These graphs show the changes in emissions, emissions drivers, and policy in the Transportation sector in the US
Emissions Emissions and transport activity
Both passenger and freight travel increased significantly since 1980. Passenger travel dropped significantly during the recession.
Emissions Drivers Emissions intensity
Large gains in vehicle engine and transmission efficiency did not result in significant fuel efficiency gains, as cars became heavier. There was little shifting between transport modes (not shown).
Policy Corporate average fuel economy standards
Fuel efficiency standards remained largely unchanged for over two decades. Only recently have standards for passenger vehicles been revisited.