US March new vehicle retail sales showed showing in the first three weeks of the month, continuing a trend of monthly double-digit year-over-year increases, according to JD Power and Associates, using real-time transaction data from about 8,900 retail dealerships throughout the country.

JDP predicts March retail sales at 991,900 units, for a seasonally adjusted annualised rate (SAAR) of 10.9m. This would bring the selling rate for the first quarter of 2011 to 10.7m units, slightly ahead of the annual forecast of 10.6m units. Retail transactions are the most accurate measurement of true underlying consumer demand for new vehicles, the analyst said.

“Retail sales in March are exhibiting strength and remain in line with expectations, despite increasing gas prices and falling inventory levels,” said JDP chief forecaster Jeff Schuster. “In fact, retail sales in March may be benefitting from the uncertainty around inventory levels, as consumers flock to dealerships to secure their choice of vehicle as availability decreases.”

Shifts in the retail segment mix are becoming evident, as sub-compact cars are expected to be up more than 0.5 percentage points in March to 3.8%, from 3.2% in February. The share of compact cars is also expected to increase – up to 20.4% in March from 17% in February.

Total light vehicle sales for March are expected to come in at 1,205,200 units, which is 9% higher than in March 2010. Fleet sales are expected to decrease to 213,000 units, based on the expectations that Japanese manufacturers will reduce fleet sales and channel that volume to the retail market, due to concerns about inventory shortages. Fleet volume is projected to be 18% of total sales in March.