Public charging spots will happen if/when popularity of electric cars takes off. It already has happened in some places, for example Oxford in the UK - http://www.oxfordjournal.co.uk/news/travel/2699-city-gets-mo... (I believe there's at least a few more since that article was written, could be wrong). Due to not having the same requirements as petrol stations (namely being able to store huge amounts of flammable liquid), there's no reason for them to be located there, hence their being in car parks in Oxford.