Some things to take in
Pokemon GO does not document your speed directly. It logs your current location (Point A), and then in 1 minute it logs your new location (Point B). It then draws a straight line/"crow's flight" between Point A and Point B and calculates the distance. If this distance is 175 meters or less, you get full credit for the distance you traveled.
Because the game only calculates distance in a straight line, the max speed of 10.5 km/h can and should increase the curvier your route is. Here is a crappy diagram to explain what I mean. And no I won't be calculating your specific route for you.
Although the server updates your location data every minute. It will only update your egg screen every 4 minutes. So if you stay at exactly 10.5 km/h in a straight line for 4 minutes, you should see a total of .7 added to your egg when the screen updates.
Before anyone state that they were traveling at -insert speed higher than 10.5- km/h and received partial credit here is why. The location update may not start right when you start moving. It is a completely different timer that is linked to the server. Therefore you may have started walking 30 seconds after the minute timer started and although you were moving at 15 km/h you would have walked 125 meters in the remaining 30 seconds. Since this is less than 175 meters you will receive credit for distance traveled. Once the second minute interval starts you will then travel 250 meters in the full minute and will therefore not get any credit for distance traveled for that interval.