mileage based user fees
Varied toll rates on select corridors raise more revenue and manage traffic better than flat VMT toll - modeling of LA traffic
2013-01-18: Modeling by a CDMSmith/Parsons Brinckerhoff team for the Southern California Association of Governments (SCAG) suggests that congestion in the greater Los Angeles area will be effectively reduced and toll revenues maximized with a combination of (1) regionwide variable tolls (2) premium service on a limited or 'strategic' network of toll express lanes (3) downtown cordon pricing including the 'box' of freeways around the central business district.
Mileage based user fees (MBUFs) have little support in the US Congress. MAP21 the recent two year authorization bill provided for some research money for MBUFs also known as vehicle miles traveled charges or taxes. MBUFs are a kind universal toll and are the favorite new funding device of most transport funding commissions and studies by policy wonks in thinktanks.
Gas taxes are in decline as a revenue source due to near stagnant miles traveled and improving fuel economy.