Jason Notte

Diesel has made long U.S. journey from dirty, smoky highway haze favored by truckers and coal rollers to favored alternative fuel of the eco-conscious.

Long favored on European roads, cleaner-burning diesel vehicles have seen sales increase 25% during the first six months of 2014 compared with the 4.2% growth of the overall U.S. auto market, according to data compiled by Cars.com and Baum & Associates. Diesel vehicle registrations in the U.S. have increased 30% since 2010 compared with a 3.6% uptick in vehicle sales during that same period, according to vehicle data group IHS Automotive.

Among the states, IHS Automotive notes that Texas has the most diesel vehicle drivers, at more than 837,000. California comes in second with 609,000, while Florida rounds out the Top 3 with 318,000. The fastest growth, however, comes in North Dakota (with diesel sales up 24% in 2013), Washington, D.C., (up nearly 16%) and Illinois (14%).

While the top diesel-driving states still included Wyoming (10.8% of all vehicles), Montana (8%) and Idaho (7%) — where diesel pickup trucks make up much of the fleet — diesel cars and SUVs are making up a greater portion of the mix in Delaware (up 10% in 2013), New Jersey (8.5%) and Ohio (8%).

Allen Schaeffer, the executive director of the diesel-backing auto industry group Diesel Technology Forum, argues that today’s diesel vehicles are 30% more fuel-efficient than their gas counterparts and will play a big role in reaching new federal fuel efficiency standards that will require a 54.5 miles-per-gallon average by 2025. It’s about the one fuel U.S. drivers are embracing. The Department of Transportation notes that U.S. drivers, who had been racking up a steadily increasing number of miles since the 1970s, started cutting back in 2008 and never returned to that level.

To get some idea of just how far diesel vehicles have come, we consulted the Department of Energy and found the 10 most fuel-efficient diesel vehicles on the market. While German automakers dominate the list, U.S. automakers are starting to make their presence known with diesel versions of Jeep’s Cherokee and the Ram 1500 both just missing the cut: