User:PhillipSoloMoN/Solomon Curve

The Solomon Curve is the graphical representation of the research conducted by David Solomon in the late 1950s and published in 1964.

The Original Research
In 1964, Solomon researched the relationship between average speed and collision rates of  automobiles and plotted the results. While others have attempted to quantify the relationship between average speed and collision rates, Solomon's work was both the earliest and best known. Solomon conducted a comprehensive study on crashes and how other roadway, driver, and vehicle characteristics affect the probability of being involved in a crash. Solomon found that the probability of being involved in a crash per vehicle-mile as a function of on-road vehicle speeds follows a U-shaped curve (see figure to the right) with speed values around the median speed having the lowest probability of being in a crash. Although typically called the Solomon curve, the U-shaped curve has also been referred to as the Crash Risk Curve.

Subsequent Research
In 1968, Julie Cirillo conducted a similar study of 2,000 vehicles on interstate highways that addressed speed variation’s impact on crashes that involved two or more vehicles. The Cirillo data represented a U-shaped curve similar to the Solomon curve.

Theoretical Foundation
Hauer provided a theoretical foundation for the Solomon curve in 1971 – “for example, if I drive at 45 mph, while the median of the pack is 60 mph, how many cars will pass me in an hour and hence have a chance to collide with me” – that showed that the theoretical distribution was nearly identical to the Solomon curve.