San Diego is one of five cities in the nation testing some new vehicles.
The scooters are quick, clean and green, according to officials. The San Diego Post Office unveiled the two fully electric delivery T-3 motion scooters in Wednesday. Mail carriers can zip along crowded streets at speeds up to 12 miles per hour.
The T3 battery-operated three-wheel stand-up vehicle can be driven inside or outdoors, and travels about 40 miles on a charge.
"They bring it back at night and recharge the battery," Postal Service spokesperson Mike Cannon said. "It costs less than 4 cents a mile to use these vehicles. They don't pollute -- they are all electric."
The T-3s come with or without a trailer to store mail and can carry up to 450 pounds.