Accurate way to measure route distance

[nathan01xl]

I have looked into a kill switch and haven't been able to find a way to do one on my truck. There is no injector fuse which I can wire into. My only options IIRC are into the ignition or fuel pump, which don't sound much better than what I am doing now.

[nathan01xl]

ridewithgps is confirming the distance google maps gave me... this is actually good news because it means i have been underestimating my distance traveled for a year by 2%.

[UltArc]

I don't use a KS on the Insight, on the Mustang I use the fuel pump fuse.

I flip the switch, and have to wait for the RPMs to drop down- but my key stays in the ON position, and miles are still counted.

[nathan01xl]

Originally Posted by UltArc

I don't use a KS on the Insight, on the Mustang I use the fuel pump fuse.

I flip the switch, and have to wait for the RPMs to drop down- but my key stays in the ON position, and miles are still counted.

what type of switch are you using?

[D.O.G.]

Originally Posted by nathan01xl

ridewithgps is confirming the distance google maps gave me... this is actually good news because it means i have been underestimating my distance traveled for a year by 2%.

I haven't checked their accuracy in regard to distance, but I know ridewithgps's elevation figures aren't always what you expect.

I mapped my commute route and found that it seemed to showed ground level, not road level.
It didn't show road cuttings or bridges and living in the mountains, I encounter both a number of times.

[aerohead]

Originally Posted by nathan01xl

The more I p&g the more error my odometer shows when determining total distance traveled. Fortunately my ultra-gauge is pretty well calibrated (accurate even to radar speeds which show 2x along daily commute) so I don't pay much mind to it. However this last tank i really used p&g a lot and my odometer was showing a really low reading (585 when really went 600).

SO... I decide to check my commute distance via Google maps, and Google is telling me my commute is nearly a full mile longer than I had thought. So that leads to my question...

How do you all verify your route distances?

If you drove your route 'normally',you'd capture what the car system 'sees.' Your speed sensor is not 'transmitting' to the CPU when the power is off,so it's 'blind' during P&G.You could compare that with your GPS.
Since the electronic speed sensor is pulsing with every rotation of your output shaft,I suspect that it has a higher resolution than the GPS.
I don't do P&G and it can be 760-miles between fills,so a small deviation doesn't matter over those distances.
The shorter your route,the higher the potential for discrepancy exists.

[user removed]

Originally Posted by D.O.G.

I haven't checked their accuracy in regard to distance, but I know ridewithgps's elevation figures aren't always what you expect.

I mapped my commute route and found that it seemed to showed ground level, not road level.
It didn't show road cuttings or bridges and living in the mountains, I encounter both a number of times.

Does this mean GPS readings do not show elevation changes that would affect distance travelled, something I had wondered about.

regards
Mech

[Cobb]

So, if I go on a route that has a steep grade change the directions only consider distance from a linear 2d dimension vs 3d or vertical dimension?

[oldtamiyaphile]

Originally Posted by Old Mechanic

Does this mean GPS readings do not show elevation changes that would affect distance travelled, something I had wondered about.

I believe this is the case. In the real world most trips are A-B-A so it will usually average out. Even my super expensive 'high accuracy' $700 GPS doesn't do elevations very well.

On the other hand, if the elevation is 200m out, it's a lot if you're measuring elevation, but not really much when you're measuring a road trip distance.

This can be tested by comparing speedo error going up hill vs down. You'd need a SG or other digital read out to compare the GPS to.

[Cobb]

You spent about 600 more than I did for my refurbished one with lifetime maps n traffic from ebay. I never paid attention to the miles as I assume the margin of error was enough to screw up any sense of accuracy. Plus I take detours for traffic reasons, days I only feel like making right turns, days I feel someone is following me, days I want fast food or inconvenience items, etc.

Originally Posted by oldtamiyaphile

Even my super expensive 'high accuracy' $700 GPS doesn't do elevations very well.