RFID Is Key to Car Clubs' Success

By Mary Catherine O'Connor

Jan. 7, 2008—With gas prices and consumers' motivation to lessen their impact on the environment both rising, the growth of car-sharing programs is booming. Currently, approximately 348,000 individuals in 600 cities in 18 countries worldwide share nearly 11,700 vehicles as part of organized car-sharing services, according to a 2007 study by the Transportation Sustainability Research Center at the University of California, Berkeley. And nearly all of those car-sharing drivers carry an RFID card or key fob to access the cars they use. "RFID cards are the predominant means for accessing car-sharing vehicles," says Susan Shaheen, research director at the center and coauthor of the study.

Members of car-sharing programs use online schedulers to reserve cars, which are parked at set locations throughout a particular city or town. Most clubs charge hourly rates, along with a small fee per mile. The clubs offer fleets of fuel-efficient models, and many feature hybrid or electric cars. To make it easy for members to borrow any car within a fleet, the clubs send them RFID cards or key fobs when they join.

To unlock a reserved car, a City CarShare member holds an RFID-enabled key fob up to an interrogator mounted on the dashboard.

To open the door of a reserved car, a member holds the RFID card or fob up to a small dashboard-mounted computer containing an RFID reader. The interrogator collects the member's ID, encoded to the RFID tag inside the card or fob, by reading it through the car's windshield. The computer then transmits the number, via a cellular phone network, to a reservations system on a server maintained by the car-sharing company. If the system shows that the member has reserved that car, the computer unlocks the doors.

Most car-sharing clubs ask drivers to leave the keys in a designated place within the car. The keys can be left inside because the computer also controls an ignition-system lock. When the driver exits the car and uses the RFID tag to lock its doors, the ignition system becomes disabled as well. Thus, even if a thief were to force his way into a locked vehicle, he could not start it with the key inside. When the doors are unlocked with the RFID tag, so is the ignition. Some clubs request that members store the key inside the car's glove compartment, which automatically locks and which can be opened only by entering a personal ID number into a keypad inside the car.

WhizzGo, a U.K.-based car-share provider, turned to German firm Invers to establish its car-access system in 2004. Invers is the largest provider of RFID-based car-access systems used by car-sharing companies, according to Dave Brook, a car-sharing consultant based in Portland, Ore., and author of the Carsharing.US blog. The company embeds a passive 125 kHz Hitag RFID inlay, manufactured by NXP Semiconductors, in each card. The inlay is interrogated by the Invers dashboard-mounted computer, which also controls a lock on the glove box, where WhizzGo drivers secure the car keys. The ignition system is linked with the glove compartment's lock, and the car cannot be started unless the compartment has been properly opened.

The Invers computer powers a GSM-based SIM card in the computer, enabling it to exchange data with WhizzGo's servers. It also has a keyboard that lets WhizzGo drivers send text messages to the company's reservations personnel. Charlotte Morton, WhizzGo's managing director, says drivers often use this feature to request an extension of their allotted time with the car.

City CarShare, a nonprofit car-sharing organization founded in 2001, was the only such service operating in the San Francisco Bay area until 2006, when two large for-profit car-sharing companies, Flexcar and Zipcar, entered the market. Once City CarShare began its operations, it couldn't find an easy-to-deploy, off-the-shelf car reservations and RFID card-based car-access system, so it created its own, says Brian Kusler, who at the time was a principal at City CarShare.