Field Evaluation of Pilot Vehicles and Portable Traffic Control Signals With and Without a Flagger

The national Manual on Uniform Traffic Control Devices (MUTCD) does not prohibit the use of a pilot vehicle in conjunction with portable traffic control signals (PTCSs), but it does require that a flagger be stationed on the approach to the activity area where a pilot vehicle is being used. This negates the main advantage of using PTCSs—the removal of the flagger from the transition area. To assess compliance with pilot vehicles and PTCSs with and without flaggers, field studies were conducted at lane closures on two-lane, two-way roads in Texas. Only 2.7% and 2.3% of drivers did not comply with the PTCSs and pilot vehicle for both conditions studied (with and without a flagger, respectively). The similar violation rates between treatments showed that there was no significant or practical difference between violations at a PTCS with and without a flagger when a pilot vehicle was used. The overall recommendation is that the national MUTCD be changed to allow the use of a pilot vehicle in conjunction with PTCSs without a flagger at lane closures on two-lane, two-way roadways. In an effort to provide pilot vehicle drivers, especially those with less experience, an initial estimate of the minimum green time needed to clear the vehicle queue at the PTCS, an easy tool was developed.