gps speedometer non g.s

[g.s.john]

question for the knowedgableon on here,
in my company car i have a road pilot scamera warning device and a garmin nuvi 200 gps both indicate speed both showing the same figure how accurate are these readings?
Would any data from these devices be admissable in a court case?
thanks in anticipation

 

[Bear]

The GPS devices are almost certainly more accurate than your car speedometer but, because they are not certified/homologated/some other verb they are of no value in court. The speedometer in my Ford shows 70 when my Garmin shows 66 so there's not enough in it to worry about for me but if your speedometer boasts like a politician at election time then get it checked.

 

[Schtum]

All threee VAG cars - a MkIV Golf, a MkV Golf and a Skoda Fabia vRS - we've had recently have indicated 80 mph on the speedo when five different GPS units - a Streetpilot III, a nüvi 760, a nüvi 770, an eMap and a latop running MS Autoroute and a Microsoft GPS mouse - have indicated 76.4 mph.

We've just acquired a BMW 123d and I haven't had the chance to calibrate the speedo on that against a GPS unit yet but SWMBO has suggested that its speedo is more optimistic than the VAG ones.

The GPS speed reading is pretty accurate so long as you're travelling in a straight line and on a level surface. It's also dependent upon you travelling at a relatively steady speed. Since an NMEA signal updates at a frequency of 1 Hz, it can't keep up with rapid acceleration or deceleration.

HTH

 

[D6]

speedos always read more,
if they read less and you got done for speeding, you may have a case against the manufacturer?

 

[(RIP) ugg]

speedos always read more,
if they read less and you got done for speeding, you may have a case against the manufacturer?

thats why my quest says im doing 30 mph, but my speedo on the 1100 reads 35mph on the bike

so if i do 30mph on my bike speedo, ill never get done for speeding
because im actually doin 25mph


ugg

 

[g.s.john]

thanks gents what you have said bears out what i am seeing on my speedo and gps devices,
hope to see some of you at the g.o.c and three peaks