Can you go 500 kilometers in 8 hours without driving faster than 55mph

Yes indeed! You sure can. This is your lucky day.

500 kilometers is about 310.7 miles.

In order for you to cover that distance in 8 hours, you only need to average

about 38.8 mph. If you stop along the way ... for food, gas, rest, pits, etc ...

then you'll have to drive a little faster to keep up your average. But by managing

your stops, you can certainly do it without ever exceeding 55 mph.

Yes. 55mph equals 88.5139 kmph. in 8 hours, you will have traveled slightly over 700 kilometers.