Side-impact collisions
Junctions, right of way and who went first.
The crash was light. What killed was the unprotected tree
The case
- Two cars touched at a highway access that served both a fuel station and a municipal street. The first contact caused minor damage.
- One of them spun, hit the kerb and a tree and fell down a drop of about 8 m. The driver died.
- The 45° embankment had trees with trunks over 40 cm and no barrier or guardrail, which standard NBR 15486 requires in this case.
- Federal highway police data show 23 accidents in four years at the spot, and 50 between 2018 and 2024, most of them from entering the road without seeing other vehicles.
How we helped the client
We were hired to reconstruct the dynamics from the report and the photos. The place of first contact was not recorded, and the report’s braking mark began after the junction.
The 25 m spin marks show the car was going at least 67 km/h in a 50 km/h section, with a speed camera 200 m before the spot.
We asked the reverse question: at 50 km/h the car would have slid only about 12.7 m and stopped before the tree, which was 25 m away. Speed was decisive, but the road also played a part.
Speed, from the marks on the asphalt
The distance to the tree and how far the car would have gone
The event was caused by the imprudence of the driver of the car travelling above the limit. Contributing causes were the lack of protection devices on the embankment and the irregular access, which combined a commercial entrance and a public street without proper treatment.