My car does a the same journey everyday with a specific start and end journey time. It does the same route everyday. Therefore I know the amount of kilometres the car will cover each day and at what time of the day it will have accomplished its journey. What I would like to do is create a code that updates my car’s total kilometres value at whatever time it finishes its journey.
For example if my car’s journey is 900 km and it finishes its course at 17:00, I would like the code to add 900km to the total kilometres of the car everyday at 17:00.

I was also wondering if I had multiple cars that all finished at various times and did various distances, would I need a separate code for each one?

I am stuck as to where to begin. I have tried various timer/clock codes but I am struggling to see how I could adapt them to my scenario.