Slow Speed (purple display) in Tunnels
Posted: Mon Dec 17, 2018 5:42 am
I rode Garda Lake Loop part 4 for the 1st time this morning.
In many of the tunnels (at least 8 times by my rough count) the speedometer display went purple and my speed was shown as about 4 km per hour for long periods of a minute or two (not the odd second). As I came out of the tunnel it went back to the usual display colour with genuine speeds (30-50 km per hour depending on the tunnel). So the effect seemed closely linked to being in the tunnel or not being in the tunnel.
Some of the tunnels were empty of traffic, so its not as if the route needed to be filmed slowly leading to a purple display. I am guessing the problem was something to do with losing the GPS signal in the tunnels so distances and speeds were recorded too small. Supporting this theory, the website has the course length at about 36 km (matching the corresponding website profile). whereas the profile shown in the VeloReality App is 26.8 km so it looks like up to 9 km of the course might be missing - lost in the tunnels due to GPS issues?
My reported average speed (correctly matching distance travelled with time) was quite impacted by the forced stretches at 4 km per hour. For a relatively flat course like Garda I would have expected say 32 km per hour, certainly 30+, whereas it was reported as 26.4 km per hour over a period just under an hour. So the slow stretches were taken account of. I guess this is good because consistent, but feels irritating when riding long purple stretches.
If it is GPS problems in the tunnels leading to camera speed deemed too low as ~4 km per hour and tunnels being correspondingly short, is it possible to simultaneously scale camera speeds and hence tunnel length to recover the 'missing' tunnel bits?
I guess this may be too difficult - but thought I would ask!
In many of the tunnels (at least 8 times by my rough count) the speedometer display went purple and my speed was shown as about 4 km per hour for long periods of a minute or two (not the odd second). As I came out of the tunnel it went back to the usual display colour with genuine speeds (30-50 km per hour depending on the tunnel). So the effect seemed closely linked to being in the tunnel or not being in the tunnel.
Some of the tunnels were empty of traffic, so its not as if the route needed to be filmed slowly leading to a purple display. I am guessing the problem was something to do with losing the GPS signal in the tunnels so distances and speeds were recorded too small. Supporting this theory, the website has the course length at about 36 km (matching the corresponding website profile). whereas the profile shown in the VeloReality App is 26.8 km so it looks like up to 9 km of the course might be missing - lost in the tunnels due to GPS issues?
My reported average speed (correctly matching distance travelled with time) was quite impacted by the forced stretches at 4 km per hour. For a relatively flat course like Garda I would have expected say 32 km per hour, certainly 30+, whereas it was reported as 26.4 km per hour over a period just under an hour. So the slow stretches were taken account of. I guess this is good because consistent, but feels irritating when riding long purple stretches.
If it is GPS problems in the tunnels leading to camera speed deemed too low as ~4 km per hour and tunnels being correspondingly short, is it possible to simultaneously scale camera speeds and hence tunnel length to recover the 'missing' tunnel bits?
I guess this may be too difficult - but thought I would ask!