Complete Mobile Source Modeling Application

BREEZE ROADS is a complete air dispersion modeling suite that includes CALINE4, CAL3QHC, and CAL3QHCR models. These air dispersion models are used within the software program to predict air quality impacts of carbon monoxide (CO), nitrogen dioxide (NO2), particulate matter (PM), and other inert pollutant concentrations from moving and idling motor vehicles at or alongside roadways and roadway intersections. BREEZE ROADS is used in conjunction with emissions data from MOBILE or other emissions models to demonstrate compliance with National Ambient Air Quality Standards (NAAQS), Federal Conformity Rules, the UK's National Air Quality Strategy, and modeling for highway site and design selection.


  • Estimate total air pollution concentrations from both moving and idling vehicles
  • Estimate queue lengths at intersections and the contribution of emissions from idling vehicles
  • Incorporate saturation flow rate, signal type, and arrival type data for intersection assessments
  • Calculate pollutant concentrations on at-grade roadways, depressed roadways, raised roadways, bridges, intersections, street canyon and bluffs, and parking structures
  • Includes the CALINE4, CAL3QHC and CAL3QHCR line source dispersion models and a traffic algorithm for estimating vehicular queue lengths at signalized intersections

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CALINE Series of Models

Most mobile source dispersion models predict air pollution concentrations near roadways resulting from motor vehicles traveling under free-flow conditions. BREEZE ROADS is an enhanced version of the CALINE4, CAL3QHC, and CAL3QHCR series of models that incorporates methods for estimating queue lengths and the contribution from idling vehicles. Learn more



Using BREEZE ROADS, users can tailor their analyses for a wide variety of scenarios by picking and choosing from the many advanced features this product has to offer. BREEZE ROADS gives users the ability to estimate queue lengths and emissions contributions from idling and moving vehicles on various types of roadways. A two-tiered approach is also employed in CAL3QHCR that allows for emissions, traffic volume, and signalization to be varied by day of the week. Learn more



BREEZE ROADS calculates concentrations from historical hourly or user-specified meteorological data. The user-friendly interface makes entering or loading your meteorological data easier than ever. Also, the CALINE models incorporated into BREEZE ROADS enable users to model a single hour of user-defined meteorological data, or historic, hourly meteorological data. With this flexible, streamlined approach, productivity skyrockets! Learn more


Sources and Receptors

Whether you're entering links or receptors, you enter them only one time. BREEZE ROADS gives users the ability to enter data by copying and pasting from an external spreadsheet to the data table within the software. This product also features CAD-like drawing tools enabling users to edit, move, and delete sources and receptors seamlessly. Additional productivity features for entering sources and receptors include the onsite receptor removal option, integrated unit conversion, unlimited... Learn more


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