There are not too many statistics about hitchhiking. Most hitchhikers don't (bother to) keep track of the specific details. Fortunately some did, and it would be great to extract some significant information from this.
- The waiting time per country
- The percentage of number plates from other countries (e.g. in SK: 90% SK, 5% CZ, 4% H)
- The average distance per ride.
It would be good if all the following data were available under a free license. Creative Commons Attribution would probably be the most sensible.