Establishing new sources of transportation revenue based on motor vehicle use of public roadways.

HB 1921 establishes a mileage-based road usage fee system to replace declining fuel tax revenue, directly affecting vehicle owners - starting with electric/hybrid vehicles in 2027 and phasing in conventional vehicles based on fuel efficiency by 2035. The bill creates a voluntary program for EVs/hybrids (2027-2029) and a mandatory program for increasingly efficient conventional vehicles (starting 2029), replacing existing registration fees like those in RCW 46.17.323/324. Fees are calculated per mile driven, with privacy protections for location data emphasized as a core requirement. The phased approach aims to maintain current transportation funding levels while adapting to fuel-efficient vehicle adoption.