Shared Space: Measuring the Boundaries and Assessing the Efficiencies

Shared space is a design concept becoming increasingly common in European countries. It intentionally blurs pedestrian-driver boundaries in order to reduce vehicle speeds, create more walkable areas, and improve aesthetics and sense of place. What constitutes a shared space is not clearly defined in the existing literature. Steps toward a systematic method for assessing a space’s “level of sharedness” have been developed in this research to minimize the present ambiguity. A paradox of shared space, suggested by numerous observers but little studied, is that while allowing freer pedestrian movement, shared space also appears to promote greater vehicle efficiency than conventional traffic control systems. This study also investigates the shared space paradox. Pedestrian and vehicle characteristics and behaviors were measured for a range of shared spaces in five different countries, including the United States. Traffic analysis software was then used to determine the expected vehicle delay at intersections with traditional control systems and the same number of pedestrians, vehicles, and lanes as the shared spaces. The measured vehicle delays at the shared spaces were found to be considerably lower than the expected vehicle delays at comparable intersections using traditional control systems. The low vehicle delays at the shared spaces are attributed to low vehicle speeds, which, in turn, lead to more seamless and efficient pedestrian-vehicle interactions, and considerably less stop-and-go vehicle behavior. The study results suggest that shared space can provide much greater vehicle capacity than conventional intersections, while also better accommodating pedestrians. If intersections using traditional control systems were to offer the same vehicle capacities as shared spaces, more vehicle lanes would likely be necessary. This would, in turn, result in places that are significantly less supportive of urban life and pedestrian activity