How fast did the first car go when it was invented?

The speed of the first cars varied greatly depending on the design and the year. There wasn't a single "first car" and early automobiles were quite different from what we think of as cars today. Some of the earliest experimental vehicles, like those built by Karl Benz in the late 1880s, likely only reached speeds of a few miles per hour (a brisk walking pace). As technology improved over the next few years, speeds gradually increased. So there's no single definitive answer.