A car took an underpass in Mestre at high speed, invading the opposite lane and causing a head-on.
The two drivers were injured, in yellow code, while a mother and her son were involved in a third car and taken to hospital for checks, without damage.
On the spot Fire and Sanitary Brigade of Suem 118 and the Carabinieri for investigations.
According to an initial reconstruction, it was an undocumented man who caused the crash, probably fleeing in an Alfa Romeo Giulietta after leaving an area of shopping centers.
He would now be guarded in the hospital.
It is the second serious accident in Veneto in the space of 24 hours caused by a runaway car.
Yesterday in the Treviso area a 19-year-old without a license had become the protagonist of an escape from the Carabinieri by stealing three cars, knocking over a car from the Arma and instantly killing a cyclist overwhelmed as he passed before his arrest.