Urban Planning and Design

How ‘shared parking’ can improve city life

More efficient parking systems mean less congestion, fewer emissions, and lower rents.

By Willa Ng

Photo of parking lots and city buildings

Tony Webster / Flickr

We see pictures like the one above all the time: a huge parking lot, often half-empty, in the heart of a city. Yet we also hear about fuming drivers circling endlessly for a parking space. How can both be true at the same time? How can there be way too much parking and never a spot when you need one?

It's the visceral reaction to this frustration that makes cities build more parking than necessary. In fact, most cities require developers to create a minimum amount of spaces, regardless of actual demand. One recent study of 27 mixed-use areas across the U.S. found that parking was oversupplied by an average of 65 percent. That was true even in places where people responded that there was never enough.

There are good reasons for that perception. That huge empty parking lot? It's not open to you! It's reserved for the employees of that office building, even though they're only there Monday to Friday, 8 a.m. to 5 p.m. That empty parking garage next to the hottest restaurant in town? It's only open to church patrons who come on Sundays.

Why do developments and establishments hoard parking? One reason is it's preferable to keep a parking space empty most of the time than to risk angry responses when people can't get to the parking space they were "guaranteed." You'll see this all over a metro area --- from residential and office buildings to big box stores and local parking lots. And even when operators are open to having their parking space "multi-task," they still face the challenge of setting up a system to receive, advertise to, and collect revenue from different types of parkers.

So what can cities do about it? Well, one approach to solving urban America's parking problem is called "shared parking." If there's a movie theater right next to an office, for instance, the theater can use some of the spaces at night that get used by office workers during the day, rather than building its own.

It's a pretty simple idea, but the execution is where things get tricky.

The biggest hurdle to shared parking is uncertainty and lack of information. Drivers may ask: Am I allowed to park here? Am I going to be charged an arm and a leg for this space? How do I know where these spaces are? How do I get in? What if I can't get my car out? Parking operators have questions of their own: How can I be sure there are enough spaces for my priority users? How do I get paid? Is the revenue worth the cost of keeping my facility open?

Technology gives us new ways to think about addressing these questions. Many parking lots already have entry/exit counters. If we combine those with aggregated, anonymized location data from smartphones, we can get a pretty good idea of when and where parking spaces are available, without requiring operators to install new equipment.

This information can be collected and crunched to determine which parking spaces should come "online" at different times of day, stitching together a network of available supply from the previously fragmented spaces. Wayfinding apps and in-car navigation systems can guide drivers to those spaces and offer them a secure way to pay.

Suddenly it's possible to imagine a cluster of previously hidden off-street lots in mid-density cities becoming easily accessible to a much wider population.

That's the type of coordination Sidewalk's Flow team has started to think about as we talk with DOT Smart City Challenge finalists (and other cities) about their parking needs. What you'd get when you connect drivers and spots in this manner is better utilization of existing assets --- something like a sharing economy for parking. If cities and technology can show that shared parking is feasible and reliable, and that it provides a better parking experience, the implications are immense.

Here are just a few:

  • Planners and local officials could eliminate static parking minimums and adjust zoning to promote mixed-use developments more conducive to sharing.
  • Developers could build fewer parking spaces (something they want to do anyway) in favor of more living, office, or retail space that people actually use --- and they could stop bundling the cost of parking into rents.
  • Less street space would be dedicated to blank parking garage walls and vast stretches of asphalt in favor of a more walkable environment.
  • Drivers would get to their parking spaces as efficiently as possible, which means less congestion and fewer emissions for everyone.

The technology to track demand, provide communication, and coordinate payment isn't the only hurdle for shared parking. But it's a start. If cities and parking operators can run an efficient, shared pool of parking spaces that guarantee safe and convenient service, we can all start to understand how much parking we really need. When we understand the minimum amount of parking we need, we can make better decisions about the best use of our valuable land.

And maybe that big empty parking lot downtown will become a thing of the past.