Field Evaluation of Work Zone Speed Control Techniques

The results of field studies conducted in Texas to evaluate selected methods of slowing work zone traffic to acceptable speeds are presented. The studies were performed at six work zone sites, including two rural freeway sites, one urban freeway site, one urban arterial site, and two rural highway sites. The following work zone speed control methods were studied: flagging, law enforcement, changeable message signs (CMSs), effective lane width reduction, rumble strips, and conventional regulatory and advisory speed signing. The study results indicate that flagging and law enforcement are effective methods for controlling speeds at work zones. The best flagging treatment tested reduced speeds an average of 19 percent for all sites, and the best law enforcement treatment reduced speeds an average of 18 percent. In contrast, the best changeable message sign and effective lane width reduction treatments tested each reduced speeds by only 7 percent. An innovative flagging procedure, a police traffic controller, and a stationary patrol car were found to be the most effective treatments on most highway types. A circulating patrol car and rumble strips were found to be ineffective treatments for controlling work zone speeds. Although conventional regulatory and advisory signing was found to be ineffective in reducing work zone speeds, conventional speed signs are an essential component of any work zone speed control effort.