For Immediate Release
October 21, 2010

Caliper Completes Innovative Traffic Micro-simulation of an Entire Small City

NEWTON, MASSACHUSETTS (USA) - Caliper Corporation announced the recent completion of a very detailed simulation of the traffic in the entire city of Eureka, CA.  Using Caliper’s innovative TransModeler traffic simulation software, the simulation models the location of all vehicles every tenth of a second as cars travel from origins to destinations choosing routes that take traffic conditions and traffic signals into account.

Approximately, two years ago Caliper was selected by the Humboldt County Association of Governments (HCACOG) with funding from Caltrans to develop a micro-simulation model of the Greater Eureka Area (GEA) in TransModeler, and to collect data, to calibrate, and to validate the model.  The purpose of the project was to develop and deliver a model to HCACOG member governments under the technical supervision of Caltrans District 1 that could be used to study the traffic impacts of development and growth and to evaluate operational improvements.  Another goal was to help organize and unify the transportation planning and operations activities of the City, County, and the State in the region.  To that end, the micro-simulation model was integrated with the regional travel demand model and with Synchro, a signal timing program that is used locally.

This project presented Caliper with a unique opportunity to prove the feasibility of applying high fidelity micro-simulation to a wide area and presented a number of significant technical challenges for which the state of the practice has no precedent.  The model includes every one of the streets within the City’s 16 square mile area as well as extending beyond the City to include major gateways and through roads.  The geographic and geometric detail is accurate at the lane level and includes a detailed inventory of roads, detectors, traffic signals, bus routes, bus stops, and bicycle lanes, the attributes of which can be queried from TransModeler’s database.  Instead of assuming fixed turn proportions at intersections, dynamic traffic assignment is used to choose routes for each vehicle through a dense grid network with innumerable route choices for trips between the model’s 400+ traffic zones.

Dynamic 15 minute trip tables for the 3-hour AM and 4-hour PM peak travel periods were estimated and simulation-based dynamic equilibrium traffic assignment was used to produce the estimates of the travel times for the links on which the route choices were based.  The simulation model was calibrated against midblock and turning movement counts collected at more than 110 sites and was validated against travel times from GPS-equipped floating car runs on 30 routes.  Importantly, FHWA and Caltrans calibration criteria were satisfied for all major routes in the area.  Since the model was completed, Caltrans has been using the TransModeler simulation to evaluate the feasibility of roadway and access management strategies along US 101. 

TransModeler is a uniquely capable, GIS-based traffic simulator that offers the most accurate traffic models, ground-breaking GIS capabilities, and full 2-D and 3-D visualization.  TransModeler is integrated with Caliper’s TransCAD travel demand software which is used by a majority of regional planning agencies and states in the U.S. and works well in conjunction with other GIS and transportation software.

For more information, please visit ( or contact Daniel Morgan, Senior Transportation Engineer and TransModeler Product Manager (617-527-4700;

About Caliper

Caliper is a leading developer of mapping, redistricting, transportation, and GIS software, including Maptitude®, Maptitude for Redistricting, TransCAD®, and TransModeler®. Caliper software is used by more than 75,000 users in over 70 countries.