The operator of the expressway connecting Hanoi and the port city of Hai Phong are seeking police help to stamp out the constant throwing of rocks at vehicles on the road in recent days.
Le Xuan Tu, deputy chief manager of the Hanoi-Hai Phong Expressway, said the attacks have been occurring regularly in Hai Duong Province and he has complained to the local police.
He said there had been at least five rock attacks within one and a half hours Friday night which broke glasses and damaged vehicles.
One driver said a man who threw rocks at his car was standing on the median very close to vehicles traveling on the road.
Tu said several people were caught for throwing rocks last year, but were let off because they were minors.