Consumer Groups Call for Prohibiting Only City or Highway EPA MPG Numbers in Advertisements

A new survey shows that consumers believe the use of highway-only figures is deceptive

Consumer Groups Call for Prohibiting Only City or Highway EPA MPG Numbers in Advertisements
Image: Toyota
September 9, 2016

The Consumer Federation of America (CFA) and the Center for Auto Safety are calling for the Federal Trade Commission (FTC) to prohibit automakers from using only highway or city EPA (Environmental Protection Agency) MPG (miles per gallon) estimates in advertising because the practice may be deceptive.

In reviewing advertising guidelines regulating advertising that uses MPG figures, so far the FTC has found no problem with allowing manufacturers to promote highway estimates alone.

The Problem

"We believe that allowing the promotion of just the highway EPA mileage estimate is misleading and deceptive for a number of reasons," said Jack Gillis, automotive expert at the CFA and author of The Car Book. "First of all it is impossible to infer overall fuel economy performance from just the highway (or city) EPA MPG rating. Our analysis of over 1000 EPA mileage ratings for the 2016 vehicles demonstrates that there is no relationship between a particular highway rating and its corresponding city or combined rating."

When looking at any one highway number, the corresponding city figure can differ by as many as 17 MPGs with 14 different ratings. Therefore, consumers cannot infer the corresponding city or combined MPG correctly using the highway-only MPG currently allowed by the FTC.

The CFA found numerous examples of this problem. While the Hyundai Sonata SE and the Toyota Camry Hybrid XLE/SE received a highway MPG rating of 38, there is a 13 MPG difference in the city MPG ratings of each: 25 for the Sonata and 38 for the Camry. Furthermore, a 10 MPG difference appears when comparing the combined MPG ratings of each vehicle: 30 for the Sonata, 40 for the Camry. As this example implies, allowing vehicle manufacturers to promote the highway MPG alone could easily deceive consumers into the belief that the two vehicles are equally fuel efficient.

Costs to Consumers

Consumers may feel real consequences in their bank accounts and budgets if they depend solely on the highway number. Using a gas price of $2.12 per gallon and a typical 15,000 miles driven per year, the CFA calculated that a difference of 10 MPG in the combined ratings between the Chevrolet Impala Limited and the Lexus NX 300h may cost consumers $452 per year when each vehicle has a highway rating of 31 MPG. If the price of gas rose to $3.15, the cost would be more than $671.

Consumers Believe the Highway EPA Estimate Alone is Deceptive

From August 18-21, the CFA conducted a nationwide consumer opinion survey to determine what consumers believe about automakers' advertising practices. Sixty-four percent of the respondents said that they believe that allowing manufacturers to advertising the highway EPA MPG alone is misleading, and 43 percent said that their behavior as consumers would be affected by the inclusion of both the highway and city figures in advertisements as opposed to the highway figure alone.

"This behavior change is one reason why car makers don't want to provide both city and highway numbers," said Gillis.

Consumers were also asked which of the disclosure options for MPGs auto advertisers ought to be required to include when making a claim about vehicle fuel economy. Sixty-five percent responded that both city and highway figures ought to be included; 23 percent said the combined estimate should be given; six percent indicated the city number alone; and three percent wanted only the highway figure.

Consumers Need the Full Story

"What is particularly disconcerting is that the FTC has essentially determined that consumers believe that they can infer expected performance from a single number," commented Gillis.

Consumers should not, says the CFA, try to make the assumptions that the FTC claims they can. This is because most often there is not a relationship between city and highway figures. For this reason, automakers need to use both city and highway figures, the combined figure, or even all three when they promote fuel efficiency performance in their vehicles.

"Because the combined does consider the varied relationships between highway and city MPGs," notes the group, "it provides consumers with a reasonable basis for vehicle comparison as well as their own expected results."