The National Highway Traffic Safety Administration says dealers and consumers do not need to pre-register for the program, which provides $3,500 to $4,500 to people who trade in gas-guzzling cars and trucks for a new, more fuel-efficient vehicle.
The voucher program aims to generate about 1 million new auto sales, while also increasing fuel-efficiency of the overall fleet of cars on American roads.
Traffic safety spokesman Rae Tyson says the government has an official site for the program at www.cars.gov.
Tyson says some Web sites have offered pre-approval sections that request a consumer's Social Security number and other personal information.
The traffic safety administration has given information about these unofficial sites to the Justice Department's Internet Fraud division.
The program will run from July 1 to November 1.
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