1 - HKU Libraries

T.P.D.M.V.2.3
(Al/2001)
3.4.7.7 For Rural Trunk Roads the same considerations as given to Urban Trunk Roads apply to the
central reserve width, with the exception that the marginal strips should be increased to a
minimum width of not less than 1000mm. The minimum provisional central reserve width
for a Rural Trunk Road, having concrete profile barriers incorporating lighting columns will
therefore be 3200mm, subject to the detailed arrangements for mounting the lighting
columns and gantry signing Planting in the central reserve of a Rural Trunk Road should be
viewed with caution because of the high traffic speeds that can be generated and the
maintenance problems and difficulty of access that can result. However if such planting is
considered appropriate a central reserve width of at least 4000mm will be required. Most
traffic signs should be able to be accommodated within the 3200mm minimal width without
the necessity for further widening.
3.4.7.8 On District and Local Distributor Roads and Rural Roads having dual carriageways the
width of the central reserve will vary according to the particular circumstances of the route.
However in those situations where a concrete profile barrier incorporating lighting columns
is considered appropriate marginal strips not less than 300mm wide must be provided
adjacent to the barrier. Based on the provision of concrete profile barriers and lighting
columns a minimum provisional width for the central reserve may be taken as 1700mm,
subject to the detailed arrangements as to mounting requirements for the lighting columns.
If planting in the central reserve is required the minimum planting width provided should
not normally be less than 1000 mm wide, and it may be appropriate for amenity reasons to
replace the concrete profile barrier with a suitable dwarf wall and kerbs. The marginal
300mm strip should however be retained. Where a concrete profile barrier or other barrier
is not considered appropriate or necessary paragraphs 3.4.7.2 and 3.4.7.3 will be relevant in
respect of the widths for the central reserve. If traffic signs are required to be erected on the
central reserves of this type of road the minimum provisions of paragraph 3.5.2.1 must at
least be attained.
3.4.7.9 Consideration should also be given when determining the widths of central reserves as to the
future requirements, if any, of fixed track mass transit systems and elevated road structures.
3.4.7.10 Careful attention should be given to the termination of central reservations and traffic
islands particularly where turning movements may take place, and adequate road markings
and signs in accordance with Volume 3 must be provided in order to direct vehicles past the
islands or reservations. For details of barrier fences, refer to Highways Department
Standard Drawings.
3.4.7.11 If refuge islands are provided for pedestrians at junctions a minimum width of 4.5 m should
be provided on the exit carriageway and 3.8 m on the entry carriageway. The latter may
need to be increased to 4.5 m if there is a high percentage of heavy goods vehicles.
Additionally as shown in Diagrams 3.4.7.1 and 3.4.7.2 the nose of the islands should not
generally be closer than 3 m to the line of kerbs of the other road forming the junction.
3.4.7.12 Parking should not be permitted in the vicinity of traffic islands or refuges at junctions. It is
not only because of the danger of masking pedestrians crossing the road but also it can result
in vehicles running over the island when manoeuvring past parked vehicles and negotiating
the junction, causing damage to street furniture or danger to pedestrians waiting on the
island. In many cases it may be necessary to introduce stopping restrictions in the vicinity
ofj unctions.