Average of Measure

Hi all.

First or all, let me tell you that I went through several posts with similar questions but I couldn't solve the issue anyway. So I am seeking for help here. And I am coming back to PowerBI after some months of travelling so I am not at my best shape :smileyhappy:

I am working with data about vehicle trips. Each vehicle only does one trip per day. Each trip might have several stops, hence the multiple start and end times for each vehicle per day.

I want to get info about the average trip time, average stop time, stops per trip, average stops per trip, all of this per vehicle and per day.

I am working with a set of data that looks like this:

First question: is is well processed? Should I use another structure? This structure confuses me to be honest.

So far, I could only work on the trip time. I created this measure: TripLengthHours = DATEDIFF(MIN(Trips[TripStartTime]),MAX(Trips[TripEndTime]),SECOND)/3600

For individual values, it works good, but on a matrix, the Total values obviously go mad:

Second question: what is wrong with the measure or the thinking (probably a lot)?

Third question: could you help me with the remaining values I am looking for?

Thanks a lot in advance.