To save money, the shoulder was often not paved to the same thickness as the through lanes, so if vehicles were to attempt to use it as a through lane regularly, it would rapidly deteriorate. In Britain, shoulder running can occur during roadworks, and full depth construction is now standard. In some metro areas, road authorities also allow shoulders to be used as lanes at peak periods. However, rural shoulders often collects various bits of road debris that can make driving there less safe.