One indicator is that horseback riding today is one of the most dangerous things you can do. The injury rate for recreational riding is higher than American football, car racing, and skiing. https://tsaco.bmj.com/content/6/1/e000728

I would venture to guess that since stop signs, lane markings and traffic signals were all deployed after cars started killing people, there were a significant number of people annually run over by horse-drawn vehicles, thrown from horseback, or run over by pre-car vehicles like trolleys and trains. Urban streets looked something like this: https://www.wisconsinhistory.org/Records/Image/IM24987