MIT finds fuel efficiency has not improved much

For the most part, marketing is comparing current models to recent models (of the past ten years) which is in fact an efficiency increase. A mid-size SUV does have better EPA ratings than one of similar size from late 90's.
Now that being said, yes, we could all be driving 48 MPG autos if our Chevy Cruzes still weighed the same as a 1976 Honda CVCC. But consumers are not just demanding efficiency, but also safety. Strong steel cages, air bags, etc all add to the weight. History has also shown us that cheaply outfited economy cars do not serve all demographics. To get some of us more senior or experience drivers in a small efficent car, you need to outfit it with some comforts. This isn't just an American idea, European compacts are not econoboxes.

All anecdotal, I know, but from personal experience:

My 1984 Honda 1.6L DX got 40-42 MPG with A/C on the highway, but todays' equivalent model doesn't get anywhere close to that. Tighter and tighter Emissions requirements and more and more mandated Safety equipment have combined to increase vehicle weights dramatically!

My 1970 AAR 'Cuda with 340 cid V8 engine had a curb weight of 3200 lbs; our 2011 "compact" Cruze LTZ weighs more!

I used to own a 92 Geo Metro hatchback. At that time in my life I did a lot of travel for work, sometimes commuting 100+ miles each way to an engagement for weeks on end. The company I worked for would pay for lodging, but commuting put a lot more cash in my pocket. Anyway, to the point, in mild weather when I did not have to run the AC, I would regularly get around 40-44 MPG commuting. However, the trade-offs for that kind of mileage include a spectacular 55 HP 3 cylinder engine, no airbags, and the feeling that just about every other vehicle on the road could squash you.

I think I'm going to have an aneurism on trying to figure out why someone from MIT wasted their time with this. I thought it was a pretty well known fact

FWIW, Light-Duty Automotive Technology, Carbon Dioxide Emissions, and Fuel Economy Trends: 1975 Through 2010 | OTAQ | US EPA is updated semi-regularly. The Executive Summary there is worth at least a skim...

When I bought my Cruze the mileage capability reminded me of my 1979 Ford Fiesta Sport 1.6 litre 4 speed manual. The best that approx 1800 lb car could do on the highway was 42 mpg. What is truly amazing is how my ECO at 2964 lbs with a 1.4 litre has way better performance and fuel economy. Efficiency is way up on modern cars. The Fiesta was fun but was my last Ford - it rusted out very quickly.

you cant have stricter emissions and more mpg, it will never work. Top gear drove a VW polo with a diesel engine from 1990 and it got 75mpg! The motor is not made anymore due to emissions.

Cant have the best of both worlds.

Matt Man said:

you cant have stricter emissions and more mpg, it will never work. Top gear drove a VW polo with a diesel engine from 1990 and it got 75mpg! The motor is not made anymore due to emissions.

Cant have the best of both worlds.

Click to expand...

You can but you sacrifice drivability and performance. Tuning triangle; emissions, drivability, and economy.

also you want to throw in safety and basic features

the cruze has everything you would really want in any car and is safer than others... the price for that is 3,000lb+

Matt Man said:

you cant have stricter emissions and more mpg, it will never work.

Click to expand...

...exactly! In fact, in order to meet the stricter emissions requirements, all engines must actually burn MORE gasoline than necessary, especially during cold-starts, so as to "burn-off" everything inside the catalytic convertor(s). And, this "richer-than-necessary" condition also occurs (but to a much lesser degree) when the engine is warmed up and running in "closed-loop" mode under control of the engine computer module (ECM). It's happening ALL the time!

...simply put: CLEAN AIR = LESS MPG than optimally normal.