Regional Travel Demand Model

To support the metropolitan transportation planning activities and decision making process AMBAG staff develops, maintains and applies a Regional Travel Demand Model (RTDM). The AMBAG RTDM has been peer reviewed and meets best practice standards. A Federal Highway Administration (FHWA) sponsored TMIP peer review was conducted in 2013 to review the newly updated AMBAG model and discuss future model needs and improvements. The Metropolitan Transportation Plan (MTP) determines what transportation projects are programmed into the RTDM. The current RTDM reflects transportation projects adopted by the AMBAG Board of Directors in June of 2018.

AMBAG by federal mandate is required to maintain two major planning documents: the Metropolitan Transportation Plan (MTP) and the Metropolitan Transportation Improvement Plan (MTIP). These two plans and other AMBAG transportation studies rely heavily on the Travel Demand Model for predicting the impact of travel growth and evaluating potential transportation improvements. The Travel Demand Model comprises a large number of data files in order to represent the many facets of the transportation environment. These data sets provide assumptions on population, employment, income, roadway and transit networks and transportation costs. Using this data the model estimates:

  • Traffic congestion
  • Freight traffic
  • Passengers riding existing and future transit services
  • Greenhouse Gas (GHGs) emissions analysis by automobile

2018 Regional Travel Demand Model
The 2018 RTDM is a technical update only to the 2014 RTDM. The technical update to the 2018 RTDM uses a new base year of 2015 to incorporate land use and transportation network changes. The 2015 base year was not re-estimated, re-calibrated, or re-validated. The 2014 RTDM was an entirely new travel demand model estimated and calibrated to 2010 conditions using data from the 2010-11 California Household Travel Survey (CHTS), Census, employment, and traffic counts data. The model utilizes advance techniques to capture travel behavior at a more individual-level and incorporates disaggregate level data into some of the modeling stages. The primary reasons for introducing more disaggregate level data into the model was to assist in addressing elements of SB 375, and to pave the way for a possible transition to a tour-based modeling approach in the future. This updated model is a traditional four-step trip-based approach, and as such includes models for Trip Generation, Trip Distribution, Mode Choice, and Trip Assignment. Specific differences compared with traditional approaches include a population synthesis to drive the trip generation socioeconomic variables, calculation of the 4D variables (Density, Diversity, Design, and Destinations) using GIS techniques to support inputs to various model stages, the use of person-based trip rates, destination choice model for the trip distribution, and a mode choice component designed and estimated entirely from the survey.

The new model represents a significant improvement in functionality to the previous AMBAG RTDM. The updated AMBAG RTDM has implemented most of the short-term and medium-term model improvement recommendations from the 2011 Travel Model Improvement Program (TMIP) peer review. A peer review of the updated RTDM took place in August of 2013. The model was used to develop AMBAG’s 2040 Metropolitan Transportation Plan (MTP) and Sustainable Communities Strategy (SCS). For more information, please review the AMBAG 2018 RTDM technical documentation

Central Coast Supra-regional Activity-Based Model (ABM) Framework Project
The Association of Monterey Bay Area Governments (AMBAG), San Luis Obispo Council of Governments (SLOCOG), the Santa Barbara County Association of Governments (SBCAG), and the California Department of Transportation (Caltrans) partnered to develop a cost-effective and advanced Activity-Based Model (ABM) framework for California's Central Coast region. Although the Central Coast is composed of three, separate metropolitan planning organizations (MPO) and three, distinct regions covering five counties, the geographical, three-MPO supra-region as a whole exhibits many similarities with respect to land use patterns, growth, and socio-demographic and travel behavior. A common, state-of-the-art, activity-based travel modeling framework will achieve more consistent, reliable travel predictions and modeling results and reduce the overall costs of maintenance and development associated with isolated model implementations. The Agency Partners will benefit from integration of enhancements envisioned by each agency partner and a common platform should expand the modeling knowledge base as well.
A team of professional consultants, Caliper Corporation Inc. and Fehr & Peers was selected and approved by AMBAG Board of Directors at their June 2017 meeting. An overarching goal of this project is to develop a framework and implement ABMs that are superior to the advanced trip based models currently in use at AMBAG, SLOCOG, and SBCAG. The new framework is intended to improve upon the policy sensitivity of the existing models through enhanced accuracy in the depiction and prediction of travel behavior. However, it may also improve upon the data that are used for modeling purposes by time of day and location. The ABM is a new generation travel demand model based on behavioral theory and simulates daily activity and travel patterns of individuals at a fine resolution, which is expected to meet California Senator Bill (SB) 375 and Governor’s Executive Order B-30-15 requirements

Contact Bhupendra Patel, Director of Modeling, at bpatel@ambag.org if you have questions regarding AMBAG's Regional Travel Demand Modeling activities.

Modeling Programs

The Monterey Bay Area Regional Bicycle Travel Demand Model project analyzes bike counts, route data, inventories of existing bike facilities, and a survey of travel behavior to improve planning