Should this become a street or a road? The design up/design down choice matrix

Purpose At very slow speeds and in dense environments, street-style integration appears relatively seamless with strong safety track records despite high levels of mode mixing. In higher speed roadways, extensive sheltering and clear mode segregation appears to generate equally safe outcomes. Between these two extremes, safety outcomes for both vehicles and vulnerable users are less than ideal. As existing facilities are re-evaluated for complete streets redesign, there is a desperate need for guiding principles and predictive data that can help the designer and local policy makers determine whether to use an integration or sheltering strategy for the nonmotorized users the community wants to support. Design/methodology/approach An analysis of crash history was coupled with attention and movement data tabulated from the SHRP2 NDS to understand how specific contextual features impacted both the precursors for crashes (attention, speed and responsiveness) and crash history itself. Findings This project summarizes the design and retrofit implications of a 4-year NDS based project (the FDOT Mental Frameworks project) that generated psychological principles for designing an integrated space. An overview of this project sets up the distinction between an integrated street and a roadway sheltering strategy. Specific benchmarks are provided to delineate the boundary conditions between streets, roads and the uncomfortable hybrids that sit between them. Research limitations/implications This is a vulnerable user safety retrofit strategy based on the psychological limitations and behavioral patterns identified in the FDOT Mental Frameworks project. Practical implications The benefit of this strategy is that it is based on the driver’s psychological and perceptual limits, accounting for the ways that the resulting behavior patterns impact what can be realistically expected from the typical range of facility interventions. Its goal is to provide appropriate, achievable, incremental modifications to existing systems to forward vulnerable user safety. It is not intended as a network (re)balancing strategy, although it may assist with those efforts. Social implications Significant time and effort are often expended in a wishful attempt to simultaneously satisfy multiple competing user groups within individual facilities. This strategy grounds the safety remediation process in the realities of human perceptual limitations, which will help decision makers save time, money and credibility. Originality/value A decision flowchart is presented to guide designers as they identify whether a facility can become a street or must be treated as a road, along with the specific intervention strategies that can be used to improve vulnerable road user safety.