Lies, Damned Lies and Statistics – the Reality of Reporting MPG

By Jon LeSage

In this day and age of aggres­sive, ambi­tious tar­gets for fuel econ­o­my increas­es and green­house gas/CO2 reduc­tions in the US, Euro­pean Union, and else­where, it’s not shock­ing to see skep­ti­cism and inves­tiga­tive report­ing revved up by Con­sumer Reports and oth­er sources. Hyundai and Kia are going through the ringer, and now Ford Motor Co. is in the spot­light (and the Envi­ron­men­tal Pro­tec­tion Agency, which cre­at­ed the num­bers) over its claim that the 2013 Ford C-Max Hybrid gets 47 miles per gal­lon in com­bined city/highway fig­ures.

Con­sumer Reports put a lot of mileage on the 2013 Ford C-Max and Fusion Hybrid, get­ting 37 com­bined mpg in the C-Max and 39 com­bined in the Fusion Hybrid. For the Con­sumer Reports team, it was the largest dis­crep­an­cy between over­all-mpg results and the esti­mates pub­lished by EPA among any of the cur­rent mod­els. They’re about 20% low­er than the EPA rat­ing.

The report pushed EPA into review­ing the mileage claims of the two new Ford mod­els. It wasn’t long after the inves­ti­ga­tion into the Hyundai and Kia scan­dal, so EPA was sen­si­tive about appear­ing to drag its heals on the mat­ter; the agency doesn’t know when it will release results from its inves­ti­ga­tion.

Ford’s mar­ket­ing chief Jim Far­ley has dis­missed the claims. “Ear­ly C-Max Hybrid and Fusion Hybrid cus­tomers praise the vehi­cles and report a range of fuel econ­o­my fig­ures, includ­ing some reports above 47 mpg. This rein­forces the fact that dri­ving styles, dri­ving con­di­tions, and oth­er fac­tors can cause mileage to vary,” he said.

Ford’s group VP glob­al prod­uct devel­op­ment, Raj Nair, reassert­ed a sim­i­lar com­pa­ny stance recent­ly to Ford is stand­ing by the rat­ing and added that, “we absolute­ly agree with EPA that hybrids are far more vari­able in the test cycle com­pared to real world dri­ving con­di­tions in con­ven­tion­al vehi­cles. We are work­ing close­ly with the agency to deter­mine if any changes are need­ed for the indus­try rel­a­tive to hybrid vehi­cle test­ing.”

Nair thinks a lot of it has to do with dri­ving style – a “lead foot” com­bined with envi­ron­men­tal fac­tors vary mileage per­for­mance, he said. The dif­fer­ence between 75 mph and 65 mph can pro­duce a 7 mpg dif­fer­ence in fuel econ­o­my; out­side tem­per­a­ture dif­fer­ences can change the num­bers by 5 mpg, and break­ing in the vehi­cle through its first 6,000 miles affects mileage, he said.

EPA is adding equip­ment to its Michi­gan lab­o­ra­to­ry that might be attempt­ing to get away with a lie. By next fall, the EPA expects to be fin­ished with a five-year upgrade to its Nation­al Vehi­cle and Fuel Emis­sions Lab­o­ra­to­ry in Ann Arbor, Mich. All eyes are watch­ing.



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