Converting on-street parking can help to increase capacity but I don't think you can convert a lot of parking lots into roads. And where real estate prices are

Converting on-street parking can help to increase capacity but I don't think you can convert a lot of parking lots into roads. And where real estate prices are high, they're often underground anyway. Making more efficient use of the roadway is great but they'll probably not more than double efficiency (as long as not all cars are self driving and the road is also used by pedestrians), so doubling the number of trips will still increase congestion.