Now that plug-in electric-vehicle technology is ready for prime time, forward-looking cities are trying to modernize their building codes to stay current.

The National Renewable Energy Laboratory yesterday published case studies of four locations that have crafted plans to encourage drivers to go electric. Rather than financial or technical hurdles, the biggest priority of these cities is updating the permitting process around home and public charging stations.

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Although it's not necessary, most plug-in electric-car owners are expected to have a dedicated charge port installed at their homes, which will work at 240 volts and cut charge time roughly in half.

One of the concerns automakers and potential buyers have is long delays in getting these chargers installed since building codes don't always explicitly address them.

In an effort to avoid delays in installations, Oregon last year adjusted its building codes to clarify the situation for electricians. Home charging stations now fall under the same building codes as large appliances, such as electric water heaters. Only one in ten of an electrician's installations needs to be inspected, another streamlining effort.

Raleigh, N.C., too, applied an existing permitting and inspection process to electric-vehicle charging stations, or electric-vehicle supply equipment (EVSE). The area expects that the entire process takes a few days, rather than several weeks, and it intends to allow electricians to apply for permits online as more people are trained. Houston, meanwhile, claims that it has its permitting and inspection process down to one day. The other location included in the study is Los Angeles.

Electric-vehicle experts advocate building up the charging infrastructure for plug-ins in specific regions to give plug-in hybrid and all-electric vehicles a foothold in the auto fleet.

The case studies are designed to be blueprints for municipalities, said Linda Bluestein, the co-director of Clean Cities, a Department of Energy-funded program to reduce oil consumption in transportation. "Preparation by municipalities, utilities, states and regions will determine how quickly and smoothly that transformation takes place," she said in a statement.