'Greenest,' 'meanest' vehicles of 2007

I don't know if it's my failing eyesight or what not, but every time I see CNN article written I always see CWN article and go *ugh*

 

Cool. The only car outscoring the Prius is Honda's Natual Gas powered vehicle. And since not everyone has access to natural gas as a fuel, the Prius pretty much wins. I was surprised the Cambrid scored so low, but I guess it got hit on mpg.

 

I take issue with American Council for Energy-Efficient Economy methodology for ranking vehicles. They use the following methodology:

"Three types of vehicle-specific data form the basis of the ACEEE's Green Book® ratings: tailpipe emissions, given by the emissions standard to which a vehicle is certified; fuel economy, based on EPA test cycles; and vehicle mass (curb weight)."

As you can see the ACEEE doesn't not use the actual data from EPA testing but instead uses the maximum allowed pollution for the emission standard that the vehicle is certified too. This causes diesel vehicles to be ranked as "meaner" than their gasoline counterparts even though they emit less total pollution. This is because high emissions of NOx put diesels into the T2 Bin10 category even though the other 4 pollutants are at Tier 2 Bin 2 levels.

Actual EPA test result from http://www.epa.gov/otaq/crttst.htm / mpg from www.fueleconomy.gov

GL450 (Gasoline)
--------Actual EPA Data------Tier 2 Bin 5 Standard
CO --------- 0.73----------------------4.2
NMOG ----- 0.0222--------------------0.090
NOx ------- 0.022----------------------0.07
Total ------ 0.7742---------------------4.36 ---(17.8%)
Fuel Economy 13/15/17 mpg

GL320 CDI (Diesel)
-------Actual EPA Data-------Tier 2 Bin 10 Standard
CO -------- 0.04-----------------------4.2
NMOG ---- 0.0032---------------------0.156
NOx ------ 0.48------------------------0.60
PM - -------0.003----------------------0.80
Total ------0.5262---------------------5.756---(9.1%)
Fuel Economy 18/20/23 mpg

The GL320 CDI only emits 9.1% of the pollution allowed by the Tier 2 Bin 10 standard it is certified to. The GL450 emits 17.8% of the pollution allowed by the Tier 2 Bin 5 standard it is certified to. This is why you can't just look at the Air Pollution Score of a vehicle to see what it's emission really are. The Air Pollution Score assumes that the vehicle emits the maximum allowed pollution for its bin.

The GL320 CDI (diesel) emits 47% less total emissions than the GL450 (gasoline) and gets 33% better fuel mileage! But the GL320 CDI is ranked as the 2nd Meanest vehicle sold in the United States. :blink:

I admire the idea of ranking vehicles, but their method is sloppy especially since the actually EPA data is available to the public on the EPA's website.

 

<div class='quotetop'>QUOTE(jhinton @ Sep 10 2007, 05:40 PM) [snapback]510259[/snapback]</div>

I was going to joke, "hey, this thread'll allow us to start another TDI thread" ... so I hit refresh, and loe and behold. We're off and running!
In fact, there's another TDI thread right under this one in the 'main forum' list.

 

<div class='quotetop'>QUOTE(hill @ Sep 10 2007, 07:11 PM) [snapback]510336[/snapback]</div>

Am I starting to sound like a broken record? :lol: I'm not going to argue that diesel SUV's are the greenest, but they are not the meanest either.

 

Alright, let's steer clear of diesels. What is the exact methodology used for the ranking? What precisely is it about the Kias and bottom Civic makes them greener than a Focus? They have 3 to 5 combined mpg over the Focus, but the Focus has a better emmission score. It has the same score in CARB states as the Prius. Even outside of CARB, it scores higher than the cars at the bottom of the greenest list.

 

Anyone else finds curious that they include the diesels rather than gas MBs? I would think the gas are worse based only in oil consumption.