Expanded warrants for unsignalised intersection turn treatments

Austroads (2013) Guide to Traffic Management details warrants for the selection of turn treatments (i.e. basic, auxiliary lane and channelised) on the major road at unsignalised intersections. The methodology behind these warrants was first presented in Arndt & Troutbeck (2006) and is based on an economic comparison of the turn treatment upgrade cost and the relative crash benefits of an increased level of protection for turning vehicles. The use of these warrants for a number of years has inevitably led to queries regarding application in situations not explicitly discussed in Austroads (2013). Arising from these, the QLD Department of Transport and Main Roads (TMR) identified the need for additional warrants to address some of the more common queries. This paper provides a summary of the development of additional warrants for a range of situations and makes recommendations on these for inclusion in future versions of Austroads (2013). TMR has already adopted these warrants in the Road Planning and Design Manual (Transport and Main Roads 2014).