Travel Demand Models

Travel demand models predict future demand in a roadway network based on analytical relationships of trip generation, destination choice, mode choice, time-of-day travel choice, and route choice.   These models are typically used to predict the impacts of major highway improvements in metropolitan areas, e.g., a new highway facility. Today, travel demand models are used in more wide-ranging tasks, including development of transportation master plans, evaluation of proposed land-use changes, initial design of transportation facilities, and evaluation of air quality impacts. However, these tools were not designed to evaluate travel management strategies, such as ITS, ICM, and operational strategies. Travel demand models have only limited capabilities to accurately estimate changes in traffic performance (such as speed, delay, and queuing), resulting from implementation of these operational strategies, because of the poor representation of the dynamic nature of traffic in travel demand models. Examples of travel demand modeling tools available in the I-210 corridor models include the SCAG Regional model (implemented in TRANSCAD) and the local Pasadena model (implemented in VISUM).