In the UK at rush hour, congestion is an utter headache. This day and age 3 lane motorways is just not adequate enough. They should either extend all motorways by two more lanes or consider building a double decker motorway system.
On top of this I think cars this day and age should come with an option to switch to entirely electric power when on a motorway and the motorways could then be designed to recharge cars as they drive along them. I think to do something like that on all roads or carriageways is far too expensive and silly but major motorways could potentially do this. When the cars leave the motorway they could then switch back to petrol.
Cars though of course would need to be charged via number plate recognition every time they enter onto the motorways but its saves you money on petrol so it wouldn't be like you are losing money because you are saving petrol.