Pedestrians in Regional Travel Demand Forecasting Models: State of the Practice

It has been nearly 25 years since non-motorized modes and non-motorized-specific built environment measures were first included in the regional travel demand models of metropolitan planning organizations (MPOs). Such modeling practices have evolved considerably as data collection and analysis methods improve, decision-makers demand more policy-responsive travel forecasting tools, and walking and cycling grow in popularity. As MPOs look to enhance their models’ representations of pedestrian travel, the need to understand current and emerging practice is great. This paper presents a comprehensive review of the practice of representing walking in MPO travel models. Based on a review of model documentation, it was determined that – as of mid-2012 – 63% (30) of the 48 largest MPOs include non-motorized travel in their regional models, while 47% (14) of those also distinguish between walk and bicycle modes. The modeling frameworks, model structures, and variables used for pedestrian and non-motorized regional modeling are also described and discussed. A survey of lead MPO modelers revealed barriers to modeling non-motorized travel, including insufficient travel survey records, but also innovations being implemented, including smaller zones and non-motorized network assignment. Finally, best practices in representing pedestrians in regional travel demand forecasting models are presented and possible future advances are discussed.