“The Volt had its strongest sales month to date in March, with sales of more than 2,000 vehicles. Sales nearly doubled from January to February and that trend continued into March,” GM wrote yesterday. February Volt sales were at 1,023, while March sales reached 2,289. As gas prices increase and people see more and more stories about clean cars such as the Volt, Leaf, and Prius, sales are rising. Nissan Leaf sales increased from 478 to 579 for the same time period, and its 2012 sales at the end of March were 1,733, more than three times the 2011 figure of 452. Toyota sold 891 Prius Plug-In Hybrids in that car's first full month on the market--or about 3 percent of the 28,711 Priuses sold in March.