Drivers Stopping Behaviour at Non-Warranted Stop Signs: A Feasibility Study

Author(s): Gabriel Suskin, Neville Suskin
Student Paper Competition: Honourable Mention

Slidedeck Presentation:



36% of fatal crashes occur at stop sign intersections and pedestrian injury is the third leading cause of injury-related deaths among children ages 5 to 14. Driver's stopping behaviour at non-warranted (installed to control speed and not right-of-way) 3-way stop signs, that are common in neighbourhoods, may be suboptimal according to our municipal traffic department. To assess: 1) whether stopping behaviour could be explored under real life but experimental conditions; 2) whether the presence of a pedestrian (especially a young pedestrian) on the sidewalk at the intersection, affected driver's stopping behaviour. Using a non-warranted 3-way stop sign near our neighbourhood school, an observer vehicle was parked approximately 20 metres from the 3-way stop-sign intersection on the minor street adjacent to a house. The intersection was clearly visible from the observer vehicle. The authors observed the stop sign for the control. One observer recorded stopping behaviour for each of the treatment conditions. There were 3 treatment conditions: Treatment 1 comprised an adolescent male pedestrian (author aged 15); treatment 2 comprised a young male pedestrian (assistant aged 32), and treatment 3 comprised an older male pedestrian (author aged 55). The pedestrian waited on the sidewalk at the stop sign while the vehicle approached. 60 cars were observed for the control (greater 'n' to evaluate additional variables not reported here) and 45 cars were observed for each of the treatments. Drivers had to come to a complete stop for approximately 1 second to be counted as a stop and stopping behaviour was only counted if that driver was the only driver at the intersection and was traveling on the major road without turning. Simple proportions and odds ratios (O.R.) using chi-square analyses were performed using CDC Epi-Info Statcalc In the absence of pedestrians 26 of 60 (43.3%) of drivers stopped at the stop-sign . The presence of ANY pedestrians vs. NO pedestrians was associated with more (35 of 45) drivers stopping (77.8% vs. 43.3%, O.R. 4.5, p<0.001). The presence of a teenaged pedestrian vs. NO pedestrians was associated with the highest proportion (43 of 45) of drivers stopping (95% vs. 43.3%, O.R. 18, p<0.001). The presence of a teenaged pedestrian vs. YOUNG adult or OLDER ADULT pedestrian was associated with more drivers stopping (95% vs. 70%, O.R 6, p=0.002). The presence of a YOUNG ADULT pedestrian vs. OLDER ADULT pedestrian was not associated with higher proportion of drivers stopping (66.7% vs. 73.3%, O.R.=0.7, p=0.49). It appears feasible to experimentally manipulate conditions to explore real-life stopping behaviour of drivers at a non-warranted neighbourhood stop sign as we observed substantially different proportions of drivers stopping between a control condition without pedestrians compared to experimental conditions with pedestrians (especially with a teenaged pedestrian). Less than half of drivers stopped in the absence of pedestrians. This proportion increased substantially (to 95%) when a teenaged pedestrian was present. Almost a third of drivers did not stop for young or older adult pedestrians. While definitive research using valid measures and sampling techniques are needed to confirm real-life driver's stopping behaviour at non-warranted neighbourhood 3-way stop signs, our study suggests that drivers stopping behaviour is acceptable only in the presence of young (teenaged in our case) pedestrians.