Delays at Freeway roadworks: safety and road user cost considerations

Abstract

Freeway incidents are events which result in a temporary reduction in the capacity of the facility. Intelligent transport systems developments are primarily concerned with ‘random’ freeway incidents such as breakdowns, crashes, spilled loads etc. In contrast, relatively less attention has been given to ‘planned’ incidents such as maintenance activities. As part of a study aimed at predicting the delays associated with freeway incidents, this paper deals with issues associated with delays at major roadworks. A variety of data was collected as part of a case study of a major maintenance project on Melbourne’s M1 motorway. Vehicle delays were measured using a timed number plate survey. During periods of heavy delay, a number of vehicles were observed to execute illegal turns to avoid the traffic delays at the roadworks. There is evidence of a relationship between the occurrence of this behaviour and the corresponding level of delay at the roadworks. Road user delay costs were also estimated as part of the study. The potential role of an analytic delay model in maintenance planning is explored. This paper is to be presented at the 19th ARRB TR Conference to be held in Sydney, 6-11 December 1998.