The average price of new cars increased in May 2011, by 0.167% or £47 from £28,159 to £28,206.
According to the Driven Data index, it is the fourth time prices have increased this year with a 2.208% rise in January, 0.210% rise in February and 0.103% rise in March.
The underlying pace of inflation in car price has risen over the past 12 months to 4.938%. It rose by 4.302% between May 2009 and May 2010.
The Driven Data index is calculated from the retail prices of every car model currently sold in the UK.