Home Depot

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shoppers may soon be able to fill up their gas tanks and buy some snacks at convenience stores outside the big-box retail outlets.

The leading home-improvement retailer plans to test a new convenience-store format, including gas stations and car washes, at four Nashville Home Depots this December.

"The convenience-store industry is a $268 billion market," Home Depot said in a statement. "We see great potential in adding to our top line growth while also driving incremental traffic to our retail stores."

Along with gasoline, the convenience stores will sell typical gas station items like chips, soda, beer and other groceries. Two of the stores will have car washes.

"Depending on the success of this pilot project, we will make a decision about whether to expand this format to other stores," said Home Depot spokeswoman Paula Smith. "It's too early to speculate about that now."

She said the convenience stores could be especially effective with contractors who visit Home Depot in the morning to get supplies for a day's work.

"Now, they'll be able to get everything they need for the job site from lumber and tools to breakfast and lunch," Smith said. "They'll be able to keep their whole crew at the site all day, because time is money for them."

Also, since Home Depot stores are often located in high-traffic shopping areas, Smith said the convenience stores could win new customers for the company.

Other general merchandisers, like

Wal-Mart

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and

Costco

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, have added gas stations outside their big-box stores with some success.