What's being done to prevent wrong-way drivers in the future?

Another wrong-way driver slammed into a car traveling in the opposite direction. It was a terrible crash and both drivers died.

The collision shut down the Loop 101 at Interstate 17 for more than five hours on Tuesday morning. The freeway has re-opened, but we're learning more details about the crash and about what's being done to prevent wrong-way drivers in the future.

The issue seems really simple, how do you prevent people from driving down the wrong ramp onto the freeway? But that question doesn't have any simple answers.

The horrific crash raised a familiar question about stopping the impossible.

"What can you do in that situation? I can't think of anything myself," said Michael Thomson.

Under the influence, driving a car and heading down the wrong way onto the freeway and almost certain disaster awaits.

"The battle against the impaired driver is a really challenging one," Doug Nintzel of the Arizona Department of Transportation.

ADOT says it continues to work on technology that will use the sensors in the road to alert authorities about wrong-way drivers.

"It's going to help with the response of law enforcement. Hopefully, officers can get there that much sooner and then also being able to warn other drivers on the freeway as quickly as possible," said Nintzel.

"Maybe, the spikes or something like that. Or something that might prevent.. some kind of a device to keep people from going that way," said Scott Sheets.

It's a common question that ADOT says it gets, but the research says it doesn't work.

"They are not meant for and don't hold up when you put them on an off-ramp on the freeway. The spikes tend to break off, they become that type of a maintenance issue, they can damage other vehicles," explained Nintzel.

Thomson says staying alert on the road might make the difference.

"I kinda of scan the road, I look for people with their headlights off and I do look for wrong-way drivers especially on the freeways here."

"If you're out there, at those hours, in the middle of the night along the freeway, it's now time to think about using the center to the right lanes because wrong-way drivers tend to use the left lane as you're driving along the freeway," said Nintzel.

And Nintzel says that's because drivers think they're driving on the right side of the road, so it makes sense.

Since 2014, you have seen a lot of those "WRONG WAY" and "DO NOT ENTER" signs. They're helping, but there's only so much you can do.