What is a collision reconstruction?

Collision reconstruction encompasses a review and investigation of all available roadway evidence, witness statements, and vehicles involved to recreate the events leading up to, and after the collision.

So what does it all really mean? It means an investigator, be it law enforcement or private, reviews the available written reports from the collision. This usually starts with the initial collision report and any supplemental reports that follow. The investigator reviews witness statements and information to compare and contrast what the witnesses remember. The vehicles are also subject to inspection to look for mechanical contributions, data download (ooh, a black box?), vehicle condition, and damage. The investigator analyzes this information to assist with understanding what happened. If available, the investigator uses available scene measurements and evidence to create a scaled diagram of the collision. Calculations can then be used to determine speeds of the vehicles involved. Finally, a completed report is created to recreate the events of the collision.

This changes for active law enforcement in that they investigate the collisions almost immediately after the collision occurred. Meaning they have access to roadway evidence. Law enforcement is also tasked with investigating criminal actions resulting in the collision, such as those collisions involving impaired drivers.

My car has a black box?


No, no it doesn’t. If your vehicle is equipped with airbags, then it has an airbag control module, or ACM. The primary purpose of the ACM is to monitor the vehicle for sudden changes in direction or roll. In addition to the sudden change in vehicle movement, the ACM may monitor seat position, passenger size, and seatbelt usage to control deployment of the airbags.

In this process, the ACM may record data about the vehicle, such as seatbelts, brakes, throttle, and speed. A copy of this data may be retrieved in what is known as “imaging” by a Crash Data Retrieval tool and used to assist with crash analysis.

But just in case, be careful how loud you sing in your car….just saying.

I’ve been in a collision. Should I get a police report?

Yes. Absolutely you should report the collision to the police. The police department will advise you how to proceed further. It is important to remember the police report serves as a third party documentation of the collision.

An officer may or may not respond to the scene to take the report depending on the local agency. In some jurisdictions, a minor collision might be taken by phone. However, you should obtain a police report number. Keep this number for your records. You will need it to provide to your insurance company and to order a copy of the report.

But perhaps more importantly, the information provided by all parties to the police department is recorded in an official document. While this does not guarantee a protection from those who might provide false information, it does make it a less likely.

What information am I required to provide when I’ve been in a collision? Or, what information should I expect to receive?

In Arizona, state law requires those involved in a collision to immediately stop at the scene of the collision, or as close as possible and immediately returning to the collision. After stopping, the law requires the driver of any vehicle involved in the collision to provide certain pieces of information.

As a driver in a collision, you are required to provide your full name, address, and the license plate number to the vehicle being driven. If requested, you must also provide your driver’s license to the other driver and, or the occupants in the other vehicle. Last, you must offer reasonable assistance to the injured person. The law requires that you may need to make arrangements to bring the injured person for medical treatment. Here it is important to call local law enforcement when a collision occurs. If there is a need for medical treatment, the responding officers will tend to the aid of the injured.

Last, and often overlooked fact, if you’ve been involved in a collision, all the above applies to you as the driver. Even if you were the one hit. Leaving the scene of a collision, even if not your fault, could still find you in criminal legal trouble for leaving the scene of a collision, or hit and run.

I just hit a parked car in the parking lot. What now?

You must stop at the collision, or reasonably close. No one would expect you to block a travel lane in the parking lot. But now you are obligated to locate the owner or driver of the parked car and provide them with your name, address, and owner of the vehicle you were driving. If you can’t find the owner, you must leave the same information in an obvious place on the car as if you had found the owner. Under the windshield wiper is a good spot.

It wasn’t a car I hit, just a small block wall. Do I have to report it? I mean, everyone knows the walls get hit every day.

Ooh, backing up and hit the wall? Ouch! When hitting a fixed object, like the parked car, you must stop and make reasonable attempts to notify the owner or responsible person (think manager, maintenance worker, or an employee) of the name, address, and owner of the vehicle you were driving. It is not acceptable to presume fixed objects are expected to be hit. With any luck, the owner may not be concerned with the object, but very appreciative of your honesty.

I’ve been in a collision. What should I do now?

Check that everyone is okay and call police. Have a phone with a camera? Great, use it to take pictures. Take four pictures of the collision scene, one each from a compass point. Next, take four pictures of each vehicle involved, again one from each compass point. Last, take close-up pictures of damage.

Above all, be SAFE when around a collision scene! Cars will likely still be driving past you and no picture is worth your life. Do not become so focused on “getting the shot” that you forget where you are and place yourself in danger.

Next, get the information of the other driver. You will want their name, address, and the license plate from their vehicle. Ask for a phone number. While not required, it could certainly be of benefit later. If you request it, the other driver is required to show you their driver’s license. Ask and then check to see the person in the driver’s license photo looks like the person presenting it. Remember, people change with time. So, it is reasonable to expect different hairstyles, changes in facial hair, weight, and even glasses.

The other driver wants to pay me cash and not “trouble” the police. Is that okay?

Whatever you do, don’t accept a cash offering in exchange for not calling police. It could certainly be innocent enough, and it is legal as long as the required information is exchanged. But experience shows it might be an attempt to prevent law enforcement involvement for other underlying causes. There could be warrants for arrest, a suspended license, no insurance, or impairment. The time of a collision is not the time to make those decisions that could have deeper and farther-reaching ramifications later. And under no circumstances should you become confrontational with the other person. Call police, especially if the other person becomes aggressive.

Okay, after the collision I’m starting to feel sore. Is that normal? Should I be concerned?

Yes, be concerned. Even a minor impact can have affects on your body. You should expect to be sore. This is normal. But, there could be other underlying causes for concerns. If you “just don’t feel right”, no matter the extent, you should be checked out by a medical professional. There is nothing wrong with being cautious.

Property can be replaced or repaired. People can be healed, but not replaced. If you have any doubt, see a medical professional.

Am I in the commercial vehicle regulations?

There are really three easy questions to answer that determine if you fall within the commercial vehicle regulations (Federal Motor Carrier Safety Regulations – FMCSR); First, are you using a vehicle to make money? Second, does the Gross Vehicle Weight Rating (GVWR) exceed 10,000 pounds? And finally, are you towing a trailer with a GVWR that exceeds 10,000 pounds? If you can answer yes to the first question and yes to either one or both of the next two, you are subject to the FMCSRs.

Okay, the subject bears a little more explanation. There are other factors involved, such as interstate and intrastate operations. Do you travel outside your home state? Then anything over 10,000 pounds places you firmly in the regulations. Operating solely within your home state, then the GVWR requirement can vary. In Arizona, the GVWR set for defining commercial motor vehicles is anything greater than 18,000 pounds.

Another consideration is hazardous materials. If you’re transporting hazardous materials, you may be in the regulations. Transporting 8 or more people including the driver for money? 15 people or more and not for money, you are a commercial vehicle as well.

What is the Gross Vehicle Weight Rating (GVWR)?

This is the weight rating provided by the manufacturer and usually found on the vehicle information sticker. The manufacturer has determined this is the total weight at which the vehicle can safely operate. This means the total weight of the truck, any cargo, equipment, and occupants. This is not the weight you declare to the motor vehicle department. While you may choose the weight to declare, the manufacturer has set the GVWR. Contact San Tan Recon and we can help clarify the regulations for you.

What is declared registered weight?

Declared Registered weight is the weight you report to the motor vehicle department when registering your vehicle or trailer to operate on the roadway within that state. In short, you are reporting the maximum amount of weight you plan to haul while driving on the roadway as a commercial vehicle. This is the combined weight of the truck or trailer, any cargo, equipment, and passengers.

Hauling landscape material? After a storm? Watch out! The extra weight of the water absorbed within the landscaped cargo adds a significant amount of weight. This could cause you to exceed the GVWR of the vehicle and the declared registered weight. Consider taking smaller, more frequent loads to the landfill.