Can the Speed of a Vehicle Be Determined After a Crash? | Staver
Car Accidents

Can the Speed of a Vehicle Be Determined After a Crash?

If you were injured in a car crash and believe the other driver was speeding, we can hire an accident reconstruction expert to calculate the at-fault driver’s velocity at the time of the crash.

Our team of car accident attorneys at Staver Accident Injury Lawyers, P.C., are well-versed in the ways to establish speed during a claim. We also have worked with many accident reconstruction specialists in proving speed-related negligent in previous cases. We know who to call for help in calculating the at-fault driver’s velocity.

If you or a loved one suffered harm in a car accident in Illinois, contact one of our car accident injury lawyers today at (312) 236-2900 or contact us online for a free consultation.

Why You Need to Establish the Speed of Vehicle in a Crash

Vehicle speed is often essential in establishing fault and damages after a crash. If you can show that the driver who hit you was speeding above the speed limit or what was appropriate for the conditions, then you can use speed as evidence of the driver’s negligence.

Further, you can use an estimate of the vehicle’s speed to prove that your damages were actually caused by that accident. For example, if you can demonstrate that another vehicle was going too fast when it rear-ended your car, you’ll have evidence showing your caved in backend and whiplash were from the rear-end crash and not a previous incident.

But to use speed to establish negligence and causation during an insurance claim or personal injury lawsuit, you need an accurate and reliable estimate of the other vehicle’s speed. You cannot rely on the other driver to be honest about how fast they were going, which is why we recommend calling a Chicago car crash lawyer as soon as possible.

Accident Reconstruction Experts Can Calculate Vehicle Speed

When a large damages award is on the line, both parties to a suit might hire expert consultants to provide the jury with facts and professional opinions about the accident. These experts gather data from the accident scene and then use scientific theories and equations to make inferences about factors such as a car’s speed, when a driver applied the brakes, or whether a driver swerved to avoid the collision.

There are several possible equations an accident reconstructionist can use to calculate a vehicle’s velocity at the time of the collision. Which equation an accident reconstructionist uses depends on the data they have and the type of crash that occurred. For example, the equation will differ if you were stopped when the other vehicle hit you versus if you were also in motion when the crash occurred.

Infographics showing 6 tiles of ways to determine prior speed

To determine a vehicle’s speed, an expert will measure the length of skid marks. Skid marks occur when a vehicle’s tires lock and are dragged across the pavement. Each tire’s skid mark will be measured, then the average skid distance is determined by adding the lengths together and dividing by four.

The accident reconstructionist will determine the amount of damage the vehicle received upon impact.
Auto manufacturers and regulatory agencies keep data about the speeds at which bumpers, crumple zones, and side panels will fail. This automatically narrows down whether a collision occurred below or above a certain speed.

Drag factor, or the coefficient of friction, also is a critical part of the speed equation. Different road materials, such as asphalt, cement, or gravel, each have a different drag factor. The presence of ice also impacts the drag factor.

Another factor is braking efficiency. Vehicles with rear-wheel drive, front-wheel drive, or four- or all-wheel-drive may have different braking efficiencies. Also, the braking efficiency of a vehicle depends on how many tires locked and caused skid marks prior to the accident.

The accident reconstructionist will consider the grade of a road if the vehicle was moving up or down a hill at the time of the accident. They may also consider the superelevation, or the bank of the road, or the radius of a curve in the road.

An additional factor that may be necessary is the weight of each vehicle, which the accident reconstruction specialist can obtain from the manufacturer’s information.

All of these factors are translated into data that can be entered into the equation to calculate the vehicle’s rate of speed. Given the complexity of this equation, it is essential you work with a highly educated and experienced accident reconstruction expert, and preferably one who has participated in an insurance claim or testified in court before.

Learn More About Car Accident Reconstruction in Chicago >>

Using Evidence From the Accident Scene to Determine Speed

Manufacturers carefully design and test their vehicles as well as specific parts of their vehicles. They have information on how much force a certain part of the vehicle can withstand before cracking or crumpling.

During a car accident claim, we will gather this data for your vehicle. It can quickly help us and our accident reconstruction expert narrow down how fast the other driver must have been going to do the damage they did.

Say your vehicle has a bumper that can withstand impacts of up to 10 mph without breaking. After the crash, though, your bumper is completely destroyed. But the crumple zone, which will fail at impacts greater than 30 mph, is intact. (The crumple zone, also known as the crush zone, is a structural safety feature. It is an area of the car that is designed to crumple and absorb energy from the crash to prevent that energy from reaching and harming the occupants.) From this information, we can infer that the impact speed was somewhere between 10 and 30mph.

Imagine that there are 150-ft skid marks leading up to the point of impact. An expert would investigate the road surface conditions at the time of the accident, research the car’s braking performance, and look into what kind of tires were on the car on the day of the accident.

Based on this information, an expert can calculate the approximate speed at which the vehicle must have been traveling to still be moving between 10 and 30 mph after breaking for 150 feet. Some sports cars can decelerate from 60 mph in 100 feet. Large commercial trucks, on the other hand, would take double or triple this distance to decelerate.

Jared Staver Law Firm is incredible. I felt comfortable and secure with them throughout the whole settlement. They were able to get me a nice compensation.”

Learn About How Medical Evidence Can Be Used in Car Accident Case >>

Witnesses and Accident Footage Can Help Establish Speed

Accident reconstruction experts are very expensive. We only hire them for complex and high stakes cases. For the average fender bender, we usually rely on witness statements, accident footage, and evidence from the scene to determine speed.

Although witnesses are notoriously unreliable, we will ask people who were at the scene how many seconds it took for a car to cross an intersection and use that number to calculate that car’s speed. A more reliable method is to gather footage from traffic cameras or the security cameras of a local business that may have captured the accident.

Witnesses also may have heard a vehicle apply its brakes and skid before crashing into the other car. We will ask how many seconds occurred between the noise of the brakes starting and the sound of impact.

Gathering Vehicles’ Electronic Data

A majority of modern vehicles have so-called “black boxes” that record vehicle and event data, such as GPS location, speed, deceleration (braking), seatbelt use, airbag enabled/disabled state, as well as impact-related factors, like the time between impact and airbag deployment. This electronic data recorder can tell us how fast the other vehicle was moving in the minutes before the crash, when the driver applied the brakes, and how fast the vehicle was moving at the time of impact.

By 2020, almost all auto manufacturers include an EDR of some kind in their vehicles, though it is not technically required by the National Highway Traffic Safety Administration. The NHTSA originally sought to have all cars and trucks include an EDR, but they rolled back the regulation because almost all manufacturers voluntarily equip their vehicles with this equipment.

Each manufacturer has their own hardware and software for EDRs, some of which can be accessed by a driver or service provider and others that are only accessible by the manufacturer. We may not have direct access to the other vehicle’s black box. This is why we might recommend filing a personal injury lawsuit as soon as possible. During the discovery phase of litigation, we can demand that we receive a copy of all of the vehicle’s electronic data.

Call a Chicago Car Accident Lawyer to Determine the Speed of a Vehicle After a Crash

Following a car crash, you probably have a lot of questions, including how fast was the other car going, and can the speed of a vehicle be determined after a crash? Yes, we can usually determine how fast the other car was going based on physical evidence of the crash, electronic data, and by hiring an accident reconstruction expert.

If you have any other unanswered questions, give the lawyers from Staver Accident Injury Lawyers, P.C. a call at (312) 236-2900 for a free consultation.

“From the first day we contacted Staver Accident Injury Lawyers, P.C. to the close of my case every single person we spoke to was knowledgeable and patient. Staver Law Group treated us if we were part of their family. I’m so thankful for the financial compensation and great doctor care I received through this process. I will recommend Staver Accident Injury Lawyers, P.C. to anyone that has been in an accident.”

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