Feature Request - Block a tile.

An option to tell vehicles not to pass a certain square. Say you have a bus route that, later on, a competitor runs a train line over a piece of the road. Although there are alternative routes, the bus might take the route with the train crossing, leading to the risk of an accident.

If you could "mark" certain squares as no-go areas (from an option in the build toolbars, shown with a "no entry" red icon overlaying the square's graphic) that no vehicle of yours will go over in any circumstance, that would be useful. Obviously your competitors would not know where your no-go areas were, or be affected by them.

On roads, it would work like the construction squares when you fund road reconstruction. On railroads, the square itself would act as if it had no rails on it and would also turn any signals pointed towards it red. On water, it would act as if an object were on that tile. I don't think it would work (or be required) for air vehicles and they could ssafely ignore it (however, being able to mark an airport as "closed" would be very useful for upgrading airports).

When there is a collision between trains, you could "close" off the tiles leading to it to prevent further collisions or trains waiting to use that path. When there is a rail crossing over a road, you can stop your vehicles wandering over it. I can see it being quite useful.