Lower speeds, rumble strips coming to I-35 work zones

In this Friday, Feb. 1, 2013 photo, traffic stacks up on a highway in Dallas. (AP Photo/LM Otero)
In this Friday, Feb. 1, 2013 photo, traffic stacks up on a highway in Dallas. (AP Photo/LM Otero)
In this Friday, Feb. 1, 2013 photo, traffic stacks up on a highway in Dallas. (AP Photo/LM Otero)

By Lowell Brown
Waco Tribune Herald via Associated Press

State transportation officials are rolling out several changes to Interstate 35 construction zones in Central Texas in response to a string of major wrecks and deaths.

Lower speeds, rumble strips and more warning signs will mark work zones along I-35 in the Waco area and parts of Hill, Bell and Falls counties.

Some new 60-mph speed limit signs are up in Hill County, but most of the new safety features will go live in the spring, Texas Department of Transportation spokeswoman Jodi Wheatley said.

The changes come after transportation, law enforcement and construction officials met in the fall to brainstorm solutions after a series of fatal crashes and other highway-closing wrecks between Temple and Abbott.

In two of the crashes, both in the Elm Mott area, a construction worker on foot was killed in wrecks involving 18-wheelers.

“The consistent factor that we’ve been able to identify is driver inattention,” Wheatley said. “That’s why we have auditory and visual things coming up that will get people’s attention.”

Some drivers have urged TxDOT for months to set lower speeds in work zones, where 65- and 70-mph limits are posted now, but the process required approval by the Texas Transportation Commission and extensive work by engineers to ensure lower speeds were justified, Wheatley said.

A state law says TxDOT can’t “unnecessarily” lower speed limits through a work zone, and defining what that means can be tricky, she said.

“What we don’t want to cause is the speed limit to go up and down and up and down, because speed changes are places with their own special danger,” Wheatley said. “When traffic is traveling the same speed is the safest situation we can create.”

Under TxDOT’s plan, workers will post 60-mph speed limit signs at the site of overnight lane closures and remove the signs when the lanes reopen the next day.

The lane closures typically occur from 7 p.m. to 7 a.m.

Also, a 60-mph speed limit will be posted 24 hours a day in some areas with concrete traffic barriers and narrow shoulders, but Wheatley did not yet have a list of locations.

The Texas Department of Public Safety has agreed to work with TxDOT to enforce the lower speed, she said.

Two other features will alert motorists as they approach a temporary lane closure.

Rubber rumble strips will extend across main lanes ahead of closures, and portable message signs will offer real-time information on traffic delays.

The rumble strips are 11 feet long and 13 inches wide but less than an inch tall, just enough to make some noise and deliver a slight bump, Wheatley said.

“It’s going to be a more elaborate setup for the nighttime lane closure, but we hope it will get the drivers’ attention,” she said. “If you’re more aware you are coming up on a nighttime lane closure, there’s less inclination that you’ll stop suddenly because you are surprised.”

Radar technology

The message signs will use radar technology to monitor vehicles’ speeds near a work zone and display warnings to approaching vehicles when traffic is slowed or stopped ahead.

The technology has been around a while, but it usually involves devices left stationary at a work zone, said Jerry Ullman, a senior research engineer with the Texas A&M Transportation Institute, which recommended the alert system.

“That (stationary setup) works well for certain applications, but in an environment like we have now on I-35, where lane closures are occurring in different locations on different nights, it makes more sense to have a system deployed in conjunction with the lane closure itself,” he said. “This is a very unique application, and the most innovative part is the … highly mobile part of the system.”

Giving drivers accurate information about work zone backups should result in fewer rear-end crashes, he said.

The construction is part of a state project to expand I-35 to at least three lanes in each direction from San Antonio to Hillsboro.

Most of the area not already expanded goes through TxDOT’s eight-county Waco district.

The state plans to raise the speed limit on I-35 to 75 mph through parts of Central Texas once construction is complete.