Benz developed a successful gasoline-powered two-stroke piston engine in 1873. In 1886 he used one of his engines to create the Benz Patent Motorwagen. [TheEngineeringPage]
(new window) Note the bicycle is easily keeping in front of the car. The comments indicate the top speed is 10 mph.
These videos provide insight as to why the safety bicycle was so popular at the end of the 19th century. A bicycle was a lot less cranky and had as much protection from the elements as this car does.