Preferences for roundabout attributes among US bicyclists: A discrete choice experiment

As roundabouts become increasingly common, there is very limited research about bicycle safety at roundabouts and, specifically, a lack of information about preferences for roundabouts among people bicycling. To address this gap, we conducted a discrete choice experiment involving an online survey of 613 US adult bicyclists to understand stated preferences for roundabouts with different design and operational characteristics: central island size, number of circulating lanes, bicycle facility type, motor vehicle volumes, and approach speed limit. For each respondent, the experiment included six (from among 18) choices between two roundabouts with different attributes, represented using text and simulated images. We analyzed these data using panel mixed multinomial logit models with random and systematic preference heterogeneity due to respondent characteristics. Overall, US bicyclists seem to prefer roundabouts with: smaller central islands, fewer travel lanes, lower traffic volumes, lower speed limits, and separated bicycle lanes; although, shared lane bicycle markings and signs were also preferred over bicycle ramps to the sidewalk or no bicycle facilities. Additionally, there were significant variations in preferences for bicycle facilities at roundabouts. Women, infrequent cyclists, and "interested but concerned" cyclists had stronger preferences for separated bicycle lanes, but "strong and fearless" and/or "enthused and confident" cyclists had significantly weaker preferences for these more protected facilities. This research offers insights into bicycling preferences that may help to create roundabouts that are safer and more attractive for people bicycling of all ages and abilities.