Advanced LED Warning Signs for Rural Intersections Powered By Renewable Energy (ALERT-1)

In Minnesota, 70 percent of all intersection-related fatal crashes for the period of 2006 to 2008 occurred at rural, through/stop intersections [1]. The Minnesota Department of Transportation identified improving the design and operation of intersections as a critical emphasis area in the Minnesota Comprehensive Highway Safety Plan [2]. At these intersections, sight restrictions caused by vertical and horizontal curves negatively affect a driver's ability to safely accept a gap in the traffic stream. This report presents two year study results on the development of a new intersection warning system referred to as an Advanced LED Warning System (ALWS) and evaluation of the system's effectiveness. The ALWS was developed to address the sight restrictions in rural through/stop intersections, and it consists of vehicle detectors that detect approaching or stopped vehicles and LED warning signs that respond according to the received messages from the detectors. The LED signs have LEDs on the perimeter of the sign and a warning message in the middle, which is commonly referred to as a blinker sign. For easy installation, all signs and detectors are powered by solar panels and batteries. All message communications between the detectors and signs are performed through wireless transceivers. Wireless communication avoids potential problems associated with buried wires, i.e., wire breakages, short circuits, difficulty of replacement, and monthly power bills. In order to evaluate this new sign technology, the intersection of West Tischer Road and Eagle Lake Road in Duluth, Minnesota was chosen. West Tischer Road is the main road with a through condition while Eagle Lake Road is the minor road with a stop condition. The Annual Average Daily Traffic (AADT) for West Tischer Road is 980 vehicles per day. The AADT for Eagle Lake Road is 550 vehicles per day. The number of daily entering vehicles is 760 vehicles per day [6]. This intersection was selected because of a severe vertical curve on the east approach of West Tischer Road. This vertical curve significantly reduces the available intersection sight distance for vehicles stopped on either the north or south approaches of Eagle Lake Road thereby requiring these vehicles to blindly accept gaps in the westbound traffic stream. Conversely, vehicles traveling westbound on West Tischer Road cannot see cross traffic at the intersection until they are nearly in the intersection. The ALWS for this intersection consists of three blinker signs and four vehicle detectors. The blinker sign for the main approach …