HARRISBURG — Pennsylvania’s Senate Transportation Committee chairman wants to boost spending on highways and mass transit by almost 50 percent a year, primarily by raising a wholesale gas tax.

Sen. John Rafferty’s plan released today follows Gov. Tom Corbett’s more modest proposal in January.

The Montgomery County Republican envisions raising $2.5 billion a year for highways, bridges, airports, mass transit, ports, rail freight and walking and biking routes. It phases in over five years revenues that include higher fees on licenses, registration and traffic violations.

Key Senate Democrats are expected to support it. However, it could have rough sledding in the more conservative House of Representatives.

The Department of Transportation says repairs are needed to about 20 percent of the state-maintained highways and bridges. Meanwhile, public transit agencies routinely battle budget deficits.