A driving simulator study to evaluate the impact of portable changeable message signs (PCMS) on driver speed characteristics

This research project examined the effects of sequential Portable Changeable Message Signs (PCMS) on driver behavior in work zones. PCMS are temporary traffic control (TTC) devices, part of Intelligent Transportation Systems, which supplement static signs to provide advance warning and real-time information to drivers. Text and number based messages are displayed on the PCMS for which detailed evaluation has not been carried out before. This research fills this gap using a driving simulator (DS) supplemented by objective and subjective surveys. A work zone on I-44 in rural Missouri was replicated in the DS using video recordings and GIS (Geographical Information System) data. The DS experiment consisted of five scenarios (0-4). The control scenario (scenario-0) was compared to scenarios 1-4. In the DS, evaluation of the four message signs displayed on the PCMS used by the Missouri Department of Transportation (MoDOT) and their effects on drivers\u27 speed was carried out. The results from the experiment showed significant decrease in speed of driver as a result of the type of messages displayed by the PCMS. From the objective analysis results, message sign-4 (MS-4) saw the maximum decrease in the speeds of drivers when compared to the control scenario. The subjective (survey) results showed that MS-2 was the most preferred message as it displayed a specific speed limit for the participants to follow. Also, the 85th percentile speeds before the construction zone closely matched with the displayed speed for MS-2. The results obtained from the subjective survey reinforced the fact that PCMS were effective in reducing the speed of the drivers --Abstract, page iii