Sales of the Toyota Prius rose right alongside gas prices in March 2011. During the month, 18,605 Prius models were sold. This was up 52 percent from the 11,786 units sold in March 2010 and an increase of 5,066 from February 2011. Toyota has now sold 1 million Prius hybrids here in the United States. The rise in sales of the best-selling hybrid mimic the trend set during the summer of 2008 when gas prices topped $4/gallon across the country.

Prius sales led the way for what proved to be a stellar March for Toyota and Lexus hybrid sales. Overall, Toyota Motor Sales sold 20,839 Toyota-branded hybrids and 3,900 Lexus hybrids. This is a 42.5 percent increase from March 2010 sales.

Toyota wasn’t the only company to see a surge in hybrid vehicle sales. The Honda Insight set a March sales record with 2,782 units sold, up 62.2 percent from last year. Honda also sold 441 Civic Hybrids and 1,685 CR-Z hybrids last month. Two of the most fuel-efficient Hondas also saw a surge in sales — the Fit posted an increase of 43.4 percent and Civic sales increased by 33.8 percent.

Nissan North America (NNA) also had a record-setting month. NNA sold a total of 121,141 vehicles in March; the best sales month in the company’s history. While February proved problematic for sales of the Nissan Leaf, the company redeemed itself with its March figures. During March, NNA sold 298 Nissan Leafs, up significantly from the 67 sold in February.

The other new electrified vehicle, the Chevy Volt, also saw a jump in sales. In February 2011, General Motors only sold 281 Chevy Volts. Last month, the company moved 608 new Volts.

Is it a coincidence that sales of hybrid, electrified and fuel-efficient vehicles increased as gas prices trended upwards? If gas prices begin to normalize, will automakers see these sales figures drop? If sales trends follow those set during the 2008 gas price crisis, then automakers will likely see a decrease in demand for fuel-efficient models once gas prices return to normal.