At intersections and other potential traffic conflict points, raised safety platforms can be used to promote lower vehicle speeds to reduce the likelihood and severity of collisions. Most commonly, this treatment is used where pedestrians and/or cyclists interact with motorised vehicles to improve the safety of vulnerable road users. One type of raised safety platform is the wombat crossing, which focuses on pedestrian safety, and has been previously described on our website. However, other types of raised safety platforms are seen increasingly in both urban and sometimes also rural contexts. Raised safety platforms are a primary safe system treatment and can be relatively low cost and easy to install compared with other ‘more transformative’ treatments.
Effectiveness
Raised safety platforms are vertical deflection devices, with the slope or angle of approach and departure ramps influencing their effectiveness for a range of roadway and traffic characteristics. While design and implementation vary, the Austroads Guide to Road Safety documents demonstrated casualty crash reductions of 40 - 50% at Australian sites. One study in Victoria also observed a 13km/h reduction in 85th percentile speeds through an intersection following the installation of the treatment[1]. As with other infrastructure treatments designed to reduce speeds, safety performance is supported by appropriate signs, guidance and signals on approach.
Specification
Close attention must be paid to the severity of the ramp slopes so that the desired effect is achieved without unduly disrupting the comfort and controllability of vehicles of different types. Different specifications are advised for different speed zones. For example, advisory speeds of 40 – 50km/h may be appropriate at the platform for 60km/h speed zones, while 20km/h may be advised for speed zones of 50km/h or less. This is important to consider where pedestrians might be impacted, as 30km/h is generally considered a survivable impact speed for those road users.
Other considerations
Late braking ahead of raised platforms has been observed in some cases and can potentially lead to rear-end crashes. However, Austroads notes that this is most evident at newer installations and ‘there is no tangible evidence of significant safety concerns’. Also noted is the need for more detailed evaluations regarding specific impacts on different road user groups, vehicle types and related services.
[1] Information sourced from Austroads Guide to Road Safety Part 2.