People do not have to cross a busy road to get from one grid square to the next one, because the roads go over bridges and people can cross safely under them. The paths that go under the roads and between the houses are called Redways because they are red in colour. Only people on bicycles and people walking are allowed to use them. Cars, lorries and motorbikes are not allowed to go on them. So people could cycle all the way across the city and never have to go on a busy road.