By May, nearly 1,000 miles of highway in North Texas will see speed limits drop by 5 mph.

The Texas Department of Transportation last week approved the lower speed limits as part of an effort to help improve the area's air quality. Areas with 70- or 65-mph limits will see them lowered by 5 mph. Speed limits of 60 mph or lower will not change.
Local leaders came up with the idea last year when looking for ways to address the area's problem with ozone pollution. The state environmental agency approved a comprehensive plan last year, including the speed limit reduction. Federal officials gave their approval to the plan this month. The state DOT's approval was the last hurdle in making it happen.
The following counties will be affected: Dallas, Tarrant, Collin, Denton, Rockwall, Ellis, Kaufman, Johnson and Parker.
In Houston, which has surpassed Los Angeles as the city with the worst pollution in the country, officials have proposed a maximum 55-mph speed limit.