Case Study:

Sacramento, California

Overview

This case study compares the use of a state-of-the-practice travel demand model and a transportation-land use model to assess regional transportation and land use policies. The results suggest that the land use model captures important feedback relationships not captured by the travel demand model alone.

A multiyear project at the University of California-Davis has compared the use of a regional travel demand model, SACMET96, with two transportation-land use models, MEPLAN and TRANUS, for testing regional transportation and land use policies. The project has evaluated a range of policies, both individually and in combination, including:

High-occupancy vehicle (HOV) lanes;
High-occupancy toll (HOT) lanes;
Light rail transit (LRT) and other advanced transit;
Transit-Oriented Development (TOD);
Roadway-Oriented Development (ROD); and
Pricing.

Impacts were measured for the years 2005 and 2015 on travel, emissions, user benefits, and the spatial distribution of population and employment. The results of the modeling are not always intuitive. Some of the major findings for the Sacramento region include:

Accounting for land use effects can have significant impacts on forecast vehicle-trips, VMT, congestion, and emissions. Travel and emissions impacts were found, in general, to be significantly greater in MEPLAN than in SACMET96 for comparable policy scenarios.
Some policies are synergistic while others may work at odds. For example, transit and pricing policies had little impact individually but a more significant impact in combination. While parking pricing had the effect of reducing trip lengths and VMT, it also provided a disincentive to transit station area development and thus had little impact on mode share.
Similar to transit investments, HOV and HOT policies were found to be much more effective when applied in conjunction with land use and/or pricing policies.
Positive economic user benefits were found for most scenarios. When applied by income group, the user benefit measure could be used to assess the equity implications of each scenario.

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