The price of free parking keeps going up. One cost is painful urban congestion, which is made worse bydrastically under-priced street parking. Another is a relative cost to the environment, which occurs when the near-certain prospect of free (or cheap) parking entices people into their cars and away from alternative forms of transportation. Recently a team of researchers from the University of California at Berkeley, writing in a recent issue of Environmental Research Letters, described a previously unknown cost — energy and…