Electric and Autonomous Vehicles Changing the Parking Landscape

From the Summer 2022 issue of
Ascent Magazine.

by Monica Schultes

New vehicle technology is going to drive the future of parking.

Electric vehicles (EVs) are expected to account for more than 11% of new sales in the United States by 2025. As these new vehicles hit the streets, the EV charging infrastructure is struggling to keep pace. Several cities and states are adopting building codes that require EV charging infrastructure. This is typically a percentage of spaces in the parking structure for EV-capable spaces (for the future installation of EV charging equipment) or EV-ready spaces.

EV charging access in parking structures is increasing in areas of the country experiencing greater adoption of electric vehicles. California’s most recent regulation for EV charging support requires that all new, nonresidential construction projects provide the infrastructure for a minimum of 10% of the total required parking spaces. New hotels require infrastructure for 6% EV spaces, multifamily housing must provide for 10%, and all new single-family and duplex residences must ensure a dedicated branch circuit and cabinet are installed.

This emphasis on EV readiness is due to the relatively low cost of EV infrastructure as a percentage of new construction, compared with post-construction or retrofit. Precast concrete parking structures can readily integrate the electrical conduits in a topping slab. They can also support solar photovoltaic arrays on roofs to cover the increased energy demand of charging stations.

EVs are already creating change. Chris Gradziel of Walker Consultants sees varying requirements across the country. In some locations, up to 25% of parking spaces must be EV-equipped. This is quite a difference from a current parking structure, which uses a small percentage of energy compared with the building it supports, to one that has a much larger electrical load. If EV batteries continue to evolve and improve, however, they will have a longer range than gas vehicles. Under those circumstances, fewer EV chargers will be needed than some local ordinances are requiring for nonresidential parking structures, according to Gradziel.

Autonomous Vehicles

There is much uncertainty as to when autonomous vehicles (AVs) will become common and how widespread their impact will be on our mobility. As self-driving cars become a reality, parking structures will need to evolve. AVs will still wait in a parking structure, but driverless parking is more exact than human driving and does not require doors to open. So less square footage will be required per car. Based on typical car dimensions, a structure would have the capacity to hold five AVs for every four traditional spaces. There might be even more efficient means of stacking and storing them.

A future AV parking structure would require more extensive passenger loading and unloading areas near entrances. “AVs and EVs will refocus site planning on pedestrian experiences by utilizing new techniques. These new vehicles will have to ‘live’ somewhere, so I don’t see parking structures disappearing,” says Ginger Thompson, Dreyfuss + Blackford Architecture. Thompson believes the University of California Davis Medical Campus is already geared toward the future. Their concept of remote parking structures that encourage alternative means of transportation is forward-thinking. They have incentives for bikes, public transit, and a mobility hub for electric buses from other campuses. At the same time, she says, “we need to store some sort of vehicle when not in use, so we intentionally designed the garage to be able to reconfigure it.”

Self-Park to Auto-Park

Today’s self-park precast concrete structures can handle the additional load from tightly packed vehicles. But in future designs, the current bay spacing and layout may change, which would impact double-tee spans, column grids, and concrete thickness. The interim step toward AVs would be stacked vehicles or additional densification, similar to valet parking. Until a large percentage of the population endorses self-driving cars, we are years away from drastically changing the current system, says Clark Pacific’s Steve Voss.

Fire Concerns

As the demand for electric vehicles (EVs) increases, parking structure design will have to address the possibility of EV fires. David Rich, vice president and project development director for Rich & Associates, says that some jurisdictions in Europe do not allow EVs in parking structures, yet most jurisdictions in the United States are not required to include active fire-suppression systems in open air parking structures. “We expect fire codes will change in the near future to address this issue,” he says.

Many clients ask Rich for some level of EV charging capacity in the initial design, as well as infrastructure for future charging
stations. “For example, we’re doing a garage for an automotive company in the Detroit area that is designed to support 100% of future EV charging capacity, which is 1250 cars,” Rich says. As a rule of thumb, Rich recommends allotting 5% of the total
number of parking spaces for electric vehicles, with room to add more charging stations as needed. Rich anticipates more demand in the future for autonomous vehicles (AVs) as well. He says one benefit of using precast concrete is that column-free, long-span designs support parking cars closer together. The consulting firm has designed standard precast concrete parking structures for valet operation and found that the density of the parked cars “is similar to what we expect for AVs.”

“We don’t have any concerns about the structural load that AVs would add,” Rich continues. “But we do have clients who are
interested in taking advantage of this evolution of driving, and how they can maximize their revenues by parking more cars in the same footprint.”