DALLAS --- In hopes of preventing more wrong-way crashes on the Dallas North Tollway, officials are having new reflective buttons installed on lanes at each of the tollway's 47 exits.

The reflective buttons will be laid out in the shape of arrows, the Dallas Morning News reported. Headlights from a vehicle traveling the wrong way on an exit ramp will make the arrows pointing at the driver glow red.

North Texas Tollway Authority officials have also installed 25 new warning signs. That brings the total number of "Wrong Way" or "Do Not Enter" signs to 215.

Officials hope these measures will help reverse a trend. Thus far in 2009, there have been five wrong-way crashes on the tollway, killing four people and injuring several others.

Between 2003 and 2008, three people died in 28 wrong-way crashes, according to the Texas Department of Public Safety. At least 18 of those involved alcohol or drugs.

This year, alcohol has been a factor in three of the five wrong-way crashes.

Other ideas include using sensors already embedded in some NTTA lanes to measure traffic and to count the number of axles on a vehicle. The sensors could be strategically placed to detect the direction in which a vehicle is moving, the Dallas Morning News reported.

"That would signal the command center, where we could then dispatch law enforcement officials more quickly," explained NTTA spokeswoman Sherita Coffelt. 

But it's not known whether the sensors would work effectively. Staff members will continue to study this option, said NTTA Executive Director Allen Clemson.

"It's a national and international problem," Clemson said of wrong-way crashes.