How the EPA gets there
With all the hubbub lately about falsified mpg claims and lawsuits pertaining to MKZ hybrids and other Ford/Lincoln offerings I thought it would be a good time to check in on how the EPA comes up with the mileage figures we all weigh so heavily into our purchase decisions, have a look:
• In a lab the drive wheels are pulled onto a dyno to simulate driving dynamics.
• Driver runs the car through a standardized driving routine attempting to simulate real world trips.
• A schedule stipulates the speed the car must travel at during every second of testing
• An outlet hose captures exhaust gases and measures them to calculate the amount of fuel consumed.
Things to keep in mind:
• Outlet hose measurement cannot effectively capture mileage estimates for Fuel cell, electric or hybrid vehicles
• No idle time that simulates red light fuel waste
• Vehicles are babied, light acceleration and diminished speeds ( about 50 mph for highway test)
• City test lasts 5 minutes, Highway test lasts 12 minutes
• City test done with cold engines, Highway test done with warm engines
Looking at this list its very easy to see where gaps in mileage claims come from...