A collision on northbound Loop 12 in Dallas has left only the far-right lane open early Thursday morning. 

The Texas Department of Transportation’s traffic tracker detected the collision near the Interstate 30 interchange at 5:07 a.m. Congestion is building on both highways, creating heavy morning commuter congestion. 

Dallas police did not responded to immediate requests for comment, and the number of vehicles involved remains unknown. 

Motorists should avoid Loop 12 in far west Dallas near Irving to prevent further congestion, and take alternate routes if possible. 

This is a developing story.