I don't have a driver's license, and I doubt I'll ever be able to get one due to my Asperger's. I'm currently on the hunt for a job, and during the about 2 years in total (including previous job hunt periods), I've had about a half-dozen times that I've been late to a job interview because of extenuating circumstances (usually missing my transfer due to a bus or a train being late). Most times, it was less than 5 minutes, but I had one time on a snowy day where the trains were heavily disrupted causing me to be over an hour late, and recently, I was 15 minutes late. Both of these longer times, I have informed my contact at the company as soon as I knew I would be late and gave them an estimated time of arrival.
I've also had some cases where I arrived 10 minutes or more early to an interview, usually because the time tables were such that those were the only time I could arrive without risking being late. One time, I arrived half an hour early, even though I took my bike, due to a combination of taking some room for error and a route that was unexpectedly mostly downhill, skewing the Google Maps prediction.
Usually, when this happens, the interviewer is understanding, especially when I inform them in time. However, being late can't possibly be helping my chances, and I doubt that being excessively early is all that positive either.
How much does being late or early to a job interview affect my chances?