This paper describes an innovative pedestrian modeling technique known as Space Syntax, which was used to create estimates of pedestrian volumes for the city of Oakland, California. These estimates were used to calculate pedestrian exposure rates and to create a Relative Risk Index for the city’s first pedestrian master plan. A major challenge facing planners, transportation engineers, and pedestrian-safety advocates is the lack of detailed and high quality pedestrianexposure data. Exposure is defined as the rate of contact with a potentially harmful agent or event. Pedestrian exposure is therefore defined as the rate of pedestrian contact with potentially harmfully situations involving moving vehicles (e.g., crossing an intersection). Pedestrian risk is defined as the probability that a pedestrian-vehicle collision will occur, based on the rate of exposure. To estimate exposure, pedestrian volume measurements must be made, but such measurements not easily available. In the absence of accurate exposure data, pedestrian-safety decisions are often made by estimation, rules of thumb, or political influence, resulting in mixed and potentially less effective outcomes. This paper also explores the value of the Space Syntax volume-modeling approach for generating estimates of pedestrian exposure, using the City of Oakland as a case study. It discusses the method’s theoretical background, data requirements, implementation, and results. The author suggests that the output of the model - city-wide pedestrian volume estimates - is useful to pedestrians, planners and transportation engineers, and he discusses the value of the pedestrian-exposure concept for the planning professional.
December 11, 2003