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T.P.D.M. V.2.5
(Al/2002)
5.4.5 Rumble Areas
5.4.5.1 Rumble areas are patches of rough coarse road surface which produce aural and tactile stimuli
inside a vehicle with the intention of alerting drivers to a particular hazard ahead.
5.4.5.2 Research in the UK TRRL Report 800 has however indicated that although these devices may
reduce the number of accidents occurring at a particular hazard they do not necessarily reduce
the approach speed of vehicles, and therefore if the latter is required these type of devices may
not be appropriate.
5.4.5.3 Appropriate material for the patches has found to be 13-19mm roadstone set onto the road
surface using epoxy resin, and further details of this can be found in TRRL Report 800.
5.4.5.4 Six patches should normally be used to form the complete rumble area, which should normally
end at least 100m before the hazard.
5.4.5.5 Rumble areas are generally only appropriate for two way 2-lane carriageways because of possible
dangers that might occur with vehicles overtaking and simultaneously passing over the patches,
however they have been used in other countries on a dual carriageway approach to a round about.
5.4.5.6 It is only necessary to lay patches on the approach lane to the hazard and not the full width of the
carriageway or carriageways as vehicles in the opposite direction are proceeding away from the
hazard. However this can in the case of single carriageway roads sometimes lead to vehicles
crossing over onto the adjacent lane for opposing traffic in order to avoid the rumble areas, and
therefore care has to be taken as to the siting of rumble areas that there is adequate visibility.
Alternatively it maybe appropriate to consider the use of double white lines to confine vehicles to
their lanes.
5.4.5.7 The precise method of determining the length of the patches and the spaces between can be
found in TRRL Report 800, which assumes a linear decelaration between points 250m and 100m
before the hazard and calculating the positions and lengths of the patches accordingly. However
conditions in the Territory are such that uniform speeds can generally be assumed. Based on this
assumption Table 5.4.4.1 gives the length of the patches and spaces between them for various 85
percentile approach speeds.
Table 5.4.4.1
Patch Lengths and Spacing
85 percentile speed
km/h
Patch Length
m
Space between patched
ffi
Rumble strip Length
IB
i
60
5.69
10.96
100
70
7.08
12.36
116.64
80
8.47
13.75
133.3
90
9.9
15.1
150