I like the sound of the new additions (although as noted it is important that the data entry process be as simple as possible).
Incidentally I have been tracking temperature (high & low) for the last couple of years on my tanks, and I have found that there is a very strong correlation with mpg. (That's on a 3-cylinder diesel). So IMHO tracking temperature is a good idea.
I track an estimated average temp in my cleanmpg log, but it's like I say: estimated. And now, having a car (which I rarely use when it's not winter), this estimation has reached a new level: I fueled it up in the middle of May, I don't know which days I used it, and I have no idea about the temps on those unknown days. And the fuel gauge still shows 4/8 bars... I'll have to guess when this tank ends, really.
But temperature and FE really has a strong correlation, even with vehicles only with internal combustion engines, it's useful data.
Knowing the actual temps when you drive could be done by connecting Fuelly to a bluetooth ODBII reader. Essentially we could understand when/where you are driving and automatically append the local temps from a weather API.
We've ordered dozens of ODBII readers and waiting on them to arrive to start testing and hope to be able to allow some Fuelly members to help us beta test. There is are a LOT of issues and use cases surrounding ODBII data that we need to discuss and think through.
The years ahead should be a lot of fun. Plenty of neat projects to think through and from what I've seen Fuelly has a lot of really smart users. It's exciting to think about what we can accomplish together and how our data might help the auto industry better.
My car shows me the current temperature on the dash, so over the tank I try to remember the highest & lowest that I've seen. I use the mid-point between the two when I am calculating the correlation with mpg. OK it's not totally scientific but it's adequate for the purpose.
Many of the features I think will be a great addition to the website and some, not so much, but alas what is good for someone is not always good for the next guy.
Out of the features listed, I think that being able to search and filter results by transmission type and engine size or trim level will be a biggie for me as I drive a manual in a car that is usually dominated by automatics (e90 325i) and i'd like to be able to compare my results to others with the manual transmission only. Or with my last car, I had a Grand Prix SE with a 3.1L engine which was rare to find. Most others had a 3.8L and it was a lengthy process to find the others with a 3.1L engine to compare numbers with.
Adding the ability to add in the octane, fuel additives, and maintenance I believe is a good thing as well. As would if we could specify which gas station we were at to compare our MPG from one gas station to the next, especially today when one gas station might add 10% ethanol and the one next door might only add 5%. I use aCar and Gas Cubby myself in addition to Fuelly and while it might be hard to compare the maintenance between users, it is fun and helpful to see it all digitally on one screen to see how much you spent, the life you got out of certain wear parts, and the such without sorting through messes and stacks of papers. And if the option to record a fuel or oil additive is added, I think that the ability to search site wide for the people who do so might be interesting. That would allow you to see if any additive actually works and to what extent.
Some of the things that I think are a bit much is the temperature and elevation, although once enough people have recorded fill ups with these features, the ability to see the difference between sea level and a mile up or in a hot versus a cold climate could be interesting.
Sounds great. One thing i miss is the option trailer. This drops the average.
Second is it possible to made a distinction to % highway / % city travel. Measured by odb input (time between rpm changes due gear shifting. city every corner, at the highway you have low rpm changes)or measured by road speed.
htahta, I agree, ODBII would allow for better city/highway estimates. Actually, my personal belief is that city/highway is an outdated paradigm. For example someone might live on a country road with a top speed of 45 mph have have very few stops between their home and work. That's not city nor highway driving but they are probably going to get better MPG then someone in a normal gas car in stop and go traffic.
My theory is that it's possible to provide drivers with more data about their driving style and commute. I think it's possible to then use this data to provide custom estimates on how another vehicle would perform for for you based on your historical data. This would require a lot of work but I think it's an achievable goal.
An option to check if you are towing would indeed be a valuable item to denote on a fuel-up as that would probably impact MPG considerably.