Five Alternatives to Giant Parking Plinths

Last year, I sketched out why downtown has so many huge parking plinths. But another world is possible! Today, we’ll check out alternatives to the plinth. Then, coming soon, we’ll have a look at how regulations could finally #parktheplinth.

The Independent (aka the Jenga Tower) under construction. The open floors are parking, the one with windows above are where the residences start. Photo by Dan Keshet.

Transportation Demand Management

The easiest car to park is the one that isn’t driven to the destination at all. TDM programs work with tenants to find ways to reduce the number of employees driving cars into work. This could be anything from employer-sponsored transit passes or stipends for employees who don’t bring a car, to secure bike racks and shower facilities to encourage more cycling.

Some programs sit down with employees to help brainstorm alternative ways to get errands done without driving a car into work every day. Not everybody can change their commute patterns overnight, but enough people want to do it that investing some money upfront can have a real impact on the amount of parking needed.

Automated parking

Brockett Davidson, an architect at Rhode Partners in Austin working on 1615 Guadalupe Street, is also working on a residential project on the Riverwalk in downtown San Antonio. The site is extremely constrained, with no room for underground parking because it’s close to the riverwalk and little room for above-ground parking. So he made use of an automated parking system manufactured by PARKPLUS.

In this system, the resident parks their car on a platform which gets carried up to the garage on an elevator. Once on the garage, the platform finds an open parking space by moving around similarly to Amazon’s robot pallets.

Floodgate has a parking plinth, but much smaller than it would be with less efficient parking.
Image: Rhode Partners

Using this system, he’s able to fit twice as many cars into the same space, cutting the number of garage floors in half. With taller floors and the right automated parking solution, it may even be possible to fit four times as many cars into a single garage story. On top of that, the floors he used for parking don’t need ramps, opening up the possibility that they could be reused for other purposes if car parking is no longer needed down the line.


Open Parking

Former Travis County planner Mark Gilbert was determined to cut down the county’s ratio of parking spaces per employee. The way he figured out how to do it was to stop assigning specific parking spaces to specific employees. Not every employee is at work every day so reserving parking spaces means that every day, some percentage of parking spaces would go unused.

To start with, Gilbert converted employee’s designated spaces to open parking permits, allowing the use of any space in the garage. At this point, the ratio of parking permits to spaces was still 1:1. Then over time, he observed the maximum number of spaces used on a given day. When he knew it was less than 100%, he pulled some folks off the waiting list and gave them parking permits, then observed how many spaces were used again.

The process repeated multiple times until spaces started to fill. At the end of the process, different garages had between 20% and 40% more permits than spaces, all without running out of parking on any given day. If every office building downtown that has assigned parking switched to open parking, similar gains might be achieved in those buildings as well.

Mixed Use Parking

When a building or a cluster of buildings have a mix of uses (e.g. apartments, offices, restaurants, shops), sometimes it’s possible to use fewer overall parking spaces by sharing across these different uses. During the middle of the day, more of the parking spaces may be used by office workers than residents, then that ratio is flip-flopped at night.

Meg Merritt, a transportation expert with Nelson Nygaard, made just this case recently while testifying to City Council regarding a large mixed-use development in Southeast Austin. The exact amount of spaces saved can vary depending on conditions, she said, and estimating the savings can be more art than science. But that doesn’t mean the savings are insignificant! Most single-use parking garages go virtually unused at one time of day or another.

Underground Parking

Building parking underground is generally more expensive than building it above-ground, because before you build, you have to dig a giant hole. But beside the aesthetics and relationship with the street, there are other upsides, according to a land developer I spoke with. Above-grade parking needs many different “penetrations” through it to carry elevators and the like to floors above.

Sometimes placing these elevators in ways that work for the upper floors makes them very inconvenient for the garages. For underground parking, you don’t need to use the same elevators as the above-ground floors so you can place just a single elevator bank exactly where you need it, allowing you to park more cars per square foot.

While above-grade parking is limited mostly by how many flights a driver is willing to circle in order to get to their parking space, the restrictions on the number of floors of below-grade parking is much more site-specific, depending on how far down you have to go to hit denser limestone (in Austin; other cities sit on top of different surfaces) or to hit the water table. This means that for a specific site, it may be that going from two to three floors of below-grade parking doesn’t cost much more, but going to a fourth floor costs way, way more.

Up Next

How City Council could fix our zoning regulations to make these alternatives not only possible, but preferable!