Traffic is awful because road owners aren't charging for access.
From an Economics standpoint, congested traffic is the same phenomenon as the old Soviet bread lines. A underpriced good is inaccessible in practice, since supply is way lower than demand at that price.
The solution is "Road Pricing", where drivers pay to drive. The price varies depending on what road, time of day etc. Maximum revenue should coincide with maximum throughput, giving everyone (ready to pay) a smooth and fast commute. It also provides incentives to build more roads where they are mostly needed.