The Speed Factor: Pre-Crash Speed Distribution in AV Incidents
1,756 incidents at 0–25 mph, 613 at 66+ mph. Low-speed crashes dominate but high-speed ones kill. Average: 36 mph.
Speed kills — that's the oldest rule in traffic safety. But the AV incident data adds a twist: most autonomous vehicle crashes happen at low speed. A total of 1,756 incidents occurred at 0–25 mph, dwarfing every other speed bracket. Yet the 613 incidents at 66+ mph account for a disproportionate share of fatalities. The average pre-crash speed across all incidents: 36 mph.
36 mph
Average pre-crash speed across all 6,215 AV/ADAS incidents in the NHTSA database.
The Speed Breakdown
| Speed Range | Incidents | Share | Severity |
|---|---|---|---|
| 0–25 mph | 1,756 | ~38% | Low |
| 26–45 mph | ~900 | ~20% | Moderate |
| 46–65 mph | ~750 | ~16% | Moderate-High |
| 66+ mph | 613 | ~13% | High / Fatal |
Why Low-Speed Crashes Dominate
The 0–25 mph bracket is inflated by two forces. First, Waymo's robotaxi fleet operates almost entirely in urban environments at low speeds. With 1,729 total incidents — mostly in San Francisco and Phoenix city streets — Waymo alone accounts for a huge chunk of the low-speed count. These are typically minor fender benders: getting nudged in traffic, scraping a parked car, or rolling into a vehicle at a stop sign.
Second, many Tesla ADAS incidents involve Summon and parking features that operate at walking speed. A Tesla creeping through a parking lot and bumping a pillar registers as an incident at 3 mph.
Why High-Speed Crashes Kill
The physics are unforgiving. Kinetic energy scales with the square of velocity — a crash at 70 mph delivers nearly 8x the energy of one at 25 mph. The 613 incidents at 66+ mph are overwhelmingly Tesla Autopilot crashes on highways. These include the most publicized AV fatalities: vehicles striking stationary fire trucks, crossing medians, or failing to navigate highway curves.
While the 66+ mph bracket represents only ~13% of incidents, it accounts for an estimated 40–50% of all AV-related fatalities. This is where the Tesla Autopilot safety question is most acute.
The 36 mph Average
The 36 mph average pre-crash speed is pulled down by the massive volume of low-speed urban incidents. If you isolate Tesla ADAS incidents only, the average is likely higher — perhaps 45–50 mph — reflecting more highway usage. If you isolate Waymo ADS incidents, it drops to perhaps 15–20 mph, reflecting urban robotaxi operations.
What This Means
The dual problem
AV safety has two distinct challenges: a volume problem at low speeds (lots of minor crashes, especially from robotaxis) and a severity problem at high speeds (fewer crashes but more deaths, especially from ADAS on highways). Solving one doesn't solve the other. Regulators need to evaluate both — and the speed data on the dashboard makes the case clearly.
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