Evaluation of End-of-Queue Crash Mitigation Strategies at Flagging Stations on Two-Lane Roads

The objective of this research project was to identify and evaluate strategies to mitigate end-of-queue crashes at flagging stations on two-lane roads. The research team evaluated the following treatments based on feasibility and advantages of each treatment:

• Install light-emitting diodes (LEDs) or a warning light on the static BE PREPARED TO STOP (BPTS) sign.
• Switch to a portable changeable message sign (PCMS) in lieu of the static BPTS sign.
• Use a portable traffic signal (PTS) in lieu of the flagger at flagging operations.

Researchers collected speed profile data of decelerating vehicles at 18 sites across Texas for the baseline (static BPTS sign) treatment and one or more other treatments. The results did not show any meaningful differences between mean speeds of baseline treatment and the BPTS sign with LED lights, BPTS sign with a warning light, or PCMS. Differences were detected when a PTS was used in lieu of a flagger, but only a limited amount of data was available for analysis. Researchers conducted a benefit-cost analysis, which only included capital costs, operation and routine maintenance costs, and transportation costs, when available. Cost savings of utilizing PTSs in lieu of flaggers were realized in just 2 years. However, more research is needed to determine its effectiveness in reducing end-of-queue crashes at flagger stations.