Sunday, August 13, 2006

No speed limit signs on State Highway 121 toll road

State not being hasty about 121 toll speeds

August 13, 2006

Tony Hartzel
The Dallas Morning News
Copyright 2006

Something is missing along the new State Highway 121 toll road in Denton County: speed limit signs.

But motorists should think twice before heading out to the highway for a speed-induced adrenaline rush.

Even without speed limit signs, the highway has an enforceable 70 mph speed limit, said Andy Oberlander of the Texas Department of Transportation.

"And there is not an accident problem out there on Highway 121. The majority of people are driving at safe and prudent speeds," Mr. Oberlander said.

Under state law, 70 mph is the default maximum speed limit on state highways.
On residential streets without speed limit signs, it's 30 mph.

On Highway 121, the Dallas-area state transportation office decided not to post interim 70 mph signs.

The department is conducting a more thorough speed study.

That study, which measures the flow of traffic and requires radar guns, could soon validate a 70 mph speed limit or possibly something lower on 121.

"We would prefer to wait until we have the correct speed limit rather than a higher speed limit and have to change it in the future," Mr. Oberlander said.

Here's how a speed limit on a new highway is set: State crews wait until motorists get accustomed to the road, usually a few weeks.

Then they measure speeds of at least 125 vehicles in each direction at several spots.
The state tosses out the 15 percent of traffic that drives the fastest.

The remaining highest speed, known as the 85th percentile speed, is the basis for a recommended speed limit.

"Even without speed limit signs, the majority of the public does drive a safe and prudent speed. And that's how speed limits are set," Mr. Oberlander said.

Speed survey results must be approved either by the Texas Transportation Commission in Austin or by city councils and county commissioners courts along the highway route.

State officials expect speed limit signs to be installed within months.

• Kudos to the city of Dallas, which reopened westbound Walnut Hill Lane after closing it for most of the summer.

In late May, the city took the dramatic step of closing all westbound lanes between Rambler Road and Greenville Avenue.

Workers rebuilt all westbound lanes.

The goal was to reopen the road in time to handle traffic for nearby McShan Elementary School, which has its first day Monday.

• Dallas Area Rapid Transit bus riders should pick up new schedules.

The transit agency has tweaked its service in Dallas, Garland, Plano, Addison and Irving.

Schedules are available on buses and at transit centers, online at www.dart.org and online in Spanish at www.transporte dart.org.

Tony Hartzel can be reached at thartzel@dallasnews.com and at P.O. Box 655237, Dallas, Texas 75265.

© 2006 The Dallas Morning News Co www.dallasnews.com

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