San Joaquin Valley
Travel Model Improvement Program

The Project

The primary modeling requirement of California’s Senate Bill 375 is to analyze greenhouse gas (GHG) emission savings from cars and light-duty trucks through implementation of smart growth strategies. In April 2010, the eight San Joaquin Valley Metropolitan Planning Organizations (MPO’s) applied for and were awarded funds by California’s Strategic Growth Council for valley-wide model improvements.

By using Big Data, our team and our highly qualified partners were able to quickly update the MPO’s models to be more sensitive to smart growth in order to meet the requirements of SB 375, as well as develop each of their Sustainable Communities Strategies.

Our Use of Big Data

GHG reduction analysis relies heavily on the ability to adequately model interregional trips and speeds. Our partner, Airsage, has created a way to extract moment-by-moment data from cell phones to calculate vehicle speeds and origin and destination trip data. Trip distribution travel patterns tend to be some of the least well understood areas of travel demand modeling, so the cell phone database represents an important new set of information that is otherwise unavailable for model developers and model users. We were able to manipulate the data to provide a sample size for county-to-county origin destination flows that is 100 times larger than collecting data with traditional methods.

We also gathered traffic speed data from GPS-equipped vehicles, which allowed us to study all road activity at one time every five minutes versus gathering data over a one-month period.  We provided demographics and other commute data by using Census and American Community Survey data.

Results

By developing ways to more effectively use these data sources, we were able to provide better estimates and forecasts, gauge variability and reliability much more efficiently, gain better information on vehicle speeds and more accurately monitor congestion.

Our work helped the MPOs successfully meet their tight funding deadlines within budget and helped provide significant modeling improvements, including:

Z

A new three-county activity-based model and O/D travel survey for San Joaquin, Stanislaus and Merced Counties

Z

Updated interregional and truck trip models for the Valley

Z

Model sensitivities to 4D land use, travel speed, interregional travel, and Best Management Practices as described in SB 375

Z

A quick-response tool that evaluates the effectiveness of Transportation Demand Management (TDM) measures and helps report compliance with the Valley air districts’ employer trip reduction rule.

Z

Static and dynamic model validation and air quality conformity checking