Where I grew up (Oklahoma City, OK), people used cars to get everywhere. The roads have multiple lanes to cut down on traffic and there are lots and lots of highways. I was shocked when I got to Rome to find that transportation here is very different than with what I grew up.
In Rome, there are three primary modes of transportatin: car, tram and motor scooters. The cars that Romans use tend to be small, compact models. Trams are like trains that run on set tracks through the city throughout the day. Motor scooters are similar to motorcycles.
I have not traveled in a car or on a motor scooter here because my program doesn't allow it. However, I have ridden the tram. During peak hours (8-10 a.m., 12-2 p.m., 5-7 p.m., 9-10 p.m.), the trams can get crazy crowded! Sometimes there are so many people, I just walk instead. At first, taking the tram alone scared me, but once I got used to it, it became very convinient.
All three of these modes of transportation are reflective of Roman people and the city itself. The streets in Rome are narrow because the city is really, really old. Many of the buildings are older than the invention of cars! Think about it.