I tow a lot with my durango, and would like it if there were a slider to specify when I used my vehicle to tow, and perhaps graphs that ignore my large dips in MPG due to towing. It'd be nice to have it able to be turned on for my truck and not my motorcycle, like a checkbox on the vehicle page that makes the slider available.
Thanks for the suggestion. This is something we can consider. We're very hesitant to add anything to the fuel-up form that complicates it, unless a large number of people will benefit. We're also pretty hesitant to add something else you need to set/worry about when you set up a new car. So my first thought is that this probably won't make it into the site.
For now you could track those times that you tow with a tag or note. That would at least give you an indication of which fuel-ups involved towing. You'd at least be capturing the data in that case. And if you're handy with Excel, you could export your data and tailor reports/charts to your own needs.
What about making a duplicate vehichle for your Durango, call it say Durango Tow, and add the towing fuel ups to that "vehicle" and your regular fuel ups to the original? That way you can track them seperately but still within the site's current parameters. As an added bonus someone searching for vehicle stats could easily discern between the towing fuel ups and the standard ones.
I think having two vehicles would be fine if you don't care about accurate individual MPG calculations. Fuelly uses the difference from full for each fuel-up to calculate individual fuel-up MPG numbers. If you're splitting fuel-ups between two separate vehicles, those numbers won't be accurate. You'd have to mark a large percentage of fuel-ups as *missed* because the preceding fuel-up was entered at another vehicle.
I think notes are a good way to remember this data and let others know how much towing is happening as well.
Why don't you just use the 'City%' slider for towing? Unless you live in a very dense city like NYC or SF the slider is pretty useless. I live in San Jose, CA which is kind of a big 'city' but it's all suburban driving and I actually get better MPG driving suburban traffic than I do on straight highway. IMHO, of course!