MPG Normalization

[theholycow]

That's worth a try. The opposite is also worth a try. Both can be backed by theory and real world data.

[GasSavers_maximilian]

My intuition's no use for these multi-input tradeoffs. Just have to try 'em for long enough and keep track. I just removed my passenger mirror so I can't try anything until I establish a new baseline. Besides, summer tire season's almost here (we only got 4" of snow today)!

[GasSavers_maximilian]

The EPA combined mpg estimates appear to assume 60% city driving and 40% highway (worked it out from the ratings of my car). I just analyzed the routes that comprise over 90% of my driving and the reverse is true: 60% highway (two lane state highways with a speed limit of 50, but that's what I drive on the big highways anyway), 40% city. When I compute a new combined mpg with those fractions I get 30 mpg. In fact, since the "city" driving is really just small town driving so there are almost no stops, it probably should be a little higher than that. I figure it's close enough to the adjustment for all the hills around here that I can neglect it.

Any objections to my updating my combined reference number? It makes my % over EPA score worse (by 3.3%).

[theholycow]

fueleconomy.gov defines combined as 45% highway, 55% city. I believe by "highway" they mean freeway, not 50mph two lane state highways.

It lists your 2008 Accent manual as 27 city, 29 combined, 32 highway. Those are the numbers that you should have in your "EPA Values" section of the garage entry to fairly compare against other drivers.

FWIW, my driving works out to about 55% freeway, 45% town/two-lane state highway and I compare to my EPA "Combined" rating. My choice of where to live and work (and therefore my commute) are reasonably part of my hypermiling, IMO. Anyway, traffic lights and stop signs definitely mean you're not driving in what the EPA considers "highway", though those Vermont two-lanes do have long runs of no lights or stop signs. EPA combined rating is a fine baseline for you.

[GasSavers_maximilian]

Originally Posted by theholycow

Those are the numbers that you should have in your "EPA Values" section of the garage entry to fairly compare against other drivers.

Your idea of "fairly" and mine differ (gives me an inherent advantage), but you're the moderator! I guess unless everybody worked out their combined it wouldn't help in total. I'll just make a note in my description.

.55*27 + .45*32 = 29.25, so the rounding is what gets it to 29. That means the decrease from changing to 30 would be down to 2.5%, which is starting to get pretty small anyway.