Land use models in project-level traffic forecasting
Several major metropolitan areas in the US have integrated land-use models into their travel forecasts. The latest generation of land-use models require extensive and spatially-detailed data on the economy of the region. A well-functioning land-use model will forecast the spatial distribution of population and employment by economic sector.
These models are expensive and time-consuming to set up and calibrate. Land-use models are especially important for regions that are rapidly developing and are testing major alternatives to greatly improve highway and transit accessibility to parts of the region that are now less intensively developed. However, land-use models have not undergone the level of validation as have traditional four-step travel forecasting models, so there is still considerable uncertainty in the planning community as to the quality of those forecasts. It is very important that an analyst be advised by outputs of land-use models, where available, but land-use models are of only limited value for project-level travel forecasting.