Quantifying suppressed child pedestrian and bicycle trips

Abstract

Traditional pedestrian and bicycle safety analyses take a reactive approach to traffic safety by investigating crashes, injuries, or fatalities after they occur. Also examining trips that have been suppressed because of perceived road safety concerns facilitates a more proactive safety approach; however, a methodology must first be developed to estimate the number of pedestrian and bicycle trips that are suppressed specifically due to road safety concerns. To accomplish this, we examine child pedestrian and bicycle trips to and from schools in Denver, Colorado. By combining suppression rates derived from a survey examining parental perceptions of safety and the upper limit of trip frequencies derived from a GIS network analysis, we explore how grade level, gender, and adult supervision are related to childhood travel allowance in terms of street-level design characteristics such as posted speed limits, vehicle volumes, presence of sidewalks and bike lanes, and the number of vehicle lanes. We then investigate how widespread these suppressed trips are by quantifying the number of children that are impacted and how their routes are altered. Finally, we detect built environment characteristics – such as street-level designs, network configurations, barriers, and destination siting – linked with high levels of suppressed trips. By integrating this tool with traditional traffic safety analyses, we hope to not only make the places where children are currently walking and bicycling safer, but to improve safety in places where children should walk and bike.