The Surprising Truth About Traffic Speed and Crashes

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Solomon’s Curve and Motorcycle Safety: Does Riding with the Flow Really Matter?

Ever feel like you’re either flying past traffic or everyone’s flying past you?

Back in the 1960s, researcher David Solomon studied over 10,000 crashes and came up with what’s now called Solomon’s Curve. It shows that your risk of a crash goes up the farther your speed is from the average speed of traffic — whether you’re faster or slower.

Today we’re going to explore whether Solomon’s Curve still holds up, what newer research says, and most importantly — what it means for you as a rider trying to stay safe on the road.

What Is Solomon’s Curve?

Solomon’s Curve comes from a study done in 1964 by David Solomon. He looked at over 10,000 crashes and compared the speed of each vehicle to the average speed of traffic on the same road.

What he found was surprising — if you were right around the average speed of traffic, you were the least likely to crash. The farther your speed got from that average — either faster or slower — your crash risk increased.

When graphed, the results formed a U-shaped curve, which is why it’s often called the “crash risk curve.”

“Go with the Flow” — The Common Advice

This is where that familiar advice comes from — “ride with the flow of traffic.”

The idea is simple:

Matching the speed of traffic reduces conflicts with other vehicles.
Fewer conflicts typically mean a lower risk of being involved in a crash.

But like most safety research, Solomon’s work wasn’t perfect.

Criticisms of Solomon’s Curve

One of the biggest criticisms is that the study grouped together vehicles traveling slowly with those slowing down to turn.

When researchers later removed those turning vehicles from the data, the left side of the U-shaped curve flattened out. This suggested that simply riding a little slower than traffic might not be as risky as Solomon’s original curve made it look.

What Newer Research Says

Other studies over the years have confirmed key parts of Solomon’s findings, especially that going faster than traffic raises your crash risk.

However, newer research shows that riding slower than average still carries some risk — but likely not as much as Solomon’s original curve suggested.

The Big Takeaway for Riders

Most experts today agree on this:

The farther you ride above the average speed of traffic, the higher your crash risk.
Riding much slower than everyone else still puts you in danger, but the risk isn’t quite as bad as Solomon thought.

The safest strategy?