Handling Non-Motorized Trips in Travel Demand Models

Abstract

Non-motorized modes of transport as agents of sustainable mobility have received increased attention, and the need to account for them in travel-demand models has long been recognized. Non-motorized trips are generally short trips, and in macroscopic models, many of them end up in the same traffic-analysis zone. Intrazonal trips are, however, rarely modeled very precisely, mainly due to the spatial aggregation problem of macroscopic models, which renders it difficult to estimate intrazonal impedances for demand calculation. Two possible ways to mitigate the intrazonal problem for non-motorized modeling include (1) enhancing the modeling of intrazonal trips, a process which requires the estimation of intrazonal impedances as a first step and (2) avoiding intrazonal trips, which requires a reduction in zone sizes. Aft er providing a background to the modeling of non-motorized trips, the chapter describes ongoing research efforts aimed at enhancing the treatment of non-motorized trips in regional travel-demand models. The outcome of the research is expected to improve the capabilities of planning agencies in incorporating non-motorized travel in their travel-demand models.