transportation director has approved the first of a handful of requests to reduce
speed limits in urban areas for large trucks and other vehicles as a way to
fight air pollution. Currently, all vehicles are allowed to drive 70 mph.
Gerald Nicely, commissioner of the Tennessee Department of
Transportation, announced the authorization for posting 55-mph speed limit
signs for large trucks in Hamilton County at a press conference Feb. 8 in
Chattanooga. All other vehicles would have new limits of 65 mph.
About 57 miles of interstate will be affected by the speed
limit changes. A section of U.S. 27 that runs about 17 miles will also have
lower speeds posted.
“After studying the issue we believe that lowering the speed
limit for large trucks will make a difference in air quality for Hamilton
County,” Nicely said. “A study conducted by the Federal Highway Administration
shows that reducing truck speed limits by 10 mph can reduce the nitrogen oxide
emission factor by approximately 18 percent or more per truck. If we get
reductions anywhere close to that level in Hamilton County it will be worth
Truckers in Hamilton County won’t see the new limit posted
until early summer, Nicely said. The speed limit for automobiles will also be
reduced at that time.
“The reason for reducing the speed of cars as well as trucks
is to lessen the difference between the rates at which the two types of
vehicles will be traveling.”
Mayor Bob Corker and Hamilton County Mayor Claude Ramsey requested the change
in truck speeds.
County is likely next in line for the lower limits. Similar requests from Knox
and Davidson counties also await action.
Officials in the state’s largest cities hope the slower
traffic will help their areas meet new federal air-quality standards for ozone
of Tennessee’s largest metropolitan areas failed last year to meet the new air
standards. Failure to develop plans to clean up the air by 2007 could result in
an end to industrial expansion and large cuts in federal highway funding for
Shelby County Mayor A.C. Wharton requested the lower limit
in a letter sent to Nicely last summer. The Tennessee Air Pollution Control
Board and Metropolitan Planning Organization backed the change.
The city of Chattanooga and Hamilton County have also
requested TDOT to authorize confining trucks to the right lanes.
spokeswoman Kim Keelor said the department was continuing to consider the
may be announcing something about that later this year,” she said.
speed limit and lane changes do not require state legislative approval.
– By Keith Goble, state legislative editor