If you want to compare the Prius against anything, you can compare it against the Jetta or other small cars if you like, and the Prius will do quite well considering its a full car class bigger. But you’re better off comparing it against other cars in its class, such as the passat, the ford taurus, the opel vectra, etc. assuming what you need a mid-size car, and your seeking to minimise the environmental damage of that. If you don’t accept that, then compare a Jetta and a push-bike. Obviously the bike wins environmentally, but then it’s not going to get you, your spouse and your 3 kids anywhere is it?

So, if you want to use as little fuel as possible and be as green as you can drive the smallest car you can put up with. If you run it on diesel rather than petrol you’ll be doing a good thing on balance. If you go for a small engine you’ll be doing the right thing. If you can get a hybrid version of the car you need you’ll be doing a good thing because hybrids have far far lower emissions while delivering the same and usually better fuel consumption under normal driving conditions, when comparing cars of the same class. That is all there is to it…Why is this issue one that creates such debate, with recycling of the same old arguments derived from a very few original and incorrect newspaper stories?

If rolling over is a “handling” problem then I doubt I’ll ever convince you of anything, but here goes. I did a little research on the A-class and here is what autozine.com had to say: “Mercedes eventually solved the problem, but in the process it introduced severe understeer and a stiff ride to the A-class, ruining its original sweet driving manner. Still, once it restored customer confidence, some 1.1 million cars were sold.”
So, by giving the car worse handling, it made it safer and it sold well. http://www.autozine.org/html/Mercedes/A_class.html

What you say about larger wheel size on the same car is true. I was thinking of wheel size between generations of the same car. The Ford Falcon used to come with 14″ rims. It now comes with 16″ rims. The aspect ratio hasn’t changed much resulting a larger radius tyre which does give better ride comfort, all other things being equal.

I don’t see how diesel wins for the highway with the same economy. Given that diesel has about 17% more CO2 emissions than petrol, I find it difficult to believe that the extra co2 used in creating the hybrid isn’t made up for by the cleaner fuel over the lifetime of the car.

Diesel may very well be cheaper at the one service station you sampled but the long term average difference is clearly in petrols favor. http://au.maps.yahoo.com/fuelwatch/maps_fuelwatch_diesel.html#data

The Jetta is Mid size according to VW. “The quintessential VW mid-size sedan just got promoted” www.newjetta.com

I notice you have gone from claiming that they need a new battery every 5 years to pointing out some degradation issue that most normal driving patterns will never see. Interestingly, I found a forum where a person claiming to be a veteran Toyota senior Product Specialist .He said “being mass produced since 1998, Toyota has NEVER had to replace even one battery due to failure, and many vehicles have over 250K mi.” That comment was made in 05. 7 years, over 100,000 vehicles. The batteries are fine.

RAV4 does not have good handling, it has at best average handling in that it will not try and kill you when you change lanes.

Mercedes failed a handling test.

Wheel size almost always degrades comfort due to less sidewall and higher unsprung mass. Demand for ride comfort has not driven an increase in wheel size ever.

That conclusion is backed by no correlating data. Your personal predudices notwithstanding.

That’s what I said, diesel is better for highway, Prius wins in the city.

More or less polluting depends on which metric you choose to look at. Over the vehicle life cycle the Prius scores poorly do to it’s resource hungry manufacturing.

As I look out my window diesel is 5c per litre cheaper than petrol. LPG is a third the cost of either.

You stated the Prius was a medium luxury car, the comparison with a Jetta was simply to refute this, it is a small car, Compare it with a 307 diesel or an Astra. It is an expensive way to buy a small fuel efficient car. Add toys to taste if you wish.

Claiming anything on the basis of taxi type use is pointless. Toyota acknowledges that if the Prius battery is not topped up every two weeks then it can degrade.

A little internet research shows me that the Jetta is only as fuel efficient as the Prius in continuous high speed highway driving. It gets comparatively worse the more city like the driving becomes. Not to mention that in Australia diesel is more expensive per litre and polutes more per litre than petrol. In pure enviro or fuel cost per km, the Prius wins. Diesel comes a close second.
The prius is $9,000 more than the jetta but it does come with leather (what kind of luxury car comes with cloth seats?) Sat Nav and a killer sound system as extras. Delete thos features from the Prius and the difference is $1500, the Prius is an auto but the Jetta has a couple of extras (heated mirrors, dual zone instead of single). The Prius has a 5 star NCAP rating, the Jetta 4.

The 5 year battery claim is rubbish. So is the enviro claim.
The batteries have lasted over 350,000km’s in a taxi and one engineer that looked at them said they would expect the batteries to last at least 15 years from new, probably a lot longer. There is a bounty on the batteries so they are recycled not thrown away.

If you knew anything about the car industry you would know that performance and handling is one of the BIG marketing points, just look at how wheels/tyres and brakes continue to grow. There’s also the small point of passive safety, the chance of avoiding an accident in the first place. Look at how embarrassed Mercedes was when their new A class failed a handling test. Toyota have kept extremely quiet on just how poor the Prius is in this department.

If people weren’t interested in handling why would Porsche have made 2.1 BILLION EURO last financial year.

How you can call the Prius a medium luxury car is ridiculous. A VW Jetta is practically line ball for interior space, $10k cheaper and just as fuel efficient in anything other than constant city driving. AND you won’t have to replace a monsterous pack of enviro unfriendly batteries every five years.

I’d also like to point out that the Prius is a medium sized luxury car and any comparisions on price or fuel economy should be made on an equivalent basis to have any meaning.

The golden fuel systems (formerly greasel.com) FAQ discusses this a bit. They obviously aren’t a disinterested party, but it pretty much matches what I’ve heard from the people actually using the stuff. OTOH, there aren’t nearly as many automotive diesels available here in the states, so it is certainly possible that some of the others have problems.

There are also plenty of dissenting opinions.

The cost of making a mistake is also obviously higher with a new car, not to mention the risk of voiding your warranty.

I don’t think I’d try it on a brand new car, at least not without very reliable reports from someone who had already done it. OTOH, given a 90s era TDI with a value of a few thousand dollars and reasonably plentiful junkyard parts, I wouldn’t hesitate too much, on the understanding that there is some risk of having to replace the engine.

Most modern automotive diesels are pretty fussy, though. They’ll run fine on biodiesel, but not on SVO, at least not without major work.

With a lot of diesels you can get away with mixing some vegetable oil in with your mineral diesel. More than a trivial amount, though, and you can be dicing with an engine rebuild, with a lot of modern cars.

Those old Mercs, though, might well work on coal dust if you could find a way to get the fuel pump to move it :-).

The Prius engine achieves the same per joule efficiency as a diesel engine, and switching to a diesel engine would also provide more weight, and less perkiness from the engine. You could achieve nearly the same figures as a diesel hybrid by simply removing a lot of weight from the vehicle and using a turbodiesel.