it's an amazing tool to measure progress...if you compare it to the same route. Not a similar route, the same route. for example, i have a great loop around where i live that is about 21 miles. starting out this june when i first got my bike, i'd shoot for an hour 20 min. yesterday i rode it in 59 min. progress. mind you i live in southeastern ohio, which isn't flat in the least bit. average speed is something you can use only to compare apples to apples.