Electric cars, compared to cars with internal-combustion engines, are nearly silent, which can present a danger to cyclists and pedestrians. So car companies are turning to sound engineers to craft artificial soundtracks for things like backing up, or starting the engine. John Seabrook, who writes often about music, reported on the composers and designers who are building a new soundscape for the streets and highways of America. Plus, a visit with Ada Limón, who was recently named the twenty-fourth U.S. Poet Laureate. Limón lives in Kentucky, and in 2018 she took the Radio Hour to her favorite racetrack, and spoke about her lifelong love of horses.