Samenvatting
The report describes the surveillance of each off-ramp in California using a counter and camera developed by California Department of Transportation engineers. These counters used a pneumatic road tube to detect the vehicle, electronic circuitry to identify the wrong-way move, and a small single frame camera to verify the wrong-way move. Wrong-way entries into off-ramps were found to be extremely high at some locations. Some as high 50 to 60 entries per month. Successful reductions in wrong-way entries were accomplished by placing the DO NOT ENTER wrong-way signs at the decision point of each likely wrong -way approach and lowering them to 2 feet (o.6m) above the pavement.