Please explain MPGe

Sure, but ultimately, you care about efficiency for three reasons:

Cost per mile, which MPGe doesn't cover
Resource usage, which MPGe doesn't cover
Global warming potential, which MPGe doesn't cover

 

Sure, however all of that data is listed on the car stickers where the MPGe is also shown.
BTW, MPG doesn't give you that information either. It is just that we are so used to doing the conversions in our head, it doesn't matter.

 

It does if you are starting from the same fuel source. Then the MPG (e or otherwise) is proportional.

For example:
If car 'a' is x mpg
and car 'b' is 2x mpg

Then car 'b' costs half as much to fuel, uses half the resources, and pollutes half the amount.

Which is why I keep saying that MPGe is only useful in cars with the same fuel source.
Don't mix MPG(e) electric with MPG(e) fossil fuel. Nonsense is sure to follow.

 

@Oniki, your statements have several errors again. For the benefit of other readers, I would refrain from making statements if you are ignorant on the subject. Here's one example to refute your latest claim that you can use MPG to compare pollution: car 'a' and car 'b' use the same amount of fuel on a 100 mile trip. The cars are identical in every way except that car 'a' does not have a catalytic converter and car 'b' does. In this case, car 'a' sends more pollutants into the atmosphere than car 'b' even though they have the same MPG. Another reason why MPG is not reliable for total pollution is that it does not reflect the pollution that went into manufacturing the vehicle, which is something you really can't ignore. Comparing pollution is complex and using MPG to compare pollution is unreliable. I already explained why MPGe is useful in comparing energy efficiency and costs between vehicles of any fuel source so I will not repeat that.

 

I have only lived in areas where all cars have cat converters. I was not thinking of NC.

You are right though, I should have expliicitly limited the emissions to CO2