FORT WORTH — Speed limits on Interstates 20 and 30 could creep up, just a little, within six months.Texas Department of Transportation officials are looking to increase limits on those highways by 5 mph in Tarrant County and up to 10 mph in Dallas County after recent studies revealed that greater speed does not have as much impact on emissions as had been suggested.In Tarrant County, I-20 from Loop 820 West in Fort Worth to Texas 360 in Arlington, and a stretch of I-30 in west Fort Worth could go from 60 to 65 mph, pending a study by the North Central Texas Council of Governments.“The 5 mile per hour is hypothetical based on the previous speed reduction. In effect, a 5 mile-per -hour increase would return the speeds to their previous limits; however, the exact increase could be lower or higher pending the results of the study,” department spokesman David Glessner said.Speed limits were lowered in 2001 to offset high emissions in nonattainment areas such as Fort Worth and Houston. Fort Worth got a 5-mph reduction, and Houston was stuck with a 55-mph maximum on highways.Those reductions were based on studies that found that nitrogen oxides increased with high speed. Growing congestion on the highways along with higher emissions from trucks with diesel engines were thought to cause emission problems, said Chris Klaus, a senior program manager for the council of governments.But the Legislature wasn’t too pleased about the drastic limitations in Houston, Klaus said.“I think the Legislature got wind of this and they chimed in and said: ‘Uh, uh. Nobody is going to start messing around with speed for environmental purposes,’” Klaus said.He said Tarrant County’s small 5-mph reductions weren’t what set lawmakers off, but where would it end? he asked. When the speed limit was reduced to 45 mph on highways?As a result, in 2011 state lawmakers said the Texas Transportation Commission could increase speeds up to 75 mph if it’s determined reasonable and safe. The Environmental Protection Agency also produced new emission models suggesting that vehicles now run more efficiently. “A lot of what we’ve discovered over the past 13 years is [that] cars have become cleaner and emissions are better,” Klaus said.This caused the Transportation Department to rethink the current speed limits, and Klaus is looking for ways to offset even the slightest emission increases pending reinstatement of the pre-2001 speed limits, such as reducing traffic signals along frontage roads and finding ways to allow more efficient traffic flow in highway construction areas.Klaus said the study could be completed by the spring. After the study, the council of governments will submit information to the EPA and the Texas Commission on Environmental Quality.
Monica S. Nagy, 817-390-7792 Twitter:@MonicaNagyFWST