KNOXVILLE, Tenn. (WVLT) -- A morning rush-hour crash Monday has Knoxville police re-evaluating it's SmartFIX40 accident response plan.
The wreck on 640westbound is the first major back-up since I-40 through downtown closed for the SmartFIX construction project.
Overall, police say the response went well. With the I-40 shutdown, 640's now the main traffic artery in Knoxville.
So when cars collide, police say a back-up is unavoidable.
Monday morning's crash halted traffic for more than four miles.
The accident happened near the Broadway exit on 640 westbound.
Knoxville police say a vehicle tried to merge on 640.
But the driver behind them was following too closely.
So when that merging vehicle slowed down, that set off a chain reaction of two rear-end collisions.
Police cleared the road in about five minutes, but traffic stood still for nearly forty minutes. That's how long police say it took wreckers to arrive.
Police will meet with TDOT to re-check the crash response plan, but police say it's up to you to prevent crashes like this.
Knoxville Police Spokesman Darrell DeBusk says, "Leave a little earlier, leave greater following distance between you and the person if front of you and pay attention to all the vehicles around you that goes no matter where you're traveling."
Police say this crash wouldn't have slowed traffic as much on I-40.
TDOT estimates downtown shutdown detours as many as 30,000 extra vehicles on 640 daily.
So, more cars will back-up sooner.
Monday there were no injuries, but a fatality or injury accident would've lengthened the delay.