WASHINGTON — The federal government will contribute $474 million in discretionary grants to transportation projects in 37 states, with a heavy emphasis on projects in rural areas, the Department of Transportation said on Thursday, Sept. 4.

The 52 projects will be funded under the Transportation Investment Generating Economic Recovery, or TIGER, program, said U.S. Transportation Secretary Anthony Foxx.

TIGER grants are among the only federal funding sources for large, multi-modal projects that often are not suitable for other federal funding.

The funds are meant to piggyback on money from other sources, including private sector partners, states, local governments, metropolitan planning organizations and transit agencies.

The 2013 TIGER round will support $1.8 billion in overall project investments, the Department said in a statement.