Driver adaptation to a new two-lane roundabout

Abstract

The first two-lane roundabout in New Brunswick opened in Fredericton on September 2015. The roundabout development raised significant safety concerns given the unfamiliarity that local drivers had with using two-lane roundabouts. The project provided a unique opportunity to study driver behaviour and how it changed over time as drivers became more familiar with its operation. Video footage was collected at approximately 1-month intervals for a year through the use of an unmanned aerial vehicle (UAV) to extract driver error information. The most commonly observed driver errors by rank were 1. changing lanes within the roundabout, 2. drivers not yielding to traffic already in roundabout, 3. improper lane usage, 4. stopping within roundabout, 5. not giving right-of-way to trucks, and 6. left-turns. The overall rate of driver errors fell by 67% within the first 15 weeks following opening and remained fairly consistent thereafter. Operational analyses were completed which indicated that the default critical and follow-up headway values used by HCS 2010 underestimate driver behaviour relative to gap-acceptance. New critical and follow-up headway values were developed based on video analysis to better reflect local driver characteristics.