When I was at university getting from class to class between buildings meant fighting your way along a footpath against a flow of students coming the opposite direction. Solutions? You could widen the path (more concrete) or redesign the pathway using a similar width of concrete split into two paths, one for each direction.
Here is an illustration:
There is no need for signs. People will naturally walk taking the most direct path towards their goal. In this way, the two paths end up being effectively one way. In addition, the area between the two paths may be grassed and treed.
The result – no additional concrete and no signs – and no dodging oncoming traffic!
This design occurred to me in 1982 or ’83 and it has only taken me 24 years to get it written down. If anyone has seen this idea implemented anywhere – I would love to see pictures. Leave a comment.