Who Had The Green Light?

Who had the green light? A primer on the determination of the aspect of the traffic light in intersection accident investigations.

Who had the green light? This is usually the very first question that comes to mind when a motor vehicle collision occurs at a traffic light controlled intersection. When photographic evidence is not available, a method of investigation may be employed that may either identify or suggest which driver had the green light. This method inserts numerical data gleaned from police incident reports and verified statements into situation-specific mathematical formulae. The calculations are then reviewed in light of the circumstances surrounding the accident and a determination may be made. The degree of certainty of the green light determination is related directly to the availability and credibility of evidence and information.

In order to make a green light determination an involved driver must answer five situation specific questions. The answers to the questions following must, to the extent possible, be both accurate and true. Inaccurate, incomplete or false statements cannot be verified or be corroborated. Uncorroborated statements usually do not produce litigation-appropriate evidence.

1) Describe in detail the intersection, the placement of the traffic signals and the roads leading to it. Familiarity with the characteristics of roads approaching the intersection may suggest if grades or curves, or other obstructions prohibited or delayed a driver’s direct observation of the light(s).

2) Where were you? A determination of a vehicle’s spatial relationship to the intersection at the time the light was initially observed is required. Also required is knowledge of the cycling and timing of the traffic signal. The timing of the light cycle defines the time available for vehicles to legally and safely pass through the intersection.

3) How fast were you going? Knowing if a vehicle’s speed was varying or constant affects the degree of certainty of the determination.

4) Did you hear something? The identification of any sounds heard by a driver prior to the collision may provide insight into the spatial relationship between the involved vehicles. Especially important are sounds such as horns, sliding or skidding tires or any other sounds indicative of an impending collision.

5) Describe the damage to your vehicle. A description of the damage sustained by one or both vehicles may provide insight as to the spatial relationship of the vehicles when they entered the intersection. Knowledge of which vehicle entered the intersection first may be help helpful in making a determination.

After information relating to time, distance and speed has been identified and analyzed, verified numerical data is placed into appropriate mathematical formulae. A number of different equations can be used to calculate different aspects of the approach to the traffic signal. Once calculations have been completed the resulting answers are then considered in accordance with the timing and sequencing of the traffic signal; the damage sustained by the vehicle(s) and the sounds possibly heard prior to the collision. At that point a green light determination can be made.

The Westfield Investigative Group, LLC is a full-service accident investigation service that is able to determine who had the green light using traditional investigative and mathematically-based methodologies. Our investigative methodologies have been used successfully employed in both intersection accidents as well as other non-accident situations. We adhere to best practices and employ all appropriate means to attain favorable results for our clients. Please see our website www.westfieldinvestigative.com for additional information about us and the accident reconstruction and collision-related investigative services we provide.

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