When the city of Seattle was working through the 2008 NEC, preparing to adopt it along with their own local changes, they decided to add a requirement related to electric vehicles. I had a chance to listen to part of the debates over this issue. They wanted to require, as a minimum, that certain new buildings (based on occupancy) install a "pathway" that would be reserved for future installation of charging stations. The tricky part was defining what they meant by "pathway," or finding some other words that would convey their intent. I don't have a copy of the final version handy, but what I recall is that they wanted a spot on the wall reserved for the charging panel, and a spare conduit installed from that room back to the electric room.