After decades of telling residential developers to build a minimum amount of parking for tenants, smart cities are now looking for ways to discourage the creation of unnecessary spaces. That’s because while some people enjoy the amenity of a personal spot, residential parking also makes housing less affordable (by jacking up rents to defray the cost of building a garage or a lot) and makes traffic more awful (by encouraging commuters to drive to work). It's a small win for a large loss.

Seattle is among the U.S. metros working hard to change the situation. Years ago it eliminated a rule requiring developers to build parking for new buildings located in downtown or transit-friendly areas. That policy has produced mixed returns; some housing developments provide no parking for tenants, while some still build nearly a spot per person, leading to just over half a space per unit, on average:

A new idea, presented recently to the city council, would take that parking policy a step further by requiring developers to offer new tenants a suite of alternative transport options. So instead of getting a parking spot, a resident might get a transit pass or a bike-share membership instead—a trade that, over time, should reduce parking demand and promote car-free living. Here's the basic gist of the proposed "residential transportation options program," via the city's planning department:

Require bus passes for new residential developments in center city neighborhoods and other areas frequently served by transit, along with car share memberships, bike share memberships, or similar services.