What public transport used roads (not streets) in the early twentieth century of the US, when much if them were built? According to [1], by 1929 the private car

What public transport used roads (not streets) in the early twentieth century of the US, when much if them were built? According to [1], by 1929 the private car was doing 175 billion passenger miles, while the bus was doing just 7. As they write, "Although intercity bus travel climbed from nothing to over seven billion passenger miles in 1929, it was always the choice of a relatively small number of people." And of course, trains don't use roads. What other public transport is there? [1] https://eh.net/encyclopedia/the-bus-industry-in-the-united-states/ https://eh.net/encyclopedia/the-bus-industry-in-the-united-s...