City Directions

When driving through a city, an intersection usually offers one the choice of going straight on or turning left or right through 90 degrees. However some cities have diagonal roads, thus at intersections involving these one may be able to turn through 45 degrees (“half”) or through 135 degrees (“sharp”). Consider such a city with Avenues running north-south, Streets running east-west and Boulevards running diagonally. The central Avenue and Street are labelled Zero (A0 and S0). Other roads are labelled relative to these, thus A3W is the third avenue to the west of A0. There are 6 Boulevards — two passing through the centre of the city, and 4 others, one in each quadrant. The diagram below shows the northwest quadrant of a small version of such a city. The roads marked in grey are considered to be throughways. These are elevated for most of their length, thus it is possible to cross them easily, however they always intersect each other at a circle, which is shared by all other roads that meet at that intersection. You may only enter or leave them by turning left (sharp left in the case of boulevards). You may not stop on them for any reason. There are no restrictions on turns for other roads.