Publication Detail

Modeling IVHS Emission Impacts, Volume II: Assessment of the CALINE4 Line Source Dispersion Model


Research Report

Suggested Citation:
Washington, Simon P., Randall L. Guensler, Daniel Sperling (1994) Modeling IVHS Emission Impacts, Volume II: Assessment of the CALINE4 Line Source Dispersion Model. Institute of Transportation Studies, University of California, Davis, Research Report UCD-ITS-RR-94-18

This report assesses the ability of the emission estimating algorithms contained in version 4 of the CALINE line source dispersion model developed by Caltrans (CALINE 4) to accurately predict carbon monoxide emissions from a fleet of motor vehicles. The CALINE 4 model contains algorithms that predict carbon monoxide emissions from discrete modal events of idle, cruise, acceleration, and deceleration. The vehicle test fleet used for the analysis are those vehicles contained in the Speed Correction Factor data base developed by both the United States Environmental Protection Agency and the California Air Resources Board (CARB).

A BASIC computer program was used to assess and compare the performance of the CALINE 4 algorithms to those incorporated in version 7F of the EMFAC model (EMFAC 7F) employed and developed by the CARB. The analyses demonstrate that the currently employed CALINE 4 algorithms are slightly superior to those contained in EMFAC 7F, and when modified to utilize individual emission rates (instead of fleet average emission rates), the CALINE 4 algorithms are far more robust at predicting fleet emission rates. The authors recommend that the CALINE 4 model be revised (during planned future revisions) to incorporate individual emission rates into its emission estimation procedures.

The modified CALINE 4 model algorithms are used to predict CO impacts of an applied intelligent vehicle and highway system concept; automatic vehicle identification applied to electronic tolling operations. The analyses show that electronic tolling in place of conventional toll plazas offers significant CO reductions under three different operating scenarios. The authors conclude that under certain applications, IVHS technologies can be beneficial to air quality.