Looking for That Elusive Parking Spot? Look No Further Than Your Smartphone

 This fall, San Francisco will test 6,000 of its 24,000 metered parking spaces in the nation’s most ambitious trial of a wireless sensor network that will announce which of the spaces are free at any moment.Drivers will be alerted to empty parking places either by displays on street signs, or by looking at maps on screens of their smartphones. They may even be able to pay for parking by cellphone, and add to the parking meter from their phones without returning to the car. Read On.