Faced with a weakening economy, more companies are targeting travel and entertainment expenses USA Today reports.

Rental car companies are vulnerable to belt-tightening, even though contract rates are expected to climb by only about 2 percent this year, says Neil Abrams, president of industry tracker Abrams Consulting.

Companies are increasingly telling travelers to hire smaller cars or that they won't reimburse them for “bells and whistles,” such as navigation systems, he says.

They're also targeting unnecessary costs, such as the refueling bill when a car is returned with an empty tank. Car rental agencies charge as much as about $7 a gallon, which for a 20-gallon tank and thousands of rentals a year adds up.

Penny-pinching strategies vary. United Rentals, a publicly traded company based in Greenwich, Conn., with 11,000 employees, requires some travelers to obtain supervisors' approval before booking, says Megan Adams, United's purchasing chief. The new rule, implemented in January, will cut about 20 percent of their trips, she says.

According to USA Today, new travel policies and stricter enforcement will cause the average U.S. hotel occupancy rate to fall slightly to 62.6 percent this year vs. 63.2 percent in 2007, says Bjorn Hanson, chief lodging consultant for PricewaterhouseCoopers.