Hoboken, N.J., is a 1-square-mile city tightly packed with row houses. It's home to more than 40,000 residents, and parking is one of the city's major challenges.

To alleviate the problem, the Hoboken Parking Authority and a contractor named Robotic Parking created the Hoboken Garden Street Garage Automated Parking System. The garage, which opened in October 2002, is the first of its kind in the United States. The structure sits atop a 100-square-foot lot and stands 56 feet high. According to the National Parking Association, a surface lot of that size could accommodate 25 to 30 automobiles. A conventional, four-story garage can hold anywhere from 80 to 100 vehicles. The Robotic Parking system holds 312.

The parking process begins when a vehicle approaches the facility. A sensor inside the garage is activated by an Automated Vehicle Identification card, similar to an E-ZPass or Fast Lane tag, and a green light flashes above an open bay. The bay door opens, signaling the driver to enter, and once inside, to follow simple positioning instructions on a marquee in the bay. Once the car is properly positioned, the driver takes the keys, slides an ID card to signal departure (which then prompts a number and bay assignment) and leaves.

From there, the driver goes off, and the car...well, the car goes up. When the vehicle first pulls into the garage, it's positioned on a steel pallet. Once the driver leaves, a computer-operated carrier retracts the pallet inward and turns it 180 degrees so the car is facing outward when the driver returns to retrieve it. An elevator then lifts the pallet to an upper level, where it's shifted onto another carrier and moved laterally to an open bay. When the driver returns and slides the card again, the process is reversed, and the car is delivered within minutes.

Darius Sollohub, a New Jersey Institute of Technology assistant professor who studies parking and urban land use, says automated garages are particularly useful in dense city areas. "The greatest advantage of these garages is the space saving," he says, "and the Garden Street Garage is a perfect example."