Can anyone describe vintage car club straight-line navigation?

Answer 1

It is a method for giving navigation instructions, The route isn't a map, its a straight line running from the bottom of the page to the top. Each interection is marked with lines (roads) coming off the straight line to the right and or left. These roads represent the ones you don't travel on ( but may not point in that actual direction). It may help to imagine how would create one. Imagine laying a piece of string along a map of the route to be taken. At each intersection attach small strings to represent streets you don't go down. Now pull the string tight (making sure your side streets don't cross over the "straight line") so that your route is a straight line and the side-streets come off it. These are the instructions that the navigator gets. The navigator should call out the roads that you won't go down eg "Leave 1 on left". This can be an instruction to go past one road running off to the left or an instruction to turn right at a T intersection with roads running left and right.