mpg numbers are shown on website for 2016 Prius

Agree - Headlights, LED is low beam only on Corolla, and I do not remember when I used high beam last time. My 328i has Bi-xenons, so both low and high beams are HID (it is really a stainless steel shield, moving up/down in the lense assembly).
Difference I observed is, despite HID also cuts off sharply, there is enough side and top peripheral lighting, but not so with LED. Also as you said lighting is bluish, and in rain it is very hard to see in bluish lighting.

Yes, I know the difference between LDW and LKA (My Odyssey has LDW, not LKA),
Both 2015 Honda CRV, 2016 Civic has Lane keep Assist with active steering control. Lot of drive reviews are there on the net, but here is from horse mouth directly
Lane Keeping Assist System (LKAS) | 2016 Honda Civic-Sedan | Honda Owners Site
Edit: Also seems for $1000, honda has package of all those features even in base models

Yes, smartkey Touch sensitive. I know actual physical button vs touch sensitive ridge area(My Prius has buttons). Last Avalon I test drove has touch sensitive area, not a button. so are few other cars, but I do not see much advantage/value add there, instead of touching specific area I just press the button to lock.

I know, mine had only FCW, but Subarus I test drive has auto braking too.

But my priority in real world usage: Smartkey (use it every time in all my cars), push button start without key, Rearview camera with cross traffic alert, HID lights, Auto dimming mirrors (side and rear view mirrors which I really like on my BMW). Good sound system. Homelink is ok to have, but not critical, compass we can skip.

Remaining things, I see as unimportant gadgets, adding not much value. LDW is always off in my Odyssey, FCW is pretty accurate so it is on, but I never relied on any of those.
When I drive, I drive. I do not eat sand witches, play games on phone, no long phone calls etc. I hate folks who are immersed in their phone/make up at lights, and leave in the last second on orange leaving all other behind traffic light.

 

Most likely b/c they do not contribute to MPG

You don't think of lights in terms of MPG, but here is an example:
2 sets of 55w headliight bulbs (low+fog)
6 parking bulbs (4 front/2 rear) 15w x6
total load ~300w

Engine efficiency ~20%, alternator efficiency 70% total load ~2.2kW, or 3hp.

if you count that car needs ~11-17hp at highway speed to push it alone, 3hp is big add on.. Granted Prius ICE is more efficient, and comparing to non-hybrid there is also regen braking, still there are some MPGs to be found in changing bulbs to LED, whatever small it could be.

Another reason why you need different relay for LED turns which is not as widely used and therefore more expensive, so bulbs+relay got chopped off by bean counters. Saved them $10 per car or so.

From the pics I've seen you don't really want 4wd in Gen4. The clearance is 11cm (4") no place to route exhaust. It is not useful in snowbelt as we usually get more snow due to lake effect, and will create bad rap from those who will try to take it off road. We scrapped the bottom of Gen3 many times on speed bumps and in camp sites.

 

must be tough to make a short hatchback with a low cd.

 

Wrong, you calculated fuel power not engine drag, that 2.2 kW means ~0,25 l/h gasoline, how much will that translate to your MPG depends on your average speed.

 

Vehicle Coefficient of Drag List - EcoModder

yes generally longer narrower cars do better.

 

Cd values for the mirage on the net seem to vary but when you look it up here MIRAGE / SPACE STAR | MITSUBISHI MOTORS they seem to think that Cd = 0.30
Compared to Cd = 0.24, this is 25% higher

 

Compared to this list, the Gen 4 Prius has the lowest Cd of any vehicle in production and mass produced (not a concept/prototype car or only made in a few copies).

Probable also best CdA for its size.

 

???

 

That list is quite out of date; it seems to end in the early 2000's.
The Tesla S and new Sonata hybrid both have a Cd of 0.24 like the new Prius.
CdA in sq.ft.
Model S: 7.279
Sonata hybrid: 7.034
Prius: 6.370

I've been missing stuff.

 

that list is very sporadic. If you follow link above to 12 best aerodynamic cars you'll see that MB CLA has better Cd 0.22. Looks alot nicer than Gen4 too.

Eclipse had higher Cd but lower CdA, so Nissan 240SX.

 

FYI, MB CLA only specific version in Europe is with Cd 0.22, not North American version. That too quoted by MB, but not third party verified. NA is more like 0.30.

Also, Prius Gen 3 Cd is 0.26 as per 3rd party. (Tesla has the lowest).

Drag Queens: Performance Data and Complete Specs

Infact even old version of Honda Insight tested at 0.30 though listed as 0.25. But it has least CdA, so it helps on highway.

 

Does anyone know what speed they are referring to when they quote highway mileage? I read that it is much lower than 70-75 which is the average speed here in South Florida. I can still get close to 50mpg at 70 which to me is outstanding.

 

I wonder how much of the difference has to do with wind tunnel differences?

The high speed cycle hits 80mph, but only for brief bursts. Average speed for it is 48.4mph, which is a tenth of a mile faster than the highway test cycle average with a 60mph top speed.
Detailed Test Information

Remember, the city and highway numbers are based off those corresponding tests. The other 3 cycles are used to determine the adjustment for the window sticker numbers.

 

I'm betting most of the Cd differences are due to certain peoples/companies wishes. Just based on the last year or two of "cheat discoveries".

 

I do not think Wind Tunnel differences would make substantial differences in the obtained Cd, more to do with whether quoted Cd is based on modeling/FD analysis vs real wind tunnel test results.

certainly possible. That is why testing all these in same wind tunnel gives relative Cd. I think GM and Toyota has access to best facilities(No wonder their 3rd party tested Cd is close/same as listed).

Edit: Here is link about GM climatic wind tunnel (check the video too)
Rain or Shine, GM’s Climatic Wind Tunnel Always Controls the Weather - FastLane

Company wishes - reminds me of Ford fiasco for mileage of Ford C-Max Hybrid and Fusion Hybrid which were reduced twice, still does not match real world. Still boggles my mind how Ford got away without any penalties despite large gap(Originally 47 vs now 39), where as Hyundai/Kia paid huge penalties for 1-2mpg differences.

 

Practicing while waiting for the true, EPA table, I generated this chart:

• Started with the EPA table listing all models for 2015
  
• Left axis is both MPG and drag HP
  • MPG is the CAFE listed miles per gallon
  • drag HP is the coast-down coefficients calculate at 5 mph speed steps - this is the amount of power needed to hold the vehicle at a steady speed.
• X-axis is the speed
  • 0 is where the CAFE MPG falls
  • 5-75 mph is the speed steps - the coast-down starts at 71 mph so 75 mph is a projection
• Right, z-axis is the model and (make)

So now we can start looking at sets of 2015 vehicles:

1. PRIUS c (53/50/46)- as expected, it is the CAFE leader. Now due to the modified EPA weighting, it does not have the highest composite MPG but it is an awesome efficient, compact car. It is the only car to beat my 'stunt' 1000 mile tank.
   
2. PRIUS Plug-in and PRIUS (51/50/48) - very good sharing nearly identical performance.
3. ACCORD HYBRID (50/47/45) - surprising drag curve but hurt by the EPA modified weighting. Still, impressive.
4. Tucson Fuel Cell - in Alabama, it is sitting on cinder blocks in front of the Hyundai dealer. Strange how the EPA has given a suspiciously high, CAFE rating. All FCVs need a closer look as someone may be 'cooking the books.'
   
5. CIVIC HYBRID (44/45/47) - long in the tooth, it really needs a refresh.
6. PRIUS v (44/42/40) - the wagon, the static drag coefficient (*) suggests something bad is happening
7. Fusion (HEV) (44/42/41) - another big boy with a static drag profile problem.
8. Camry Hybrid LE (43/41/39) - ditto
9. Camry Hybrid XLE (40/40/38) - ditto
10. Jetta Hybrid (42/45/48) - they don't know how to do a hybrid, yet.
11. ES 300h (40/40/39) - big boy with static drag profile.
12. C-Max HEV FWD (42/40/37) - ditto
13. C-Max (PHEV) (42/40/37) - ditto

Now the one thing that really opened my eyes is the effect of the static drag coefficient ("Target Coef A (lbf)"). There is a correlation between weight and the static drag force. This has a linear add to the vehicle drag power and is the largest coefficient. I'm beginning to think we need a different approach to wheel bearings.

Perhaps pressurized oil bushings might reduce the drag and at the same time handle the high loads. It may also be possible to use a less viscous grease. It would have a maximum effect on the heavier vehicles.

Bob Wilson

 

Would be nice if you can add the drag hp @ 75 mph next to model (make) as it is difficult (to impossible) to read it on the chart.

 

Let's see if I can attach the excel file.

I could not find an excel function to add another vertical axis to this chart. I could put it in PowerPoint and manually add them but that would be 'ugly.'

Bob Wilson