Lasers and broken speedometers are used by law enforcement officers when they reconstruct crashes. That's so they can determine what really happened.
Many people may think that a crash is investigated for a few days, but that's not so.
It takes a lot of training, hard work and skills from crash scene investigators.
Louisiana State Trooper Matt Harris took NBC 6 inside the crash investigation room at Troop G Headquarters in Bossier City.
That's where data from crash investigations is compiled. The data is used in studies to improve safety.
"I mean over the past decade, 62,000 lives have been saved over the evolution of vehicle safety devices," says Trooper Harris. "You know, your air bags, your child safety seats, your seat belts. And all that's from crash data."
Troopers use lasers to mark the positions of vehicles on the road and the transmit that data into their computers.
They can even tell how fast a vehicle was going by looking at a broken speedometer.
Troopers also go through extensive training at Northwestern State University; training that requires mastery in many areas.
"In that course you learn all the basics of crash investigation," says Trooper Harris. "You get all the formulas. You actually put the formulas to use. You recreate the intersections, crash scenes, so on and so forth."
When reconstructing a crash, investigators use a vehicle data recorder. It's basically a car's black box, and they say it's vital to their investigation."
The vehicle data recorder is found in most vehicles under a seat, and troopers get all kinds of information from it.
"They can tell whether or not the headlights were on, whether or not the blinkers were turned on, what rpm the motor was going, how fast the car was going," says Trooper Harris. "They can actually tell the reaction time of the driver."
Trooper Harris says the committment to hard work and public safety definitely have an impact on investigations.
He also told us that crash investigations normally last a month. That's because they want to make sure the investigation is thorough of course.
They want to avoid making mistakes by submitting date prematurely.