Conducting In-service Road Safety Operational Reviews of Temporary Traffic Control in Work Zones

Work zones present unique traffic operations challenges for everyone involved, the road user, the contractor, and the owner of the road. For example, drivers expectations can easily be mislead by the complexity of a temporary traffic control (TTC) set-up in a work zone. This can result in an increase in the perception reaction time of drivers to as much as 4.5 to 5.0 seconds, a significant increase from the 2.5 second perception-reaction time used in road design. This is one of the reasons that work zones can be dangerous for motorists, pedestrians, and workers. Approximately 1100 fatalities occurred in 2001 in work zones in the United States. Alberta had two fatalities and 133 injuries in work zones in 2001. This paper reviews the need for, and discusses how to conduct, in-service road safety operational reviews of temporary traffic control in work zones. Presently there are no Canadian guidelines for determining when and how to conduct inservice road safety operational reviews of TTC in work zones. The Transportation Association of Canada (TAC) has recently released the 100% draft for the “Canadian Guide to In-service Road Safety Operational Reviews”, however, TTC was not included in the scope for the development of these guidelines. Many of the techniques and methods that are outlined in the TAC guidelines are not applicable to conducting an operational review of TTC. This arises mainly from the fact that TTC set-ups are usually only in place for short periods of time. Inservice road safety reviews of TTC set-ups do not often have any background collision and operational data to analyze and the actual review must be conducted very quickly. The time required to conduct a safety review on an existing road is often measured in weeks if not months, the time to conduct a safety review of a TTC set-up should be measured in days. This paper reviews the need for a formal procedure for conducting in-service road safety operational reviews of TTC set-ups and discusses the methodology of conducting such reviews. This includes network screening / project selection, data requirements, review procedures and drafting the final report. Some of this methodology is currently being given by the Alberta Construction Safety Association in the Alberta Temporary Traffic Control short course, which outlines best practices with respect to designing, installing, maintaining and inspecting TTC set-ups. The focus of this paper is to provide information on conducting safety reviews of TTC set-ups in work zones.