4.11 Accident investigation

Front

What is the drag factor in accident investigation?

Back

The drag factor is a coefficient that represents the friction between the tires and the road surface, used to calculate stopping distances.

Front

How do you calculate the average speed from skid marks?

Back

Average speed can be calculated by determining the distance of the skid marks and factoring in the drag factor and brake efficiency.

Front

What is the significance of skid mark length in accident reconstruction?

Back

Skid mark length helps determine the speed of a vehicle at the time of braking, which is crucial for accident analysis.

Front

What does a brake efficiency of 90% indicate?

Back

It indicates that the brakes are functioning at 90% of their optimal performance, affecting the stopping distance.

Front

How do you determine the skid distance to use for speed calculation?

Back

The skid distance used is typically the average of the longest skid marks, as it provides a more accurate representation of the vehicle's speed.

Front

What is the middle ordinate in relation to yaw marks?

Back

The middle ordinate is the distance from the midpoint of a chord to the arc of a curve, used to calculate the radius of the curve.

Front

What is the formula to calculate the radius of a curve using the middle ordinate?

Back

Radius = (Chord Length^2) / (8 * Middle Ordinate) + Middle Ordinate.

Front

What is the purpose of an accident reconstructionist?

Back

An accident reconstructionist analyzes the evidence from an accident scene to determine how the accident occurred and the factors involved.

Front

What is the average speed if a vehicle leaves skid marks of 70ft, 72ft, and 71ft on a road with a drag factor of .78?

Back

The average speed is approximately 40 miles per hour.

Front

What does a skid mark of 55ft indicate about Ron's speed?

Back

It indicates that Ron was likely driving faster than the speed limit, as the average skid distance suggests a higher speed.