NASHVILLE (AP) — A national transportation research group's study says deterioration, congestion and lack of safety features on Tennessee roads and bridges cost the state's drivers $6 billion annually.

The report by TRIP was released Tuesday, the day before a House floor vote on Gov. Bill Haslam's plan to raise the gas tax for road improvements.

The group says the $6 billion figure includes higher vehicle operating costs, traffic crashes and congestion-related delays.

The report says the average extra cost to each driver annually is $2,019 in Memphis, $1,667 in Nashville, $1,471 in Chattanooga and $1,376 in Knoxville.

Tennessee Infrastructure Alliance Chairman Bill Moore says the funding proposed by Haslam is necessary as congestion in cities rises.

The report says congestion in Nashville causes 45 hours of delay annually for the average driver.