Trip-Based Travel Model: 4k

Last Updated: 
Jun 12, 2015

The trip-based model is a system of mathematical and statistical processes that estimates daily travel patterns within the Puget Sound region. 4k is the official travel forecasting model at PSRC.

How Does the Trip-Based Travel Model Work?

For every household in the region, the model estimates how many trips are made each day, where they go, what time of day they travel, which modes they use, and which routes they follow. The relationships that are estimated for the 2010 base year are combined with future population, employment, and transportation infrastructure growth assumptions to produce future travel forecasts. The future travel forecasts are then analyzed to inform regional transportation studies and plans. The model uses Inro’s Emme software and is built entirely in the Emme macro language.

Download Files

4k Model Source Code

Instructions for Version 4.0.3

2010 Model Inputs

2040 Model Inputs

Version History—Version 4.0.3 Changes (Released: April 2015)

Version 4.0.3 Documentation

Frequently Asked Questions

How Does the 4K Model Fit in With Other PSRC Models?

The 4k travel model is one model in the suite of tools at PSRC to analyze future travel behavior. The 4k model is a traditional Trip Based Model which was used for the most recent Transportation 2040 Plan update in 2014. The 4k model relies upon population and employment forecasts from the land use model at PSRC. The model is used to generate forecasts to provide travel measures for use in regional analysis.

What’s New With This Model?

The 4k model includes a series of model improvements intended to advance the capabilities of the model for transportation analysis. These improvements include expansion of the zone system, roadway networks from a geodatabase and transit networks from the region’s GTFS inputs. The model was built from the previous 1C model that was used by PSRC for the 2010 Transportation 2040 Plan Update.

This model version also includes updates to trip generation, mode choice and trip distribution from the 2006 Puget Sound Household Travel Survey as well as the 2010 Census. The base year model was updated to 2010 and currently generates forecasts for 2010, 2025 and 2040.

Reference Files