The road as the cause
When a defect in the road, not driver conduct, explains the accident.
A truck at 72 km/h and a 16 cm dip in the road
The case
- A tractor unit with a trailer loaded with oranges left the road and rolled over beside it, in the morning, just past a crest curve.
- The GPS tracker recorded, at the moment of the accident, no more than 72 km/h, below the 80 km/h allowed for heavy vehicles.
- The site survey found a 16 cm depression at the point where the driver said he lost control, and there the road’s cross slope changed.
- There were braking marks from other vehicles and records of crashes at the same spot, one of them identical. The A-19 depression sign was missing.
How we helped the client
The company that owned the load needed to know whether the driver had made a mistake. We went to the site, surveyed the road profile and cross-checked it against the tracker record and the tachograph discs.
We showed why a heavy vehicle with a high centre of gravity loses stability when the dip combines with an inconsistent cross slope: the rig sways and tends to roll over, even below the limit.
With no warning sign, the defect was unexpected for the driver. The opinion treats it as a contributing cause.
The road defect in profile
The speed, from the tracker
The cause was the depression in the pavement, combined with an inconsistent cross slope, which made the rig unstable and led to loss of control and rollover. The missing A-19 sign was a contributing cause.