The "Cash for Clunkers" legislation, which provides the owner of an unwanted gas guzzler with a rebate of between $3,500 and $4,500 on a new car, depending on the improvement in gas mileage over their old vehicle, probably won't be implemented until September.

Some scrap processors that operate shredders see it as a positive for their recycling business, and steelmakers will benefit from increased demand for steel to make new vehicles and the abundance of shredded scrap when the clunkers are ripped apart. Similar laws have provided a stimulus to automakers in Germany and elsewhere in Europe and are seen as a market-driven way to reduce air pollution and greenhouse gas emissions.

The "Cash for Clunkers" law appeals to my selfish motives. I drive a 1998 Ford Mustang, and while the mileage is low—less than 85,000—it is more than 10 years old.

Today, many of us have come to expect more years of service and mileage from our cars. It is not unusual to see used car ads offering a Honda Accord or a Toyota...