The Crash That Happens at Ten Miles an Hour

Heavy congestion produces a particular kind of collision: low speed, rear-end, and far more expensive than the dent suggests.

It is the signature crash of the corridors that back up daily: the 405 through the Sepulveda Pass, the 5 through Santa Ana, the 91 between Corona and Anaheim. Traffic there moves in waves: a driver half a mile ahead touches the brakes, and the pulse reaches you as a full stop with nothing visible to explain it.

Why a small impact costs real money now

Modern bumpers hide a lot. Behind the cover sit parking sensors, radar modules for adaptive cruise control, and cameras feeding driver-assistance systems. A low-speed knock that once meant a bumper cover and paint can now mean replacing sensors and recalibrating systems afterward — and the recalibration is its own line on the estimate.

Fault in rear-end collisions

The following driver is generally presumed responsible, on the reasoning that maintaining enough distance to stop is their job. That presumption isn't absolute — a driver who cuts in and brakes hard, or whose brake lights don't work, changes the picture — but it's the starting point.

The rule underneath it is Vehicle Code section 21703: a driver shall not follow another vehicle more closely than is reasonable and prudent, having due regard for speed, traffic and the condition of the roadway. It fixes no distance. The gap gets judged on the day.

The injury dimension

Neck and back injuries occur at surprisingly low speeds, and symptoms often appear a day or two later rather than at the scene. This is why "I feel fine" at the roadside isn't a good reason to skip documentation, and why medical payments coverage is worth understanding before you need it.

Following distance is the whole game

In stop-and-go traffic the temptation is to close the gap because someone will take it. The gap is the only thing that converts a collision into a non-event. Nothing else available to you works as reliably.

If you're hit

Photograph the damage on both vehicles even if it looks trivial, exchange the required information, and get checked if there's any symptom at all. Damage estimates on modern cars routinely exceed what the scene suggested.

There is a DMV step people miss, too. Vehicle Code section 16000 requires a report to the DMV within 10 days of a collision causing injury, death, or property damage above the threshold the section sets, which a modern bumper repair clears without trying. Your agent can file it; it is separate from telling your insurer.

The chain reaction, and who pays whom

Three and four-car chains are ordinary here, and they confuse people: the physical sequence and the liability rarely line up. If the car behind you pushes you into the car ahead, you were struck first and shoved second. That is not the same as failing to stop, even though your front bumper is damaged and the driver ahead is looking at you.

Protecting yourself takes two minutes. Photograph the front and the rear of every car involved, not just the two nearest you, and note the order they ended up in. One push leaves a different pattern from two impacts, and those photographs are usually the only record of which happened.