Am I missing something here? Already our motorways / highways are not being used at this higher capacity but when something bad happens there is no redundancy.

Am I missing something here? Already our motorways / highways are not being used at this higher capacity but when something bad happens there is no redundancy. Everything grinds to a halt. What's the desire to make this worse? Also does it not put even more pressure on the roads leading to the highway? - increasing congestion to the point where having higher usage of highways is pointless.