Urban highways solve a political problem. When you have voters that spend a hour or so a day stuck in traffic it's really easy to sell them the idea that a highway will reduce traffic congestion without them having to change anything about their daily routine (ie. take public transport, bicycle, walk)
Since the highway will only reduce traffic congestion for a short time it's something you can sell to the voters again at the next election.
Since the highway will only reduce traffic congestion for a short time it's something you can sell to the voters again at the next election.