When I was young I visited our city's traffic department, they had a map on the wall of all the traffic accidents. In the city I lived in the older parts were a

When I was young I visited our city's traffic department, they had a map on the wall of all the traffic accidents. In the city I lived in the older parts were a very regular grid, and the new parts were cul-de-sacs. Almost all the traffic accidents were at intersections in the grid parts of town.