The legislation, from Rep. Richard Hanna (R-N.Y.), would cap government buying and leasing to 80 percent of the amount of money spent in 2010. According to the General Services Administration (GSA), the government bought 63,794 cars and trucks in 2010, and spent about $1.5 billion to get them.

That means purchases alone would be cut to $1.2 billion each year under the bill, and that the government spending would be cut by about $1.2 billion over four years compared to the pace set in 2010.

The cut also implies that government could only buy about 51,000 cars per year under the bill, which would be the lowest annual amount in more than a decade. In 2011, the government bought 54,000 cars and trucks, but bought 86,500 in 2009, and about 70,000 in 2008.

According to GSA, the government owned 662,000 vehicles worldwide, up from 651,000 in 2009, and spent about $1.2 billion in fuel costs in 2010.

Republicans are calling up the bill under a suspension of House rules, which means a two-thirds vote will be required for passage. Democratic opposition could prevent passage — Republicans will need several dozen Democrats to support it to have it pass.