There are a couple other very significant factors that have also affected the Transportation Sector’s carbon emissions, and likely to greater extents than recent new vehicle CAFE standards.  Probably one of the larger impacts has been the magnitude of the 2007-09 economic recession and historically very slow recovery.  Transportation Sector petroleum consumption peaked in 2007 and has been relative flat since 2010.  Yes, increased CAFE standards have helped contribute to this lower consumption, but this improvement is relatively small due to the fact that ‘new vehicle sales’ have also declined (at least 20%) and are slow to recover to historic levels, and ‘vehicle miles driven’ also declined due to the recession and are slow to recover and remain relatively flat.  Another factor that reduces the impact of CAFE mileage improvements is the fact that actual fuel economies are significantly less than (down about 20% lab. vs. actual) fuel efficiencies.  Refer to a past TEC Post: ‘Can the New CAFE Standards Deliver (Promised Benefits)?’.

Agreed, increasing oil prices have also contributed to reduced petroleum consumption; in combination to reduced Household incomes.  Since 2005 average gasoline prices have increased from $2.31 up to $3.58 per gallon recently.  This 55% or $1.27 per gallon increase definitely reduces the average Household’s ability to purchase the same level of motor fuels as they did before their average annual income dropped by almost $5,000 or over 8% since 2007.

What happened? Lindsay, what happened was George W. Bush’s term as President of the United States ended and he thankfully returned to his ranch in Texas to take up oil painting.

Bush was undeniably, unqualifiedly, and unabashedly the worst environmental president in U.S. history. For those who aren’t aware of it or are still in denial, an exhaustive list of why can be found here. Most of his “crimes against nature” are outside the scope of your post. Here are three which aren’t:

• The EPA under Bush-appointee Christy Todd Whitman spent $1 million on “public service” messages portraying a man attempting to lower his auto emissions as a geeky, hapless nerd
• In 2003 Bush’s economic stimulus plan included a $100,000 tax credit for business owners who purchase any vehicle weighing 6,000 pounds or more when fully loaded. The bill was passed by Congress.
• Bush Energy Secretary appointee Spencer Abraham, a former one-term senator from Michigan and cash-rich from auto company contributions, led the administration effort to scuttle fuel-economy standards and allow SUVs to escape fuel-efficiency minimums.

Bush’s tenure was centered part-and-parcel around encouraging the use of more oil, ostensibly with the cynical purpose of enriching the supporters and entities who got him his job. The war he started to that same end will hopefully result in war crimes one day, but this is also outside the scope of your post. A relative assessment of his legacy would put his artistic talent on par with Picasso.