Is a dog faster than a human riding a bike?

It really depends on the person and the breed. Some marathon runners will be able to run farther than most dogs, but most sport breeds like a schutzhund trained German shepherd will run all but the best of human athletes into the ground, but at the same time most fit people will be able to handily outrun a toy breed.

On the whole though, given the average medium or large sized dog will be able to outrun the average person.

Yours is a very vague question.