Solomon curve
graphical representation of the collision rate of automobiles
The Solomon curve is a graphical representation of the collision rate of automobiles as a function of their speed compared to the average vehicle speed on the same road. The curve was based on research conducted by David Solomon in the late 1950s and published in 1964. Subsequent research suggests significant biases in the Solomon study, which may cast doubt on its findings.
Initial research
In 1964, Solomon researched the relationship between average speed and the collision rates of automobiles. 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 of more than 10,000 collision-involved drivers and their vehicles and how other roadway, driver, and vehicle characteristics affect the probability of being involved in a crash. He 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 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 examined the impact of speed variation on crashes involving two or more vehicles. The Cirillo data produced a U-shaped curve similar to the Solomon curve.
This brief starts where responsible research should: with the source description of “Solomon curve” as graphical representation of the collision rate of automobiles. Everything that follows is an evidence route, not borrowed authority.
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The subject matters to the general reference register because the source frames it as graphical representation of the collision rate of automobiles. Its deeper value depends on whether names, dates, institutions and citations support that framing.
The citation trail is more important than the brevity of the summary: it shows where individual claims can be examined in context. The source revision retrieved here is dated May 13, 2026. The linked authority identifier is Q7558788. None of the 0 selected statements returned an explicit reference. The first chronological checks are 1964 and 1968.
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This entry incorporates text from “Solomon curve” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.