The subject of impact speeds is often one of the most important issues to investigators of pedestrian collisions, particularly if there appears to be a violation of the law. Estimating vehicle speeds, is also crucial in civil cases, as it relates to negligence and liability. The various available techniques in descending order of accuracy, (although this can certainly be subject to interpretation) are:

1. Skid Marks

2. Pedestrian Throw Distance

3. Vehicle Damage

4. Pedestrian Injury

5. Witness/Driver Statements.

In many instances, an accident investigation is not requested for months or years after the incident. Crash investigators have had to reconstruct MVAs where

1. no verifiable skid mark information exists,

2. the pedestrian throw distance is at best a highly subjective calculation and

3. there are vastly different speed estimates from the drivers of the involved singly-occupied accident vehicles.

These factors can make an accident investigation interesting, but not unsolvable for the seasoned reconstructionist. Investigators can resort to calculating impact speeds by vehicle damage – almost always available via repair records and or photographs. Below is a graphic representing vehicle damage relative to impact speed.

From Vehicle Damage (if you cannot view the below image, simply click once in the image box)

BNI Operatives: Street Smart; Net Savvy

As Always, stay safe,

Lina

Filed under: crash investigation, crash investigations, impact, impact speed, pedestrian, skid marks, speed, throw distance, velocity, witness, witnesses