Looks like this was posted too soon.
Benz had the first patent and serves as a milestone for historys, but turns out it wasn't the first automobile, and certainly not the first powerplant-vehicle. There were trains, mining cars and the like already in use, and in all likelyhood there probably was a few barn projects that also made it to the road.
The De Dion Bouton was made a few years earlier.
De Dion, Bouton et Trepardou Dos-a-Dos - Supercars.net
"Boasting a top speed of 38 miles per hour, the De Dion Bouton's twin tandem compound steam engines use coal and water for fuel. On April 28, 1887 it won the world's first auto race, from Paris to Neuilly and back, covering a distance of 19 miles while averaging 26 miles per hour."
Back then, the early steam cars were by far the fastest on the road, but could take up to 45 minutes to warm up and drive.
With the complexity of starting and keeping the gasoline engine going, the horse-and-buggy stayed in use for quite a while, and was considered a vehicle for men only.
There were electric vehicles in widespead use back then as well, and I think it was Dodge who marketed their cars as "easy enough for women and children to drive". The range still seem to be the limiting factor for their use.
The ability to easily "get in and go fast" was the limiting factor to the spread of the automobile until the ignition switch, the electric starter, and the spark plug came along.