Bus advance areas have been proposed as a means of reducing delays to buses when negotiating conventional setbacks between the ends of bus lanes and road junctions. They operate by holding non-priority traffic at pre-signals, allowing buses free passage. The first such bus advance area on the approach to a roundabout junction was installed in Doncaster in May 1994. Before and after measurements have shown that the bus advance area has resulted in small reductions in delays to buses (by comparison with a conventional bus lane arrangement) but at the expense of substantial delays to other traffic. This results partly from the necessity to provide a signal stage for side-road traffic to enter the main road traffic to enter the main road at the start of the bus advance area. However, it is estimated that even without the side-road complication delays to non-priority traffic would outweigh benefits to bus passengers. The irregular signal cycle (actuated by a random pattern of bus arrivals) and bunching by the signals of traffic at the roundabout entrance are significant causes of delay. An alternative form of operation is proposed. (A)
Abstract