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Local road mountable roundabouts - are there safety benefits?

Candappa, N L

Road Environment

ARSC conference 2015

_x000D_Intersection crashes are a significant source of death and injury, locally and worldwide. While they are of great importance within the road network due to their role in facilitating movement of different roadusers in conflicting directions, and change of travel direction, both these roles can create a naturally high potential for crashes, intersections found to be three to four times less safe than midblocks, (AustRoads, 2010). Crashes at intersections are also a persistent problem, with crash percentages at intersections remaining relatively constant over the years (Hoareau, Candappa, & Corben, 2009), producing injuries of high severity. _x000D_

_x000D_Initiatives to improve safety at intersections include the use of mountable roundabouts on local roads. Similar in design to the traditional roundabouts, mountable roundabouts have the advantage of being more readily incorporated at restricted intersection geometries, the mountable central island allowing larger vehicles to mount the island to account for tight turning circles. The design is less likely to require widening of the intersection, reducing construction costs significantly. The design is worthy of further consideration given its potential for local councils to address safety issues at intersections in a more cost effective manner. _x000D_

Though not necessarily a new concept, little information is available on the design's efficacy. A preliminary case study by MUARC of two such roundabouts on local roads investigates whether these designs provide any safety benefits. The design features are explored with respect to impact on approach speed, impact on overall speed environment and kinetic energy, impact angle, and road user behaviour.