From the article:

Right now, Tesla Roadster owners can charge their batteries for free along California's Highway 101. Five charging stations between San Francisco and Los Angeles have been installed by SolarCity. Though they are currently only compatible with Roadsters, universal plugs are on their way in the next few months, making Highway 101 an electric highway.

The charging stations are located at Rabobank parking lots in Salinas, Atascadero, Santa Maria and Goleta, and one station is located in a parking garage in San Luis Obispo. The Santa Maria station is powered by a 30 kW solar array, while the rest are grid-powered.

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