green car sales graphic

Advanced-powertrain vehicle sales continued to warm up with the weather, as Americans in May stepped up their purchases of hybrids, electric vehicles, plug-in hybrids and diesels.

US green-car sales for May rose 14 percent from a year earlier to 68,189 units, while plug-in vehicle sales jumped 90 percent from May 2013 to 10,833 vehicles. And those numbers understate the year-over-year improvement because Tesla Model S sales figures aren't factored in (Tesla only discloses quarterly numbers and doesn't break out overseas sales, making reasonable estimates increasingly problematic with more and more of Tesla's sales coming from overseas).

The big story is Nissan, which saw sales of its all-electric Leaf jump 46 percent.

The big story is Nissan, which saw sales of its all-electric Leaf jump 46 percent from a year earlier to a monthly-record 3,117 vehicles. Also now added to the mix is the BMW i3, which racked up 336 sales during its first month of recorded US sales.

Toyota also fared well, as the Japanese automaker started to reverse alt-fuel vehicle sales declines from earlier in the year. Sales of the four Prius variants rose 14 percent from 2013, up to 26,793 vehicles, while Camry Hybrid and Avalon Hybrid sales were both up more than 20 percent. Overall, Toyota and Lexus combined boosted year-over-year green-car sales 13 percent to 38,464 vehicles.

Even Insight hybrid sales increased by 16 percent to 493 units.

Honda continued to make advances on the green-car front, selling 1,530 of its newer Accord Hybrid model and even Insight hybrid sales increased by 16 percent to 493 units. Honda's green-car sales jumped 76 percent from a year earlier to 2,969 vehicles.

Ford also did well in May, boosting green-car sales by 21 percent to 10,121 vehicles. Fusion Hybrid sales jumped 39 percent to 4,641 units, Lincoln MKZ Hybrid sales surged 58 percent to 1,128 vehicles and Fusion Energi Plug-in Hybrid sales tripled to 1,242 units.

Overall, GM's green-car sales fell 24 percent from 2013.

Such sales jumps more than offset the impact of lower alt-fuel sales from General Motors and Volkswagen. While GM's Chevrolet Volt extended-range plug-in sales rose 4.8 percent to 1,684 units, sales of mild-hybrid models like the Buick Regal eAssist and Chevrolet Malibu ECO plunged. Overall, GM's green-car sales fell 24 percent from a year earlier to 3,377 units. VW's diesel and hybrid sales fell 13 percent from a year earlier to 7,799 units.

As for lower-volume green-car makers, Audi's diesel sales quadrupled to 1,587 units, while Porsche hybrid sales more than doubled to a still-small number of units - 128 - and Mercedes-Benz's Smart division sold 206 of its ForTwo ED electric vehicles. Mitsubishi i battery-electric sales fell 61 percent to 35 units.