http://www.mapmytracks.com/ en Copyright 2008 2008-12-04 http://www.mapmytracks.com/explore/track/motorway-driving/354 You really did 153 mph? 2008-01-24 {screen_name} http://www.mapmytracks.com/explore/track/motorway-driving/354 Currently, speed is calculated between each individual point. Due to the inaccuracies that can be introduced by rouge GPS locations, this can lead to rather optimistic top speeds! We are working to fix this by basing speed on a sampled average of GPS positions, which should be in place soon. 2008-01-24 {screen_name} http://www.mapmytracks.com/explore/track/motorway-driving/354 I see, thanks. I thought these inaccuracies are only a problem at slow speeds, like running or maybe cycling. Probably car navigation systems use some averaging too because they show pretty stable speed values. 2008-01-25 {screen_name} http://www.mapmytracks.com/explore/track/motorway-driving/354 Yes, the satnav in my car is very accurate. It is possible to get the speed directly from the data which a Bluetooth GPS receiver outputs, which may be what the satnav is doing with it’s embedded GPS. Unfortunately, mobile phones with internal GPS (like the Nokia N95) do not support this. A universal solution which works for all mobile phones therefore has to calculate it itself. 2008-01-25 {screen_name} http://www.mapmytracks.com/explore/track/motorway-driving/354 Have a look at the top speed now. We have altered the way that it is calculated to smooth over any rogue points. You may need to clear your cache to get the revised figures. 2008-01-25 {screen_name} http://www.mapmytracks.com/explore/track/motorway-driving/354 I can see. Good improvement! 2008-01-25 {screen_name}