Wow, the highways in Queensland are really long – and bendy! The Ipswich Highway road schematic was an interesting challenge. It required a lot of secondary road detail, it had an intersecting north-south freeway which also needed a schematic and it was very long.
When we are making road schematics we face two limitations: width of available drawing area and file size. Warning, techy explanation ahead: the maximum width of the drawing is fixed by the software and it controls the scale of the schematic. Therefore the amount of room available around the schematic for secondary road detail is limited to what is left over once the length has been best utilised* and the lane width has been established.
*Roads have to be straightened out and run horizontally regardless of their real geography. But they need to retain sufficient shape to suggest the real road because shape and landmarks provide context. This really is the key to the schematics: they must provide an explanation of the physical situation that results in the operators understanding the road without reference to geography or compass direction.
And then the second limit is file size. We are making really long, complex drawings that have loads of detail, landmarks, and signage in them, yet the file size has to be relatively tiny! So everything that goes onto a schematic has to have a good reason for being there. Landmarks have to be simple yet recognisable and the construction of the drawing has to be as efficient as possible.
Limitations make design much easier. By narrowing down the scope of what can be done and what is achievable, decisions about what should be included are made more intelligently – and we get to ask our favourite question more often: Why?