Evaluation of the CAL3QHC and CALINE4 Roadway Intersection Models using New York City Database and MOBILE5 Emission Estimates (pp. 125-142)
Authors: (Irfan Patel, Ashok Kumar, Department of Civil Engineering, University of Toledo, Toledo, Ohio, USA)
Abstract: In most developed cities, traffic is the most important source of air pollution and
pollution from major roads is also important in suburban and rural areas. Vehicular
dispersion models are therefore essential computational tools in modern municipal and
urban planning. Due to their simplicity and direct applicability for estimates on a local
scale, various versions of the Gaussian line source model have been used for dispersion
evaluations from a road. The CAL3QHC (Version 2.0) model has been selected as the
recommended CO intersection model in the Guideline on Air Quality Models (Revised)
for intersection modeling. CAL3QHC enhances the CALINE3 model by calculating
pollutant concentration emitting from both idling and free flow vehicles.
Two popular models (CAL3QHC and CALINE4) have been evaluated using a New
York City database developed by the U.S. Environmental Protection Agency in 1992.
The MOBILE 5 model has been used in place of the MOBILE 4.0 model for calculating
the emissions from the vehicles.
This study uses several performance measures such as model bias, fractional bias,
fractional variance, normalized means square error, index of agreement, coefficient of
correlation, geometric mean bias, geometric mean variance and factor of two to evaluate
the two models. Detailed and in-depth evaluation of the models gave a better picture of