Look to General Motors Co.'s March sales numbers to see how Americans are adjusting to higher gas prices.
The once truck-centric Detroit automaker said that combined sales of its 12 vehicles that achieve an estimated 30 miles per gallon or better on the highway, under U.S. Environmental Protection Agency standards, topped 100,000 last month, the highest total in company history.
"Three years ago, about 16% of the vehicles GM sold achieved at least 30 mpg on the highway. Today, that number is about 40%," said Mark Reuss, president of GM North America.
GM will release more data Tuesday.
One example of GM's transformation is that in 2002, trucks accounted for 54% of sales, cars 43% and crossovers just 3%. Now, trucks represent just 34% of GM's sales, while cars account for 41% and crossovers 24%.
The share of more fuel-efficient vehicles will probably grow as GM launches its 2013 Cadillac ATS, the Chevrolet Spark and the four-cylinder 2013 Chevrolet Malibu, all of which are expected to achieve EPA estimates of 30 mpg highway or better when the ratings are released this year.
"GM's strategic investments in four-cylinder and turbocharged engines, advanced transmissions and vehicle electrification have been very well timed," Reuss said.
One wrinkle in GM's drive to sell more fuel-efficient vehicles is an investigation by federal safety regulators into fires breaking out in the 2011 model year Cruze, GM's bestselling passenger car.
According to complaints made with the National Highway Traffic Safety Administration, there have been at least two incidents in which the small sedan has caught fire while being driven. GM said it is researching warranty claims involving fires in at least 19 Cruzes.
With sales of almost 232,000 last year, the Cruze became one of the nation's most popular small cars, outselling rivals such as the Honda Civic and Ford Focus and only narrowly trailing the Toyota Corolla.
But analysts said the probe could dampen Cruze sales. The small-car segment of the auto industry is among the most competitive, and consumers have an ample selection of good vehicles from many makers to select from, said Jessica Caldwell, an analyst with Edmunds.com.
March is expected to be the biggest month for U.S. auto sales since August 2007.
"We are looking at a record-breaking month for many manufacturers in March, with Hyundai, Nissan and Volkswagen expected to have their highest unit sales ever in the U.S.," said Jesse Toprak, an analyst at auto information website TrueCar.