Model Stastics?
 

Maybe I just like statistics too much, but I was wondering if when doing the "browse vehicles" thing, if you could have the site crunch statistical numbers? Say, Median, Mean and Standard deviation (to see how normal 51mpg from a Jetta TDI really is), and possibly median for that model (ie, take data from vehicle 1, 2, ..., n, and crunch all numbers as though it were one vehicle)?

Also, if you had personal statistics (specifically Z-score as a function of your model), you could put a "Your profile has a [profile confidence interval] chance of getting around [#] mpg in this vehicle" on the browse vehicles page. ...though, that may be getting too complicated.

And, since I'm asking so much as it is, other than the obligatory pony request, maybe a model year filter, too?

I can honestly say this is the first request we've had for these statistics. I agree it'd be interesting to see the numbers, but I'm not sure about how useful they'd be for everyone. I think this is a good argument for adding an API, so others can take the data and analyze in ways we haven't considered.

You can filter models by model year. Just browse to a specific model page and click the year header to narrow things down to just that year.

I was about to ask for a similar thing, except more for trending. I would like to know if fleetwide fuel efficiency is decreasing. That is, since winter is nearly at end in many parts of the country, should I see an increase in fuel efficiency or a decrease. Also would be nice to compare the fuel efficiency of vans vs trucks vs cars vs hybrids.

I think that Londubh's suggestion would allow those comparisons to be made. An API with XML/JSON/RSS or other transformable output would be great if you don't want to clutter up the site. Then I could use the XML/RSS/JSON output to create a mashup in another site (like the IBM mashup center). btw i am not a programmer, I just ran into the ibm mashup center site and it has got me thinking about what I would like to feed into it. I think you would also see this used on a site like facebook, or other googly site.