Texas Emissions Testing

Vehicles in Texas registered in some of the most densely populated areas are subject to annual emissions testing. These areas have been identified by the U.S. Environmental Protection Agency (EPA) as "non-attainment areas" with poor air quality. The EPA has mandated that Texas implement measures to reduce pollutants that contribute to poor air quality. In response, Texas emissions standards were set and an emissions testing program implemented for the designated areas.

Texas Counties where Vehicles Must Have an Emission Test

All gasoline powered vehicles, 2 to 24 years old, registered in Brazoria, Fort Bend, Galveston, Harris, Montgomery, Collin, Dallas, Denton, Ellis, Johnson, Kaufman, Parker, Rockwall, Tarrant, Travis, Williamson and El Paso counties, must have emissions testing. Three different emissions testing procedures are used. Vehicle model year and county of registration determine which test is performed. Diesel vehicles are exempt from Texas emissions testing.

Types of Texas Emissions Testing

Three different types of emissions testing are used and the three test types are:

• Two Speed Idle (TSI)
• On-Board Diagnostic (OBDII)
• Accelerated Simulation Mode (ASM)

In El Paso, Travis and Williamson counties, vehicles manufactured in 1995 or earlier receive the TSI test. Vehicles manufactured after 1995 receive the OBDII test. In the Dallas - Fort Worth, Houston/Galveston areas, for vehicles manufactured in 1995 or earlier, the ASM test is used and for models manufactured after 1995, the OBDII test is used. The TSI test utilizes an analyzer to test tailpipe emissions. The ASM, also a tailpipe test, uses a dynamometer to measure emissions under simulated driving conditions. The OBDII utilizes the on board computerized systems installed in vehicles manufactured beginning with 1996 models that monitor the proper functioning of emissions systems. Vehicles fail emissions testing when excessive hydrocarbons, carbon monoxide, or oxides of nitrogen are detected by tailpipe testing or when on board computerized systems detect malfunctions of emissions related components.

Texas Emissions Testing Locations

Privately owned, state certified, licensed state inspection stations exist throughout the cities and counties where emissions standards are in effect. Texas State inspection Stations must meet specific certification criteria established by the state. Individual inspectors employed by the stations must attend an eight-hour state inspector's course, pass a written examination, and pass a practical exam in order to work in a state inspection station. Costs for emissions testing vary by geographic location ranging from $14.25 in El Paso County to $39.75 in North Texas counties.

Sources:

1. "Texas Attainment Status by Region". Texas Commission on Environmental Quality. June 16, 2009 http://www.tceq.state.tx.us/implementation/air/sip/siptexas.html#naas.

2. "Motor Vehicle Emissions Testing in Texas". Texas Commission on Environmental Quality. June 16, 2009 http://www.tceq.state.tx.us/implementation/air/mobilesource/vim/overview.html.

3. "Electronic Code of Federal Regulations, Title 40: Protection of the Environment, Part 81 - Designation of Areas for Air Quality Planning Purposes, Subpart C - Section 107 Attainment Status Designations - Texas". GPO Access (National Archives and Records Administration). June 16, 2009 http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?c=ecfr&sid=8b69a9dd1eb8ee672854597a917e77a2&rgn=div8&view=text&node=40:17.0.1.1.1.3.1.45&idno=40.

4. "The OBDII Home Page". Auto-tap. http://www.obdii.com/background.html.