Older people need rides, but what’s stopping them from using Uber and Lyft?

Martin Gerstell treasures his Thursday morning volunteer stint at the National Gallery of Art, where he fields questions at the main information desk. He patiently responds when visitors ask about the current exhibits, whether the paintings are real, where the bathrooms are.

Usually, fellow volunteers give him a ride from his assisted living residence in northwest Washington to the museum downtown, and home again. But when they can’t, Mr. Gerstell, 94, uses the Uber app his granddaughter installed on his iPhone.

“They appear very quickly, and they’re very helpful,” Mr. Gerstell said of his Uber drivers, who fold and stash his walker in the trunk. Summoning a taxi, his previous option, usually took 15 to 20 minutes; Uber arrives in three to five minutes and charges less, under $20, to drive him downtown.