No Signs Other Driver Was Drunk in Byrd Crash

There were no obvious signs the 17-year-old driver who crashed into NY Jets legend Dennis Byrd was drunk or texting at the time of the fatal crash ... law enforcement tells TMZ Sports.

50-year-old Byrd was killed when a Ford Explorer slammed into his Hummer H2 at 11:16 AM in Oklahoma on Saturday.

Cops say the driver of the Ford was a 17-year-old boy -- who had a 12-year-old passenger. Both boys were hospitalized in stable condition.

Investigators believe the 17-year-old veered across his lane and into oncoming traffic -- colliding with Byrd's car ... and killing him.

So, why did the car veer in the first place?

Cops tell TMZ Sports there was nothing at the scene to lead police to believe the 17-year-old was drunk. However, blood was drawn and is being tested to see if there was anything in his system.

We asked if the driver could have been distracted by his phone at the time of the crash -- we were told, "The driver's phone was off when officers arrived."

Cops are still investigating.