Crash Types


Crashes at intersections can involve an on-coming vehicle versus a left-turning vehicle, cross traffic and, on rare occasions, two vehicles turning in the same direction where one strays out of their lane.

Single Vehicle Accident (SVA)

Single vehicle collisions often focus on why the vehicle left the roadway. Was it excessive speed, was the driver distracted, did they fall asleep, or was there a mechanical or tire failure that caused the loss of control? All of these are possibilities. The scene evidence and vehicle can often be enough to answer these questions.

Pedestrians and Bicycles

Pedestrian and bicycle accidents often result in severe injuries and involve what may seem like minor details. GPS bike computers, fitness apps on smart phones, and scene/vehicle evidence can often tell us all kinds of information: How fast was the pedestrian traveling? For how long and how far were they visible to the driver? Did they cross in the crosswalk? How fast was the vehicle going?


Motorcycle and scooter accidents present unique challenges that require specific methods to calculate speed and other collision details. The ability of the rider has a much larger affect on the dynamics of a two-wheeled vehicle, which often results in a loss of control. Braking, cornering, speed, visibility, and avoidability are common variables that can be solved to deduce a cause.

Low Velocity Impact (LVI)

A low velocity impact is typically one with an impact speed below about 20 km/h (but there is no set definition). In these collisions the main question is often, how severe was the collision? That can be addressed by examining the damage, or by the event data recorder, or occasionally by other methods. Other questions can be which vehicle was moving or who changed lanes into whom?

Commercial Vehicles

Heavy trucks, city buses and highway coaches present unique issues. They are equipped with complex air brakes, engine braking and other systems that can affect vehicle dynamics. These vehicles often have event data recorders built into the engine control computer and may have other on-board recorders. We have analyzed many such cases to determine speed, stopping ability, roll over from weight shift, etc.