2. Background
In most countries, greenhouse gas emissions from transportation are rising
or at best declining gradually
0
500
1000
1500
2000
2500
2005 2010 2015 2020 2025 2030 2035
Projected US Transportation Sector Emissions
(million metric tons carbon dioxide)
AEO 2019
AEO 2009
Sources: Energy Information Administration (EIA)
Annual Energy Outlook (AEO) 2009 and 2019
3. Why are us emissions expected to decline gradually?
1
1.05
1.1
1.15
1.2
1.25
1.3
1995 2000 2005 2010 2015
US HouseholdVehicle MilesTraveled (1995 = 1)
FHWA NHTS Prediction
Sources: Federal Highway Administration, National Household Travel
Survey, and Leard et al. (2018)
0
0.2
0.4
0.6
0.8
1
1.2
2015 2020 2025 2030 2035 2040
Index: 2017 = 1
Vehicle miles traveled
Fuel consumption (gallons)
Fuel consumption rate (gallons per mile)
Source: EIA AEO 2019
4. Policies affecting vehicles and driving
Fuel economy/GHG standards for new vehicles
• About half of all vehicles globally
Taxing vehicles with high GHG emissions
• Europe and a few other countries
Restricting private ownership
• Primarily, large Chinese cities
5. Lessons from recent case studies
Europe: CO2-linked taxes on vehicle purchase or registration
• Taxes tend to favor diesel fuel vehicles over gasoline, increasing sales of
diesels
• Unintended consequence: Local air pollution roughly offsets climate
benefits
Beijing: Vehicle ownership restrictions
• Reduced new vehicle ownership by roughly half
• Proportional drop in driving, mostly shifting to bus and subway
• But: lower fertility and female employment rates
6. What have we learned?
Fuel economy/GHG standards have been effective, with apparently
moderate costs
Vehicle taxation can be effective, but need to watch out for trade-offs
between GHG and local air pollution (for example, gasoline vs. diesel fuel)
Restricting vehicle ownership has reduced VMT, but driving restrictions
have been less effective