Originally Posted by
on the path
The difference is that time stopped is recovery time. And how long one stops for can make a huge difference. Are you stopped for 30 seconds or 30 minutes? Useless, I say..
Time stopped at traffic lights might be recovery time, but it also takes some time to get back to cruising speed, and that acceleration uses up more energy than just riding without having to stop for the light.
Average speed is really only useful when comparing rides on the same route, and with similar weather. Even then it's not completely accurate.