Accurate way to measure route distance
 

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?

Have you tried driving it in a normal manner? I often suspected FAS you loose a few thousand feet, but didnt think p&g effected it.

the issue is that i turn my key when i p&g and while in the off position momentarily the odometer doesnt run. the ultragauge still does so thats not an issue. it doesnt matter if i drive normal or crazy the ultragauge gives the same measurement. i just want to see what the best way to verify if my ultragauge distance is corrrect

Do you have a GPS or device like a smartphone with GPS? You could measure it out on Google Earth (or even see what Google Maps gives you when you find directions).

Kill switch. Even if you are key starting, the time needed to flip the switch is less.

A few people here don't like to use a KS because they have whatever reason, like to stop the IMA from restarting the engine when put in gear- But what I don't understand is this: Using the key off method, one has to keep the key off until the engine dies or it will restart (at least in the Mustang and Insight). If one uses a kill switch, everything runs normally, then flip the switch to ON and then crank over to restart. Instead of 3-6 seconds to kill the engine (depending on RPM at shut off, and engine) one has a half second of turn back, and turn forward.

ridewithgps.com ... You can use it to map your driving route, including elevation changes. I have checked it against a good GPS unit borrowed from a geographer I know. The site seems very good. Also, I found the free android app GPS Odometer to be pretty good too.

My Mazda's speedo/odometer stops when the key is turned off, so I wired in a kill switch that only kills the engine not power to the instruments, blinkers, etc.

Due to running taller tyres (in my case), I compared my odometer reading against my GPS (distance) over my normal commute (about 52 km) for a couple of days.

Keep in mind that your speedo and odometer can be off by different percentages. My speedo is 1% slow, but my odometer is 5.7% slow when compared to the GPS.

I wouldn't worry about it there are tons of things that can effect the reading on your odometer, tire and wheel size, EOC like in your case, the odometer itself can be calibrated poorly and many more. It's not really a big deal.

As mentioned, KILL SWITCH! I couldn't believe I waited a year before installing one. It's worthy every second of time to install. It will fix your accuracy issue (for key timeout at least).

Route wise, I usually map it out in google earth. Not sure if there is really a better way, but works great for myself.

Everybody says to use Google maps, but around my area it really isn't too accurate. On my route to work, Google does not show any road work that has been done in the last few years, and seems to think that several complete stops are cloverleaf interchanges. Probably not a huge distance, but I'll bet its off over 1/2 of a mile between 2 major intersections and the work that has gone on in the bypass I cruise on.

I've noticed between my vehicles there is as much as 1.5 mile difference in odometer reading depending on what I'm driving (motorcycle is the worse). Best bet would be to log the distance real time with a GPS unit...should be accurate to within a couple feet as long as you don't lose signal somewhere along the way.