A Texas agency has received nearly 60,000 complaints about smoke-belching vehicles since a public reporting program began in 2007.
The Texas Commission on Environmental Quality encourages drivers to report vehicles they see emitting dirty smoke for more than 10 consecutive seconds. The state then sends a letter to the owner suggesting an inspection. Compliance is voluntary.

Houston leads all cities with about 15,300 complaints. Houston is the state's largest city with more than 2.1 million residents.

San Antonio was second with nearly 11,000 complaints. Austin came in third with about 9,400 complaints.

The North Central Texas Council of Governments, including Dallas-Fort Worth, has its own program and received about 30,000 complaints. Some of those complaints might also have been reported to the state.