I was thinking about the vehicle database the other day while driving. If people are given the option to either manually calculate their mileage and input it into the database or just go off of what the vehicles trip computer spits out how does the database keep the stats accurate. As others have posted and I have found out for myself the vehicle trip computers are off by about 3mpg which would skew the database if this were unaccounted for. Is this accounted for within the system and if so how?

Pretty sure its the honor system.

Most will take their ODO miles divided by fuel pumped at the tank refill versus just using the FE gage.

The dbase does not adjust anything.

My point was that for the people that just enter the MPG figure from the trip computer this will cause the database figures to be skewed higher than they actually should be since the trip computer is always higher by as much as 3mpg per tank, thus making the AVG MPG for the database slightly higher. I know I am probably being anal about this but it was just something I was thinking about as I was figuring out the profitability and efficiency of my TCH vs. my previous vehicle. A few MPG over the course of a year does add up and make the numbers significantly different. If I used the numbers provided by the trip computer then it would look like I was saving more money than I actually am, which would then make the amount of time to witness my ROI shorter when in fact it's not.

Is it going to make a significant change to the database? I don't know, probably not. But, then again it might.

Not sure how the camry works but the HCHII displays an mpg that is consistently is 1-3 mpg below the actual. There is a lot of variability with the amount of gas you put in the tank but over time, the manual method seems more accurate assuming the gas stations are honestly pumping a real gallon!

I have read a little about how the pumps don't pump correctly unless they are calibrated frequently. I believe I read that hear.

"Not sure how the camry works but the HCHII displays an mpg that is consistently is 1-3 mpg below the actual."

That's while I feel that the numbers that the database is putting out are skewed slightly. I don't know how much but I am hoping to get an idea with some analysis that I am doing.

Well I finished my analysis on the TCH database info and combined with some data obtained by people who hand calculated their mpg avg it only came out to be .29mpg lower than what the database is reporting. So when all of the data is averaged out it is relatively accurate.

Dan,

Dont worry - your TCH will pay for itself and your FE will rise as Spring comes to Chicagoland...

I'm not worried, just my curious nature at times. Oh the TCH was definitely the right choice for me. I am seeing a realized 52% savings in fuel after 3 tanks. My Bonneville SSei was getting 19mpg combined avg and my TCH is currently at 36.5 lifetime avg. (This tanks the computer says 40.6 right now.) The reason why my savings is higher than it looks is because the SSei required\recommended premium fuel. So the TCH is not only better on MPG but also price per gallon.

The database isn't scientific; we're pretty open about that. To give an impression otherwise would be irresponsible and incorrect, so we do damage control instead.

We can't control how people get their figures, so we tell you there are multiple ways they're calculated.

Visit my newly-acquired website, Volconvo Debate Forums!

Well I bought my TCH based on the fact that this site claimed the avg mpg reported was 37MPG and now I find that it is off by .29MPG!!!! This is unacceptable!!!

Actually it was nice to see how close it really is. This is a great site and I actually did decide to purchase my vehicle based on information on here, combined with actually checking the car out in person.