In a pilot now being conducted in San Francisco, the U.S. Postal Service is experimenting with a same-day delivery service of e-commerce packages. The project, called “Metro Post,” will begin on or about Dec. 12 in San Francisco and run for the next 12 months, according to John Friess, a public relations representative for the postal service.

If all goes well, the Post Office has selected more than two dozen cities that are large, densely populated metro areas that could support the Metro Post business model, according to Friess.