One in 8 drivers is talking on a cellphone while navigating the shifting, narrow lanes of the DFW Connector project through Grapevine, a study by the Texas Transportation Institute has found.

That's more than twice the 5 percent observed on phones in a Dallas study over 10 years ago, according to Jason Crawford, a research engineer who co-authored the study. And it is twice the level observed in a 2009 regional study by the National Highway Traffic Safety Administration.

Those drivers are endangering themselves and other drivers and work crews, the study says.

Using cellphones while exceeding the 50-mph speed limit through the connector is a bad combination, Grapevine police Lt. Todd Dearing said.

"We need to get people to pay attention," he said.

Crawford speculates that the greater phone usage may be due to the project's proximity to Dallas/Fort Worth Airport. Drivers going to or from the airport may be using their phones to reconnect with people before or after a flight.

Whatever the reason, distracted drivers in a work zone are dangerous, said Selma Stockstill of NorthGate Constructors, the company overseeing the $1.02 billion project. She said NorthGate is doing everything it can to raise awareness about the issue.

For two days in March, observers stood on the Northwest Highway bridge over Texas 114 and the Mustang Drive bridge over Texas 121. They saw 73,252 vehicles and tallied how many drivers held cellphones to their ears or in the same hand as the steering wheel, Crawford said.

They noted whether the person was using a phone, was not using a phone or may have been using a phone; the maybes were later classified as not using a phone to ensure that the number of users was accurate.

The observers also noted other distracting habits such as eating, drinking, reading, texting, putting on makeup and wearing headphones.

In addition to the drivers holding a phone to their ear, Crawford said, others were likely talking hands-free, which can also be distracting.

Using data from a previous study on drivers using hands-free phones, he estimates that 20 percent of connector drivers were not fully paying attention to the road because of cellphones.

"The act of conversing does increase the risk," he said.

He cited a 2006 highway agency study that determined that the odds of a crash increase 30 percent when drivers are talking or listening on a cellphone and nearly triple when they are trying to dial a number.

The DFW Connector is scheduled to be completed in mid- to late 2014.