In a joint research effort to reduce collisions in highway work zones, the U.S. Department of Transportation Joint Program Office and Federal Highway Administration (FHWA) contracted the University of Michigan Transportation Research Institute to initiate a work zone collision avoidance research project using ITS technologies. A new concept using a wireless sensor network was developed to address the speed differential problem around work zones, a problem implicated in many rear-end crashes. A prototype queue-warning system, which alerts drivers approaching slow moving traffic ahead, was proposed and investigated. The core element of the system is a smart barrel- an ordinary appearing traffic-control barrel containing an inexpensive speed sensor, a simple, adjustable warning signal, and wireless communication capability to a central controller. This study investigated two elements of the system: an inexpensive speed sensor and a simple signaling system. Three prototype speed sensors were developed and evaluated in a limited field study using active infrared, passive infrared, and magnetic sensor technologies. The active infrared system was most accurate, but consumed most power while the passive infrared system was as accurate and required the least power. Simple signaling schemes were also prototyped and presented to drivers in a pilot experiment using a driving simulator. Both subjective opinions about the utility of the system and objective measures of driving performance were collected. Results suggest that drivers found the adaptive queue-warning systems more helpful than static road signs, and altered their driving performance in a way that suggests increased safety with the queue-warning systems.
Samenvatting