Slope stress criteria as a complement to traffic stress criteria, and impact on high comfort bicycle accessibility

A high-comfort bike network that connects people's homes with their destinations is crucial to attracting more people to cycling. While avoiding high traffic stress is one critical dimension of comfort, another is avoiding steep climbs. In this study, we propose “Steepness Level” criteria that can complement Level of Traffic Stress criteria for evaluating bike networks, drawing from best-practice guidelines and behavioral studies that show tradeoffs cyclists make between steep grades and additional distance. We then apply these criteria to Montreal's bike network, along with Level of Traffic Stress criteria, to determine the impact of considering steepness limitations on bike accessibility. For some situations, adding steepness limitations has a small impact on accessibility while in others, it makes many neighborhoods inaccessible that, based on traffic stress alone, would be considered accessible. And where the topography creates a natural barrier (a ridge) with a single gently sloped corridor passing through, we demonstrate that applying low-traffic-stress treatments in this corridor would increase the fraction of central Montreal that is accessible by bike from 33% to 50%.