A truck manufacturer can be held accountable for designing a windshield that wasn’t strong enough to withstand a piece of concrete falling from a highway overpass, the California Court of Appeal recently decided.

The truck driver suffered severe brain injuries when a 2.5-pound piece of concrete dropped by a 15-year-old smashed through his windshield and struck him in the head.

The truck manufacturer, Navistar, argued that it wasn’t responsible because the teenager had deliberately thrown the concrete and caused the injury.

But the court said the manufacturer may have had a duty to design a windshield capable of withstanding such an impact, and it didn’t matter whether the falling object was thrown deliberately or fell by accident.