Transportation Control Measures (TCMs)
TCMs are strategies that reduce transportation-related air pollution by improving traffic flow and reducing vehicle use. They can be adopted as SIP control measures or contingency measures. TCMs may be adopted as control strategies to meet attainment demonstration and reasonable further progress requirements, and implementation of a TCM program is required under certain circumstances by the federal Clean Air Act (CAA) for a nonattainment area classified as serious or above. The federal CAA, §108(f)(1)(A) lists examples of potential TCMs, including:
- programs to improve public transit;
- trip-reduction ordinances; and
- traffic flow improvement programs.
When TCMs included in the Texas SIP are approved by the United States Environmental Protection Agency (EPA), transportation conformity regulations require that the metropolitan planning organization in an affected area shows timely implementation by incorporating the TCMs into the area’s Metropolitan Transportation Plan and Transportation Improvement Program with sufficient, dedicated funding (40 Code of Federal Regulations (CFR)§93.113).
- State TCM Rule, 30 Texas Administrative Code (TAC) §114.270
- EPA’s Transportation-related Documents Webpage
- FHWA’s TCM Webpage
- Timely Implementation of TCMs Federal Rule, 40 CFR §93.113
State SIP and Rule Revisions
The state TCM rule, 30 TAC §114.270, is the enforcement mechanism for TCMs in Texas, and it describes the process of substituting one SIP-approved TCM for another. The TCM rule was originally adopted in 1993, with revisions adopted in 1994, 1997, 2000, and 2007. The most recent revision was approved by the EPA effective April 1, 2014.
Latest state rule revision:
2007 EPA approval effective April 1, 2014 (79 FR 5287)
- Revisions to 30 TAC Chapter 114, Control of Air Pollution from Motor Vehicles (Rule Project No. 2006-050-114-EN)
Previous state SIP and rule revisions:
2000 EPA approval effective January 6, 2003 (67 FR 72379)
- Revisions to 30 TAC 114, Control of Air Pollution from Motor Vehicles (Rule Project No. 1999-068-114-AI)
- Transportation Control Measures SIP for Texas Nonattainment and Maintenance Areas (SIP Project No. 1999-068-114-AI)
- Revisions to 30 TAC 114, Control of Air Pollution from Motor Vehicles (Rule Project No. 97163-114-AI)
TCMs included in the SIP
Dallas-Fort Worth (DFW) Eight-Hour Ozone Nonattainment Area
TCMs were included in the revoked one-hour ozone standard SIP revision adopted April 19, 2000 for the DFW nonattainment area (SIP Project No. 1999-055-SIP-AI). A number of TCMs adopted in that SIP revision were formally substituted in a January 14, 2004 TCM substitution. The DFW attainment date under the one-hour standard was November 15, 2007.
TCMs were included in the 1997 eight-hour ozone standard SIP revision for the DFW moderate nonattainment area adopted May 23, 2007 (SIP Project No. 2006-013-SIP-NR). The DFW moderate area attainment date under the 1997 eight-hour ozone standard was June 15, 2010.
Houston-Galveston-Brazoria (HGB) Eight-Hour Ozone Nonattainment Area
TCMs were included in the revoked one-hour ozone standard SIP revisions adopted December 6, 2000 (SIP Project No. 2000-011-SIP-AI) and 1996 (SIP Project No. 1996-109-SIP-AI) for the HGB nonattainment area. A number of TCMs adopted in those SIP revisions were formally substituted in an April 15, 2006 TCM substitution. The HGB attainment date under the one-hour ozone standard was November 15, 2007.
TCMs were included in the 1997 eight-hour ozone standard SIP revision for the HGB nonattainment area adopted March 10, 2010 (SIP Project No. 2009-017-SIP-NR). The HGB severe area attainment date under the 1997 eight-hour ozone standard is June15, 2019.
Air Quality Division, TCEQ
For information concerning transportation conformity in Texas, please visit TCEQ’s Transportation Conformity webpage.