridge, and mandatory (roundels) whereuse is limited to flat soffit bridges. Until 1994 the use ofmandatory height limit signs rather than warning trianglesfor non-arch bridges had to be backed by a specific trafficregulation order. Since the introduction of the Traffic SignsRegulations and General Directions 1994 this is no longernecessary as it is an offence (under the Road Traffic Act1988) to fail to comply with a height limit roundel placed toindicate a physical height restriction, without the need for asupporting order. This facilitates easier installation of thesigns and related prosecution of drivers who ignore them.3.11 All highway authorities should be programming to changeadvisory signs for flat deck soffit bridges to mandatory signsas part of a general upgrade and must ensure that any plannedsigning scheme in the vicinity of a low bridge embraces thischange. Sign changes at bridges that are often subjected tobridge strikes should be programmed early. See section 9.0 about joint workingwith Network Rail and other bridge owners.3.12 The signs should be supplemented with appropriate reflectorised hazard markings.Guidance is given in TSM 8 paragraph 7.5, 7.15, 7.19, 7.21 and 7.22.3.13 Detailed guidance on the positioning of mandatory signs is given in TSM 9 paragraph 7.13and advice on the location of warning signs in paragraph 7.14.3.14 Whilst the absolute minimum requirements for signing low bridges would probablyrequire signs only at and/or on the bridge, depending upon the sign status, andincluding the relevant hazard markings, it is also essential that adequate advancewarning of a height restriction is given to drivers. This is to avoid them arriving at thesite in the first place, so avoiding abortive travel or them being tempted to driveunder the bridge. Therefore, signing at the last practical turning point/junction inadvance of the bridge should also be provided.6, 7, 8 & 9Traffic Signs Manual Chapter 4 ‘Warning Signs’ (2004) London: TSO for DfT et al.7

Prevention of Strikes on Bridges over HighwaysA Protocol for Highway Managers and Bridge Owners3.15 Signs further away from the last junction should also be provided to afford driversthe earliest opportunity to choose a different route.3.16 From the above, the recommended system forsigning a low bridge to minimise the risk of bridgestrikes is therefore as follows:(a) Signs attached to each elevation of the bridgeaccompanied by appropriate reflectorisedhazard markings covering the width ofcarriageway to which the limit applies.(b) Post mounted signs in advance of the bridge oneach approach to the bridge. The distance fromthe bridge should be determined in accordancewith TSM 9 Paragraph 7.14. However, mandatorysigns must be located to avoid restrictingaccess to any adjacent entrance.(c) Advance signs advising of the restriction andthe distance to it at the last junction on eachapproach to the bridge and on each leg of thatjunction.(d) Advance signing at the nearest major junctionand on the related direction flag signs.Advance signing should make sense to driversunfamiliar with the area. Positive direction signsfor lorries (white on black format) to high usesites are also a useful aid.3.17 Reference should be made to TSM 9 paragraphs 7.5to 7.22 for details of the signing and hazardmarkings appropriate for different forms ofstructure and type of restriction.9Traffic Signs Manual Chapter 4 ‘Warning Signs’ (2004) London: TSO for DfT et al.8

Prevention of Strikes on Bridges over HighwaysA Protocol for Highway Managers and Bridge Owners3.18 The signing of bridges with restricted headroommust cover the whole carriageway. On archbridges, chord markings (which should always bereflectorised) indicating the extent of the signedwidth should be provided. Where a single chorddoes not cover the whole carriageway the sideWhite lines in carriageway missingchord(s) should also be signed. However, it is theminimum clearance of the centre chord, generally 10' or 3m wide, which is thegoverning height for any advance signing. The corresponding width of carriagewaywhich it covers must be clearly delineated with white lines and related supportsigning. Detailed guidance is provided in TSM 10 paragraphs 7.18 - 7.19. Paragraph 7.19also deals with the use of black and yellow hazard markings to emphasise the part ofthe structure at risk. These too should be reflectorised. Guidance on the use of roadmarkings to guide high vehicles through arches can be found in TSM 11 paras 22.5 - 22.10.3.19 It is possible to have a side chord(s) alone markedwhere the centre chord affords a headroom of atleast 16’-6” (5.03m). In this case there will be noadvance restriction signing for the site butcarriageway white lining and related signing shouldbe applied as above.3.20 For a bridge less than 3.0m wide the chord willcover the span between kerbs if they exist andthe full span where they don’t.Side chord only signed. Main arch >=16’-6”therefore no restriction on use of road3.21 Signs, including those on the bridge elevations, must be illuminated when they are ona road which has a system of street lighting, as defined in the Traffic Signs Regulationsand General Directions (TSRGD) 12 .3.22 See Appendix B for details of other options for supplementary signing.3.23 The shape, size, background colour, size of lettering, etc, on a sign, is specified in theTSRGD 12 . Further guidance can be found in Chapter 4 13 and 7 14 of TSM. Thisincludes advice on the sizes of sign appropriate for different traffic speeds (Chapter 4paragraphs 1.13 – 1.18, 7.14, 7.17, 7.18 and appendix A). Where alternatives areallowed then the sensitivity of the site to bridge strikes, the frequency of strike,the environment and any local signing policy must also be given due consideration andrelevant priority in determining the eventual choice.10 & 13Traffic Signs Manual Chapter 4 ‘Warning Signs’ (2004) London: TSO for DfT et al.11Traffic Signs Manual Chapter 5 ‘Road Markings’ (2003) London: TSO for DfT et al.12Traffic Signs Regulations and General Directions, (2002) London: TSO14Traffic Signs Manual Chapter 7 ‘The Design of Traffic Signs’ (2003) London: TSO for DfT et al.9

Prevention of Strikes on Bridges over HighwaysA Protocol for Highway Managers and Bridge Owners3.24 The siting of signs needs particular care. Detailed advice on this is given in TSM 15paragraphs 1.19 – 1.22, and appendix A therein specifies minimum clear visibilitydistances. Signs must be located in a place and at a height where they are visible to allrelevant traffic on every approach. This will determine the number of signs needed atany junction. Anticipating the growth of vegetation which might restrict visibility isparticularly important.Signing of diversion routes3.25 Diversion routes around restricted bridges are notroutinely signed. It is not mandatory to do so, but ifa structure is frequently struck, serious considerationshould be given to the provision of signing to divertover-height vehicles to an alternative route. Furtherguidance is provided in TSM 16 paragraph 7.10.3.26 There will, however, always be a presumption against an unnecessary proliferation ofsigns. This is both for environmental reasons in rural areas and to avoid too muchconflicting and potentially distracting information in urban areas. This can beespecially marked where there are two or more low bridges in close proximity toone another. Blanket installations of diversion routes would also increasesignificantly the installation and maintenance costs of the signs.3.27 The responsibility for assessing the adequacy of a diversion route rests with thehighway authority. In determining this, it is important that vehicles are not divertedunder a lower bridge or through another inappropriate restriction. Similarly, diversionroutes for road works closures should not send traffic under bridges lower thanthose on the route closed.3.28 Where a signed diversion exists or is to be implemented,advanced warning should be given as early as reasonablypracticable to minimise abortive travel. The same advice appliesfor locating advance signs which advise of the restriction butwhere the diversion route is not signed. Symbols may be usedto simplify the signing around the diversion route.3.29 Route Planning - A national controlled database of signed bridge headrooms is beingpromoted as part of the Department for Transport’s Electronic Service Delivery ofAbnormal Loads (Notifications), (ESDAL), Project. When available, hauliers andcommercial interests producing atlases and satellite navigation systems will have accessto real time data on which to base their route planning and direction aids. This clearlyoffers the safest practice but if it is to work effectively, every highway authority mustprovide and maintain details of the signed maximum safe vehicle height at its lowbridges and make every effort to also feed in any temporary restrictions.15 & 16Traffic Signs Manual Chapter 4 ‘Warning Signs’ (2004) London: TSO for DfT et al10

Prevention of Strikes on Bridges over HighwaysA Protocol for Highway Managers and Bridge Owners4.0 Maintenance of signs4.1 It is important that highway authorities identify clearaccountability for providing, inspecting and maintainingall signs for low headrooms, both lit and unlit andat all locations. It is equally important that thoseinvolved with this work understand the importanceof the need for correct signing, the actual potentialdangers which arise as a result of bridge strikesand the implications for a highway authority if theHazard markings wrong,could be a roundel, sign displacedstrike can in any way be attributed to negligence or poor practice on their behalf. Itis important that the hazard markings are considered an integral part of the signingsystem and are similarly maintained.4.2 Traffic signs should be visible at all times, winter, summer, wet and dry, day and night.This is especially the case where the implications if the signs are not visible, couldbe catastrophic. Signs to advise of safe vehicle height to protect low bridges must fallinto this category. Guidance on sign cleaning and maintenance is given in TSM 17paragraphs 1.38 – 1.40 and in TD 25/01 18 (see paras 5.1.1 - 5.1.3).4.3 A regular routine of inspection of signs and relatedwhite lines at these sites must therefore be carriedout to ensure that faults are identified and reported.A maintenance regime to cover routine and, ifnecessary, reactive maintenance must also beoperated to keep signing systems in good conditionand ensure that any faults are rectified promptly.This is especially important in respect of the signs at and on a bridge which mustalways be clearly visible to drivers.Vegetation starting to obscure hazard markings4.4 Inspectors must be fully aware of the impact of changingconditions both seasonal and during the hours ofdarkness. Issues of cleanliness and loss of reflectivity ofsigns including black and yellow hazard markings, fadingwhite lines and broken lighting all need to be reported.Also, the inspector needs to be aware of all signs relatingto each restriction to ensure they are all covered and tobe awake to missing signs. They should also consider theneed for additional signs to cover sites where visibility fromdifferent approaches is difficult. Particular attention mustbe given to the location of signs and keeping surroundingvegetation in check to ensure that they can be seen at alltimes.Vegetation and shadowsobscuring signsSign not legible17Traffic Signs Manual Chapter 4 ‘Warning Signs’ (2004) London: TSO for DfT et al.18TD 25/01 ‘Inspection and Maintenance of Traffic Signs on Motorway and All Purpose Trunk Roads’ in DMRB Volume 8 ‘Traffic Signsand Lighting’, Section 2, Part 2, (February 2001) London: TSO for Highways Agency 11

Prevention of Strikes on Bridges over HighwaysA Protocol for Highway Managers and Bridge Owners4.5 Ideally a special proforma for reporting these specific defects should be developed. Asample is given in Appendix C. Responsibilities for actioning remedial works should beclearly defined.4.6 Signs damaged following a bridge strike or other road accident must be replacedimmediately. In this regard, it is important the highway authority is formally notifiedby bridge owners of any strikes on their bridges.4.7 It is accepted that highway authorities will have differing priorities/strategies in theirTransport Asset Management Plan for inspecting and maintaining signs but, withinthat relevant strategy, signs for restricted headrooms must be included with those ofthe highest category of priority.4.8 There may be access difficulties for maintaining signs placed on bridges resultingfrom train related hazards and/or the need for road closures. Neither of theseshould prevent a sign from being attached to a bridge if that is what is needed. Inthese circumstances, the highway authority and Network Rail should agree who isbest placed to carry out maintenance and the protocol for so doing.5.0 Other protection techniques5.1 There are a number of other tools in the kit for supplementing signing where problemsof bridge strikes persist. They, together with comments, are described in Appendix B.5.2 It is important for highway authorities to engage with bridge owners such as NetworkRail when considering further action as they will have a wider appreciation of whatsolutions have been tried nationwide and their relative success.6.0 Distractions from advertising6.1 Advertisements distract drivers’ attention. It is therefore recommended that theyshould not be allowed on or adjacent to bridges spanning over the highway. Thisincludes bridges owned by Network Rail and others.12

Prevention of Strikes on Bridges over HighwaysA Protocol for Highway Managers and Bridge Owners6.2 It is further recommended that where such advertising has been licensed in the pastit should not be renewed.6.3 The erection of local event banners on or in the vicinity of bridges over the highwayshould similarly be banned, notwithstanding historical precedents. There are additionalconcerns here about accidents happening while these are being put in place andremoved or from vandals loosening them while in place.6.4 Much more careful consideration should also begiven by planning authorities when processingapplications for advertising on private land alongsidethe highway, especially in the vicinity of restrictedheight or lightweight bridges. Such approval shouldnot be granted where drivers may be distracted,miss important road signs and so increase thelikelihood of a bridge strike.Distracting advertising. Also, signing could beimproved, chevrons wrong, extends overfootway. Limit sign too high, could be roundel7.0 Lighting in the vicinity of railways and underbridges7.1 Highway lighting should not interfere with a train driver’s vision of signals.7.2 Any highway lighting scheme in the vicinity of a railway should be submitted toNetwork Rail for comment and approval prior to implementation.7.3 Consideration must be given to the need for lighting under a wide (ie along thecarriageway) overbridge and particularly to highlight the lowest section of the soffitif it lies within the bridge.8.0 Temporary works and working practices8.1 When erecting temporary access or working platforms at any bridge spanning overa highway, care must be taken not to allow any projections beneath the soffit of theexisting bridge except(a) where the road or lane is closed to traffic; or(b) where the minimum clearance above the carriageway under the temporaryworks can be maintained at more than 17’-9” (5.41m), the minimum maintainedrequirement for headroom under lightweight structures.13

Prevention of Strikes on Bridges over HighwaysA Protocol for Highway Managers and Bridge Owners8.2 No temporary works, traffic management or working methods on the road belowshould force traffic under a section of bridge with less headroom than the areabeing obstructed, whether it is a signed bridge or not, without careful assessment ofany potential adverse effects. Also, they should not force vehicles to mount kerbedfootways which could further increase likelihood of impact.8.3 This applies to any works and highway authorities must be particularly vigilant inrespect of works by utilities and other outside parties. Bridge owners also mustensure, during their own works, that they do not block the view of signs on bridges,or they provide replacement signs if this is unavoidable.8.4 A point of particular importance relates to works which reverse the direction of flowalong a road or divert traffic onto contraflow working on another carriageway. It isimperative that proper signing is in place to reflect the directional change.8.5 Highway authorities must ensure that those involved in the process of approvingwork on the highway are aware of these issues.9.0 Joint working with Network Rail, LondonUnderground Ltd and other bridge owners9.1 The issue of protecting the travelling public at rail over road bridges is a jointresponsibility between the highway authority and Network Rail, LondonUnderground Ltd (LUL) or other bridge owners, as appropriate. In this, both partiesshould work together to reduce the risk of bridge strikes.9.2 It is recommended that regular meetings are held between the highway authority andthe appropriate body to discuss relevant issues and, when appropriate, other interestedstakeholders such as emergency services, planning authorities, transport organisationsor even individual haulage companies should be invited to attend.9.3 The lack of primary legislation in respect of a duty to sign headrooms and the seekingof approval to move high loads, coupled with the popular misunderstanding amongdrivers of what the 16’-6” threshold means, creates particular difficulties. However, itis accepted that, as part of their general duty of care under the Highways Act, highwayauthorities will sign all bridges over highways with less than 16’-6” (5.03m) minimumactual headroom at any point over the carriageway, at least to the minimum required,and will also maintain the signing.9.4 Where a height survey shows a change in signed height to be necessary, the highwayauthority should inform the bridge owner of the proposal before implementation.14

Prevention of Strikes on Bridges over HighwaysA Protocol for Highway Managers and Bridge Owners9.5 Where Network Rail, LUL or other bridge owners believe that road traffic signsconforming to current standards are still not effective in preventing bridge strikesoccurring, it is reasonable for them to promote enhancements of the signing throughthe highway authority. Funding for such enhancements may be in a joint venturewith the highway authority, or be fully funded by the bridge owner, especially wherewarranted by a business case.9.6 In all situations, including where external funding is available, implementation of thesigning enhancement scheme must still be through the highway authority andongoing inspection and maintenance will be their responsibility even if there is anagreement about work or cost sharing.10.0 Other important considerations10.1 Highway authorities should ideally include the issue of bridge strikes, the potentialconsequences and need for protective measures in their Transport AssetManagement Plans.10.2 Planning authorities must consider the implications for low bridges in any developmentproposals both during construction and eventual operation. This should ensure thatthe necessary steps to increase headroom, enhance signing and/or impose trafficmovement restrictions are included as a condition in any eventual approvals given.10.3 A highway authority must clearly define within its staffing structure who is responsiblefor the inspection and maintenance of headroom signs.10.4 A highway authority should also define where responsibility for receiving andreacting to information about sites sensitive to bridges strikes lies and who shouldattend liaison meetings referred to in 9.2.10.5 Highway authorities must maintain a register of all bridges, their owners and theavailable headroom and maximum safe vehicle height on the carriageway under thebridge.10.6 When reviewing any site which has particular problems or in developing inputs toTransport Asset Management Plans, reference could usefully be made to the TransportResearch Laboratory investigation referenced in 12.1d overleaf. In particular, thebridge audit check sheet (see Appendix E) will be a useful aid on these occasions, aswell as in the meetings in 9.2 and also as an aide-memoire for inspectors whencompleting the report form.15

Prevention of Strikes on Bridges over HighwaysA Protocol for Highway Managers and Bridge Owners11.0 Action to take when informed of a bridge strike11.1 At a Network Rail bridge11.1.1 Network Rail is carrying out a programme to erectidentification plates at all bridges spanning or carryingtheir railway. An example is shown.11.1.2 When Network Rail are advised of a strike on one oftheir bridges, they should immediately inform therelevant highway authority.11.1.3 Should a highway manager receive advice of a bridge strike at a Network Rail bridgefrom someone other than Network Rail, the informant should be asked if Network Railhas been advised. If Network Rail has not been notified they should be contactedimmediately using the telephone number on the identification plate, if available, or the24 hour number held by the authority. In all cases the information on the identificationplate should be ascertained and the date and time of the incident recorded.11.1.4 If the incident is current, the Police should then be contacted using the 999 system.11.1.5 Following receipt of a report of the bridge strike:(a) Network Rail will examine the structure of the bridge.(b) The highway authority too should inspect the site and make urgent arrangementsto repair any damage to road signs, markings and lighting, liaising, as necessary, withNetwork Rail for access to repair damaged signs attached to the bridge. This shouldinclude checking the minimum headroom (see 3.5, 3.6 and 3.7) so as to confirm oramend any signed maximum safe vehicle height.(c) In the event that there is any doubt as to the condition of the bridge, then the roadmust be closed pending the outcome of the structural inspection and thecompletion of any remedial works considered necessary for public safety.11.1.6 Following a bridge strike at a bridge with a history of strikes, a meeting as described in9.2 should be set up to determine if any improvements can be made to the signing onthe approaches and at the bridge or other appropriate action taken.11.2 At a highway authority bridge11.2.1 In the event of a strike on a road over road bridge or footbridge, the highwayauthority Bridge Manager must be contacted immediately who will arrange for the siteto be inspected and where necessary, a structural inspection must follow. In the eventthat there is any doubt as to the condition of the bridge, traffic on and under it mustbe stopped pending the outcome of the structural inspection and the completion ofany remedial works considered necessary for public safety.16

Prevention of Strikes on Bridges over HighwaysA Protocol for Highway Managers and Bridge Owners11.2.2 It is unlikely that any of these will be low bridges but in the event that they arethen the further actions in 11.1.5 (b) must also be carried out.11.3 At a bridge owned by others11.3.1 In the event of a strike on a bridge owned by others which spans the highway, the bridgeowner and the highway authority Bridge Manager must be contacted immediately.Whether or not the bridge owner responds quickly, the Bridge Manager or equivalentwill arrange for the site to be inspected immediately and, where necessary, ask the ownerto undertake a structural inspection. In the event that there is any doubt as to the conditionof the bridge, traffic on and under it must be stopped pending the outcome of thestructural inspection and the completion of any remedial works considered necessaryfor public safety.11.3.2 In the event that the bridge is a low signed structure the further actions in 11.1.5(b)must also be carried out.12.0 Other useful documents12.1 There have been a number of useful documents produced recently which are worthreading to assist in understanding the issues around bridge strikes and the effortsbeing made to prevent them happening:a) Traffic Advisory Leaflet. Signing Measures to Reduce Over Height Vehicles Striking RoadBridges. (Published by the Department for Transport and TRL Ltd.). This gives advice onthe do’s and don’ts of signing for restricted headrooms. (In preparation).b) Prevention of Bridge Strikes: A good practice guide for transport managers. (Publishedby Network Rail. Prepared in collaboration with the freight industry). A pocket sizedocument explaining the law, the consequences of bridge strikes, actions totake to avoid them and what to do if a strike occurs.c) Prevention of Bridge Strikes: A good practice guide for professional drivers. (Published byNetwork Rail. Prepared in collaboration with the freight industry). A pocket sizedocument explaining the law, the consequences of bridge strikes, actions to take toavoid them and what to do if a strike occurs.d) Measures to Reduce the Frequency of Over-height vehicles Striking Bridges. (Aninvestigation undertaken and report prepared by TRL Ltd for the Department for Transport’sBridge Strike Prevention Group). This project involved interviewing drivers, highwayauthorities and other stakeholders involved in the movement of HGVs aroundthe highway network. Incident records were reviewed to see if there were anytrends and recommendations for actions are made to assist in the campaign toreduce the frequency of strikes. Recommendations relating to highway authoritiesare mostly covered in this protocol.17

Prevention of Strikes on Bridges over HighwaysA Protocol for Highway Managers and Bridge Ownerse) Prevention of Bridge Strikes – A Good Practice Guide for Passenger TransportOperational Staff. (Ref no. NR/GPG/CIV/005). (Published by Network Rail. Prepared incollaboration with the passenger transport industry). A pocket size documentexplaining the law, the consequences of bridge strikes, actions to take to avoidthem and what to do if a strike occurs.f) Prevention of Bridge Strikes – A Good Practice Guide for Professional Drivers of PassengerVehicles. (Ref no. NR/GPG/CIV/006). (Published by Network Rail. Prepared incollaboration with the passenger transport industry). A pocket size documentexplaining the law, the consequences of bridge strikes, actions to take to avoidthem and what to do if a strike occurs.18

Prevention of Strikes on Bridges over HighwaysA Protocol for Highway Managers and Bridge OwnersBibliographyDesign Manual for Roads and Bridges (DMRB) Volume 2 ‘Highway Structures: Design(Substructures and Special Structures) Materials’ London: TSO for Highways AgencyDesign Manual for Roads and Bridges (DMRB) Volume 6 ‘Road Geometry’ London: TSO forHighways AgencyDesign Manual for Roads and Bridge (DMRB) Volume 8 ‘Traffic Signs and Lighting’ London:TSO for Highways AgencyTraffic Signs Manual Chapter 4 ‘Warning Signs’, (11 June 2004), London: TSO for DfT, the ScottishExecutive, the Welsh Assembly Government and the Department for Regional Development NITraffic Signs Manual Chapter 5 ‘Road Markings’, (7 November 2003), London: TSO for DfT,the Scottish Executive, the Welsh Assembly Government and the Department for RegionalDevelopment NITraffic Signs Manual Chapter 7 ‘The Design of Traffic Signs’, (10 December 2003) London:TSO for DfT, the Scottish Executive, the Welsh Assembly Government and the Departmentfor Regional Development NITraffic Signs Regulations and General Directions 2002 (SI2002 no.3113) London: TSOBD 65/97 ‘Design Criteria for Collision Protection Beams’, in DMRB Volume 2 ‘Highway Structures:Design (Substructures and Special Structures) Materials’, Section 2, Part 5, (February 1997),London: TSO for Highways AgencyTD 27/05 ‘Cross Sections and Headrooms’ in DMRB Volume 6 ‘Road Geometry’, Section 1, Part 2,(February 2005), London: TSO for Highways AgencyTD 25/01 ‘Inspection and Maintenance of Traffic Signs on Motorway and All-Purpose Trunk Roads’in DMRB Volume 8 ‘Traffic Signs and Lighting’ Section 2, Part 2 (February 2001), London: TSOfor Highways AgencyTraffic Advisory Leaflet. Signing Measures to Reduce Over Height Vehicles Striking Road Bridges.(Published by the DfT and TRL Ltd).Prevention of Bridge Strikes: A Good Practice Guide for Transport Managers. (Published byNetwork Rail, prepared in collaboration with all parts of the freight industry)Prevention of Bridge Strikes: A Good Practice Guide for Professional Drivers. (Published byNetwork Rail, prepared in collaboration with all parts of the freight industry)19

Prevention of Strikes on Bridges over HighwaysA Protocol for Highway Managers and Bridge OwnersPrevention of Bridge Strikes: A Good Practice Guide for Passenger Transport OperationalStaff. (Published by Network Rail, prepared in collaboration with all parts of the passengertransport industry)Prevention of Bridge Strikes: A Good Practice Guide for Professional Drivers of PassengerVehicles. (Published by Network Rail, prepared in collaboration with all parts of the passengertransport industry)Measures to Reduce the Frequency of Over-height Vehicles Striking Bridges. (An investigationundertaken and report prepared by TRL Ltd. for the DfT’s Bridge Strike Prevention Group).20

Prevention of Strikes on Bridges over HighwaysA Protocol for Highway Managers and Bridge OwnersAPPENDIX ASurfacing activities under bridges over highwaysA.1 There will always be a presumption against raising surface levels under any bridge. However,there may be situations where overlays can be considered. Guidance is given belowfor bridges with different clearances but any request must be referred to andcleared by both the highway authority’s Bridge Manager and Network Rail or otherbridge owner.A.2 Network Rail in some cases has a legal obligation to provide a specific minimumheadroom. This must not be compromised except by formal amendment to theoriginal agreement, approved by all parties.A.3 Unsigned bridges with 16’-6” (5.03m) or more headroomA.3.1.Bridge deck is designed or has been assessed as able to resist vehicle impact forces,current at the time of the surfacing works, as advised/agreed by the bridge owner:(a) if existing headroom is 16’-6” (5.03m) or more allow reduction to 16’-9” if sought.(b) if existing headroom is between 16’-9” (5.1m) and 16’-6” (5.03m) then no reductionis allowed and efforts should be made to increase it to 16’-9”.A.3.2A.3.3Lightweight structures not capable of resisting current impact forces as advised/agreed by the bridge owner:(a) if existing headroom is greater than 17’-9” (5.41m) allow reduction to 17’-9” if sought.(b) if existing headroom is between 17’-9” (5.41m) and 16’-6” (5.03m) then no reductionis allowed and efforts should be made to increase it to 17’-9” or as high as possibleand at least to 16’-9” if lower than this.Relevance of different clearances:A.3.3.1 Chapter 6 of TD 27/05 19 specifies headrooms, including additional provision forsag curve compensation (S), for new construction and maintenance as follows:• 16'-6” (5.03m) + S is the standard minimum maintained headroom below which allbridges should be signed.• 17'-5” (5.30m) + S is the standard design headroom over the accessible highwayfor new bridges designed to resist current impact forces and for those built sincethe earlier version of TD 27 came into force in 1996.• 18'-9” (5.7m) + S is the standard design headroom over the accessible highwayfor new lightweight structures, ie, those not designed to resist impact forces, andfor those built since the earlier version of TD 27 came into force in 1996.• 17'-9'’ (5.41m) + S is the equivalent minimum maintained headroom for newlightweight structures and those built since the earlier version of TD 27 cameinto force in 1996.19TD 27/05 ‘Cross Sections and Headrooms’ in DMRB Volume 6 ‘Road Geometry’, Section 1, Part 2, (February 2005) London:TSO for Highways Agency21

Prevention of Strikes on Bridges over HighwaysA Protocol for Highway Managers and Bridge Owners• Design headroom is provided for structures at construction and allows forsubsequent limited surfacing overlays for maintaining the highway beneath.• Maintained headroom is that minimum which must not be reduced at any timeand which will consequently determine, along with other local issues, thepossibility of overlaying.A.3.3.2 The CSS suggests that highway authorities should over time aim to make 16'-9”(5.10m) the minimum maintained headroom for all bridges prior to signing due toconfusion in drivers’ minds that 16’-6” (5.03m) represents the safe vehicle height forunsigned bridges rather than the actual minimum headroom.A.4 Signed bridges with less than 16’-6” (5.03m) headroomA.4.1There will be a presumption against any reduction in the existing headroom providedunder low signed bridges. The highway authority and Network Rail/bridge owner jointlyshould determine every case. See also paragraph A2.A.4.2A.4.3A.4.4When undertaking maintenance work, consideration must be given to improving thesituation and especially to seeking ways of providing the current minimum maintainedheadroom standards of 16’-6” (5.03m) (or 16'-9'’ as suggested in A.3.3.2 above) and17’-9” (5.41m) as appropriate. Special thought must be given to the implication forthose sites where the ‘improvement’ in safe vehicle height would enable the removalof the need to provide ‘protection’ by signing where the bridge is currently low.Consideration should also be given at that time to extending the headroomrequirement to the whole of the accessible highway.Although there will, in theory, be scope to allow a raising of levels where the signedclearance gives a safety margin between 3” and 6”, it is not recommended that sucha concession is made because practice has shown that ‘regular’ drivers’ of highervehicles go through because they know they have managed it before. Such changescould therefore increase the risk of bridge strikes.Care should be taken when considering changes in signed safe vehicle heights as somesites seem to be more susceptible to impact. There is probably a relationship betweenstandard vehicle heights and range of headrooms and so the traffic use could influencethe decision. More research is needed however before definitive guidance on thiscan be given.A.5 High Load Routes - (20’-0”)A.5.1 No reduction under 20’-3” (6.18m) will be allowed.22

Prevention of Strikes on Bridges over HighwaysA Protocol for Highway Managers and Bridge OwnersAPPENDIX BAdditional options for protecting against bridge strikesB.1 In addition to road signs, there are a number of other tools in the kit for protectingbridges from or preventing bridge strikes. They, together with comments, are givenbelow.B2B.2.1False soffitsFalse soffits are used on bridges which have asignificant difference in clearance between portals,eg, as on an up-grade. They are to prevent thedriver of an overheight vehicle approaching theside with greater clearance thinking he can getthrough and then being wedged under ordislodging the lower exit side. They are generallyformed by hanging rubber flaps on the side withthe greater clearance to visually match the lesser envelope. Guidance on theprovision of false soffits is given in TSM 20 paragraphs 7.20 – 7.22.B.3 Collision protection beams (CPBs)B.3.1Collision protection beams are installations designed to absorb the shock of animpacting vehicle and so protect the structure of a bridge. As such they aregenerally built into the existing bridge abutments because the governing designstandard, BD65/97 21 , does not permit free standing supports over the highway asthey would create an additional and avoidable hazard to traffic.B.3.2Whilst CPBs may be installed under the terms covering the original bridgeconstruction, approval from the highway authority is also required to protect theinterests of the authority and users of the public highway. This would cover issuesof headroom, signing and access to do and maintain the works and would alsoinclude a role of joint signatory in the formal structural technical approval process.A formal licence may be required if a substantive change to the highway is sought orwhere the original terms of agreement are exceeded.B.3.3If the bridge is a listed building or in the curtilageof one, consent from the local planning authoritywill also be needed. If the site is in a conservationarea, contact should again be made with the localplanning authority to see if they have anypreferences which might be accommodated in thescheme.Signs should be in advance of beam20Traffic Signs Manual Chapter 4 ‘Warning Signs’ (2004) London: TSO for DfT et al.21BD 65/97 ‘Design Criteria for Collision Protection Beams’ in DMRB Volume 2 ‘Highway Structures: Design (Substructures andSpecial Structures) Materials’, Section 2, Part 5, (February 1997) London: TSO for Highways Agency 23

Prevention of Strikes on Bridges over HighwaysA Protocol for Highway Managers and Bridge OwnersB.3.4.Collision protection beams are likely to befractionally lower than the actual bridge soffit andso the headroom clearance must be recheckedand any necessary adjustments made to the signingbefore traffic is allowed access under the bridge.The promoter of the protection scheme shouldallow for and meet the cost of any relatedre-signing.B.4 Infra red beams with variable message signs (VMS)B.4.1Infra red beams are placed in advance of the bridge and are set at the restricted signedheight so that they activate the variable message sign if the beam is broken by a vehicle.A message on the screen of the VMS warns the driver of the offending vehicle to stopand divert.B.4.2B.4.3B.4.4B.4.5Sufficient distance is necessary for beam and sign to be located in advance of thebridge both for the sign to respond and for the driver to read and react to its message.Infra red beams can suffer from malfunction due to beam misalignment and so it isessential to have a clear default message indicating when the sign is not working.Each installation should have a robust maintenance contract which includes anemergency response requirement to deal with a malfunction.These installations can be further supplemented with cameras to photograph theoffending vehicles.B.5 Supplementary signing/white linesB.5.1Additional signs placed outside factory/warehouse entrances lyingbetween the last junction and the bridge can offer a timelyreminder to drivers leaving the site, especially where the exit isbetween the bridge and the last advance warning sign.B.5.2B.5.3TSM 22 gives details on appropriate sign sizes but there may besituations where larger signs might be considered appropriateto afford better visibility. Approval should be sought from theregional government office if this is considered desirable.Arrow should be spaced betterUse ‘SLOW’ painted on the road to warn drivers of the restriction and thus increaseability to stop/reduce force of impact. This must only be in conjunction withappropriate signing (TSM chapter 5). Alternatively, introduce a lower speed limit ifappropriate.22Traffic Signs Manual Chapter 4 ‘Warning Signs’ (2004) London: TSO for DfT et al.24

Prevention of Strikes on Bridges over HighwaysA Protocol for Highway Managers and Bridge OwnersB.5.4B.5.5Use a supplementary weight or width restriction to reduce the size of vehicles usingthe route.Consider the potential benefits of reflectorisation of painted striped hazardmarkings or the use of fluorescent sheeting. See TSM 23 paragraphs 7.2, 7.5, 7.15, 7.19and 7.22 for guidance on flourescent hazard warnings and TSM 23 paragraph 1.32 andTSM 24 paragraphs 14.19 - 14.21 for advice on flourescent backing boards.B.6 Other possible considerationsB.6.1 Traffic calming techniques in advance of the bridge.B.6.2B.6.3B.6.4B.6.5B7B.7.1Use of trief kerb to delineate the ‘central’ lane and so force vehicles into the saferzone under an arch. It may be necessary to consider a vehicle tyre mounting thelower lip of the trief kerb in determining the location of the kerb line and/or heightrating of the bridge. They can also be used to protect against impact on columns.Vertical concrete barrier might be another alternative.Lower the carriageway to increase headroom. Whilst this is always likely to be the morepractical option than raising the railway, it is also a solution with problems creating, as itdoes, a sag curve. This increases the depth required to achieve the headroom andcauses drainage problems and potential interference with services.Install traffic lights to restrict traffic to alternate singleline working. This is particularly effective at an archbridge to ensure vehicles go under the centre chordand at narrow bridges where there is insufficientwidth for vehicles to pass. Generally, they also havethe effect of slowing traffic although vehicles dosometimes race to beat the lights. Alternativescould be priority working or a full give wayinstallation (to oncoming traffic).The ultimate deterrents are a lorry ban or fullclosure to vehicular traffic.Skew bridgesBridge strikes at skew bridges can cause the vehicleto overturn. In such cases there is a significant risk that, in addition to the risk to thedriver of the offending vehicle, an innocent driver of a vehicle passing in the oppositedirection or pedestrians will be fatally or seriously injured.23Traffic Signs Manual Chapter 4 ‘Warning Signs’ (2004) London: TSO for DfT et al.24Traffic Signs Manual Chapter 7 ‘The Design of Traffic Signs’ (2003) London: TSO for DfT et al.25

Prevention of Strikes on Bridges over HighwaysA Protocol for Highway Managers and Bridge OwnersB.7.2A vehicle may overturn at a skew bridge with or without an impact protectionbeam. Where vehicles have overturned, the speed of the vehicle appears to havebeen the main contributory factor and thus mitigation that contributes to areduction in vehicle speed at the bridge will reduce the risk of a vehicle overturning.APPENDIX CSample sign inspection report formC.1 An inspection report form for the signing associated with a headroom restriction shouldideally comprise:(a) A reminder of what to look for.(b) The report form.(c) A map showing the location of the bridge and signs to be inspected.C.2 The survey and plotting to produce the map will probably be a development need butone in which authorities are encouraged to invest.26

Prevention of Strikes on Bridges over HighwaysA Protocol for Highway Managers and Bridge OwnersHighway Structures OfficeBridge Headroom/Weight Limit Signs InspectionBr No:Br Name:Inspector: District/Area: Date:Headroom/Weight* Limit Signs (*delete as applicable)Limit• This report must cover all signs on the bridge, at the bridge and in advance of the bridge.• Additionally it should cover the further direction flag signs.• Specific note must be made of:1. Surface Condition – Cleanliness. (G/F/P)2. Surface Condition – Reflectiveness (night time check). (G/F/P)3. Any overhanging vegetation. (Y/N)4. Visibility to on-coming traffic especially from each (G/F/P)approach at a junction.5. Illumination in place if needed (night time check). (Y/N)6. Illumination working. (Y/N)7. Need for sign to be moved. (Y/N)8. Need for additional sign(s). (Y/N)9. Condition of road markings. (G/F/P)G - GOODF - FAIRP - POORY - YESN - NO27

Prevention of Strikes on Bridges over HighwaysA Protocol for Highway Managers and Bridge OwnersHighway Structures OfficeBridge Headroom/Weight Limit Signs InspectionBr No:Br Name:Dist: Inspector: Area: Date:Headroom/Weight* Limit Signs (*delete as applicable)LimitSign Item Cond CommentsLocation (G/F/P)(see map) or (Y/N)1 123456782 123456783 1234567828

Prevention of Strikes on Bridges over HighwaysA Protocol for Highway Managers and Bridge OwnersSign Item Cond CommentsLocation (G/F/P)(see map) or (Y/N)4 123456785 123456786 12345678At Bridge 9NOTES29

Prevention of Strikes on Bridges over HighwaysA Protocol for Highway Managers and Bridge OwnersAPPENDIX DExamples of sites where signing could be improvedPoor or no hazard marking.Sign could be a roundel.Metric dimensions on signs don’t match. Signsnot illuminated. 4m should be 4.0m. Advancesign should not have black edging.Hazard marking is wrong andextends too far.Hazard marking does not covercarriageway.Hazard marking wrongly configured.Signs can be changed to roundels.Hazard markings missing and extends beyondchords. Side chords not signed in metric. Verticalhazard marking on abutment because no vergeunder bridge.30

Prevention of Strikes on Bridges over HighwaysA Protocol for Highway Managers and Bridge OwnersNo hazard marking. Sign could be roundel.Hazard marking not central.Sign too high and could be roundel.Poor location for camera sign.Long chord exceeds 10’ (3m). This will reducesignificantly signed height but is not wrong.Hazard markings extend over footway.Hazard marking painted, not reflectorisedand wrongly configuredWhen signing low bridgesTake heedIt’s sometimes advice you needWhen signing low bridgesTake careIt needs to be right - beware31

Prevention of Strikes on Bridges over HighwaysA Protocol for Highway Managers and Bridge OwnersAPPENDIX ETRL - Bridge Audit Check SheetBridge LocationBridge Audit Check SheetSigned height [Current signed height] [Height after re-measuring](feet/inches)Date of auditAdvance signingSigning:• Is it there?• Is it adequate?• Is it in the right place?Comments:Is the bridge signed on its Yes / No Comments:approach from both directions?Is advance signing used at Yes / No Comments:junction points on theapproach to the bridge?What signs have been used?List:Consider the following:• Warning or mandatory signs -non-arch bridges (diagrams530, 629.2, 629.2A and 818.3);• Warning signs - arch bridges(diagrams 530, 531.1 - witharch bridge symbol and 531.2)Do the signs conform to the Yes / No Comments:current regulations (TSRGD 2002)?Are the signs in good condition?Comments:Consider the following:• Cleanliness• Damage• Graffiti• ObscuredIs there unacceptable sign clutter? Yes / No Comments:32

Prevention of Strikes on Bridges over HighwaysA Protocol for Highway Managers and Bridge OwnersIs it appropriate to consider Yes / No Comments:adopting measures to make the signsmore conspicuous (eg rectangularyellow backing boards)?Signing at the bridgeAre warning or mandatory signs Yes / No Comments:located on both sides of the bridge?Does the signed height at the Yes / No Comments:bridge agree with that shown inthe AA Truckers Atlas of Britain(if applicable)?What signs have been used?List:Consider the following:• Warning or mandatory signs -non-arch bridges (diagrams530, 629.2 and 629.2A);• Warning signs - arch bridges(diagrams 530 and 531.1);• Chevrons - non arch bridges(diagram 530.2)• Chord markings - arch bridges(diagram 532.2)• Road markings - non arch bridges• Lane and road markings -arch bridges (diagrams 1010,1014 and 1024.1)Do the signs conform to the Yes / No Comments:current regulations (TSRGD 2002)?Are the signs in good condition?Comments:Consider the following:• Cleanliness• Damage• Graffiti• Obscured• Condition of H bars (archbridges only)Is there unacceptable sign clutter? Yes / No Comments:33

Prevention of Strikes on Bridges over HighwaysA Protocol for Highway Managers and Bridge OwnersIs it appropriate to consider Yes / No Comments:adopting meaures to make the signsmore conspicuous (eg rectangularyellow backing boards)?Is it appropriate to consider Yes / No Comments:using markings on the bridge?eg ‘LOW BRIDGE’Provision of Alternative RouteIs there a signed alternative route? Yes / NoComments:Is the alternative route suitable Yes / No Comments:for high vehicles?What signs have been used?List:Consider the following:• Primary route direction signs(diagrams 2002, 2003 and 2027);• Non-primary route direction signs(diagrams 2107, 2108 and 2132);• Informatory signs (diagrams 818.3and 818.4)Do the signs conform to the Yes / No Comments:current regulations (TSRGD 2002)?Are the signs in good condition?Comment:Consider the following:• Cleanliness• Damage• Graffiti• ObscuredIs there unacceptable sign clutter? Yes / No Comments:Use of Specific MeasuresIs it appropriate to consider the Yes / No Comments:use of Variable Message signs (VMS)?Consider the following:• Use on approach as warning ordiversion signing• Location• Functioning correctly• Free from foliage34

Prevention of Strikes on Bridges over HighwaysA Protocol for Highway Managers and Bridge OwnersIs it appropriate to consider the Yes / No Comments:use of automatic detectionsystems (with cameras)?Is it appropriate to consider the Yes / No Comments:use of impact protection beamson bridge?Is it appropriate to consider the Yes / No Comments:use of other forms of detectionsystems (eg chains)?General ConsiderationsNumber of reported strikes inprevious 12 monthsDate of last bridge strikeAmount of HGV traffic passingunder bridgeAny weight restrictions on theroute under the bridgeAdjacent land usePresence and location of anyother low bridges nearbyScope for a high sided vehicle tomanoeuvre, ie turn around inthe vicinity of the bridgeGeneral bridge condition inparticular structural weaknessesAre there distractingadvertisements on theapproaches to the bridge?Is the lighting adequate for thesigns and at the bridge?35

Prevention of Strikes on Bridges over HighwaysA Protocol for Highway Managers and Bridge OwnersRegistration, feedback and contacts1 Registration1.1 To facilitate maximum circulation of any updating of the Protocol and so ensure, asfar as possible, that copies in circulation reflect current thinking, please register yourreceipt of an original hard copy and/or interest with:The Bridge Strike Prevention GroupTraffic Signs Policy BranchTraffic Management (TM4)Department for TransportZone 2.8 Great Minster House76 Marsham Street,London SW19 4DRTel: 0207 944 2974email: John.Munns@dft.gsi.gov.ukmarking all communications ‘Protocol for Highway Managers and Bridge Owners’.1.2 Wherever possible, give an email contact address too, as this will greatly simplify theissuing of updates.Further bound copies of the document can be purchased from CSS for £10.00including post and packing. Contact is CSS@Wiltshire.gov.uk.2 Feedback2.1 To ensure full debate on all aspects of dealing with the problem of bridge strikes andso feed the development of the Protocol, please send any comments you have onthe document, or details of other useful related experience you have gained, to thesame contact address in 1.1.2.2 The same contact should also be used to raise issues on any aspect of the detailwithin the Protocol. Queries can then be directed to the most appropriate source.2.3 The current version of the Protocol will be displayed on the DfT website and thiswill be supplemented from time to time with notes on points of interest fromfeedback received.The web address is www.dft.gov.uk36

Prevention of Strikes on Bridges over HighwaysA Protocol for Highway Managers and Bridge Owners2.4 The current issue will also be held on the CSS and Network Rail websites:www.cssnet.org.ukwww.networkrail.co.ukThe latter website also displays the ‘Good Practice Guides for Freight and PassengerTransport Operators and Drivers’ listed in the Bibliography.3. Other useful contacts, as at July 2007(Updates will be listed on DfT website given in 2.3)3.1 CSS Bridges GroupSecretary: Graham ColeSurrey County Councilemail: graham.cole@surreycc.gov.ukBSPG Rep:Tony NorfolkKent County Councilemail: anthony.norfolk@kent.gov.uk3.2 DfT Traffic Signs BranchBridge Strike Prevention Groupemail: John.Munns@dft.gsi.gov.uk3.3 Network RailAll enquiries/reports to:Keith RossTel: 0207 902 3310email: Keith.Ross@networkrail.co.ukWhen contacting Network Rail, to facilitate a prompt response, please note andprovide the details of the bridge involved as shown on the bridge identification plate.3.4 The ESDAL website is www.esdal.com37

Prevention of Strikes on Bridges over HighwaysA Protocol for Highway Managers and Bridge Owners