Parking Structures and Heavy EVs

"The Charles Pankow Foundation has funded a study to assess parking garage safety in light of the heavier weight of electric vehicles compared to traditional cars. Led by researchers from the University of Colorado and University of Massachusetts, the investigation will evaluate whether current design standards for garage live loads, set at 40 pounds per square foot, remain sufficient."

A standard US parking stall measures 18x8.5 ft or 153 ft2. The standard parking stall area times the 40 lb/ft2 weight standard yields a maximum of 6,120 lb or 2776 kg.

A large US parking stall measures 20x9 ft or 180 ft2. The large  parking stall area times the 40 lb/ft2 weight standard yields a maximum of 7,200 lb or 3266 kg.

The largest light duty EV sold on the US is the Hummer EV by General Motors. It weighs 9,640 lb. Clearly, many of them parked in the same parking deck of a parking structure will pose a problem.

However, the rest of the EVs on sale, as of end of 2023, as shown in the table below (click image for better viewing), would be no problem for any parking structure with all standard parking stalls. All EVs in production except for one Mercedes SUV (and the Hummer EV) weigh 2720 kg or less, which is below the design live weight for standard stalls, 2776 kg.

A compact US parking stall may be problematic. A compact US parking stall measures 16x8 ft or 128 ft2, times the 40 lb/ft2 weight standard yields a maximum of 5,120 lb or 2323 kg. Several popular EV in the US exceed this weight (see table above), but most of them would barely fit into a compact parking stall.

A quick preliminary recommendation could be that EV should not be allowed to park in compact stalls.

In reality, the overall risk is very small because (1) the load bearing design of parking structures includes all corridors and driveways for vehicles to enter, exit and maneuver, (2) the portion of EV in the traffic mix is low, about 10% on the average, but higher proportions exist in specific locales.

On the other hand, aging and compromised structures, and all those that may not have been designed with the current US standard for live load may be susceptible to overloading. A 2023 parking structure collapse in New York City set all this in motion.