Detroit
As in other major American cities in the postwar era, construction of an extensive highway and freeway system around Detroit and pent-up demand for new housing stimulated suburbanization; highways made commuting by car easier. In 1956, Detroit's last heavily used electric streetcar line along the length of Woodward Avenue was removed and replaced with gas-powered buses. It was the last line of what had once been a 534-mile network of electric streetcars. In 1941 at peak times, a streetcar ran on Woodward Avenue every 60 seconds.

Q: In which year was the last electric streetcar line removed?
1956