That's rated as the Number 1 aviation safety concern here in America. Every pilot safety meeting I attend (2-3 a year) spends a good amount of time stressing the importance of knowing your position on the ground. This isn't easy at major airports. The runway and taxiway diagrams can get pretty confusing sometimes. Throw in thick fog like in today's accident and the problem gets much worse. There's a pressing need for airport ground surveillance radar but it keeps getting pushed to the back burner. There have been several major crashes over the years due to collisions on the ground including the all-time worst airline accident back in the 1970s when two 747s collided, killing hundreds of people.