"A $100 tax rebate from the government will not go very far even with a 20mpg car."

You try to make it sound as if a 20mpg car is something astounding. I don't have a hybrid or a diesel and I achieve 38mpg mixed driving in a car that can run the 1/4 mile in just under 15 seconds.

Minicars as such are not likely to get very far in the US. Aside from the cultural elements ("small cars = un-American" mentalities) , crash safety regulations make it pretty much impossible to sell anything smaller than a Honda Fit (96.5" wheelbase, 157" total length, 2500 lbs.) in this country.

Even the Scion xA comes in at a similar 93.3" wheelbase(154" total length) and 2400 lbs. By contrast, a nice minicar, the Daewoo Matiz (as a GM subsidiary, Daewoo sells the Matiz under Chevy, Pontiac and other nameplates in various international markets) has a 92.1" wheelbase, 137" total length, and weighs around 1800 lbs. It gets great mileage (typically estimated at 45 mpg, averaging city and highway), but is both light and tiny, making it a safety risk. An American company (GM) makes it, but they can't sell it in this country.

I once read in an IIHS document that size is far more important than weight, as a rule of thumb, when estimating safety. A car built with light materials, but physically expansive, has room to crumple and slow the radical deceleration which is the root of most accident injuries. It is therefore fairly safe. Furthermore, smart engineering, and the use of advanced features like ABS, stability control and side-impact airbags, both reduce the chances of crashing, and the severity of a crash if one should happen.

High weight contributes to poor economy far more than large size contributes to poor economy. It is possible to maintain expansiveness for the sake of safety while reducing weight for the sake of economy. Parking in tight spots would remain an issue.

In truth, we could increase overall fleet economy and crash safety in this country by simply moving as many motorists as possible out of SUVs / pickup trucks and into medium or large sedans. As I have previously observed, sedans are typically safer than light trucks of the same overall weight and passenger capacity (less prone to roll over, in large part), and also get better mileage. Someone once suggested a tax scheme, where vehicles with worse mileage than 30 MPG would pay extra taxes, while vehicles with better mileage would get a rebate. That's not a bad idea. Enacting a similar one based on safety would also be a good idea, and would likely (perhaps to some motorists' surprise) result in more transfer from SUVs to medium cars than transfer from modern, well built small cars to medium cars. Optional side impact airbags would basically pay for themselves. Encouraging both better economy and reduced accident injuries is good for this country.

The next step would be to increase incentives for moving over to hybrid or alternative fuel systems. Hybrids could open the door to plug in technologies, while retaining the flexibility of a quick fill up while on longer trips. FFVs could take advantage of cheap cellulostic ethanol, which might be in the offing over the next five years. Hybrid FFVs could do both; hydrogen is, at best, a solution for our children.

Sadly enough, “American mentality” (Canadian too) implies that things generally are of two types: good and small. This applies to houses and cars first of all. Most of small cars sold in America were and are really crapy. Handful of really good small cars sold here eventually went out of sales due to small volume. However, sky high resale value of CRX, NX2000, or Corrado implies that there are people who value good small cars. Hopefully it will change.

Bring on the minis for use in city streets. Reserve the larger vehicles for areas where the speed limit is over 35 mph. Institute a mandatory car share program in cities and ban everything else. Minimize car use by pedestrianizing inner cities to the maximum extent possible. The goal should be to minimize car use so that the size/technology of vehicles will be increasingly irrelevant in cities.

T:

Join US army.

How about this for a partial solution;
GASOLINE PRICING IN CALIFORNIA; A FIRST PROPOSAL

The basic model of the concept is that of the "baseline energy usage" model currently in place with public utilities in Calif-consumers get the first predetermined amount of their gas and electric utility consumption at a reduced rate, and any energy used over that amount at market rates.With utilities, the amount of baseline rate is largely based upon whether the house/apartment relies solely on electricity for heating purposes. The PC sets the rates and usage allowance, and the utility applies it to the consumer's bill.
With vehicle usage, the vast majority of gas stations now dispense gas thru pumps that are calibrated to read and accept credit cards. California driver's licenses are already credit card size and imprinted with electronic data. Presumably it would not be difficult to either modify the pumps and/or the driver's licenses so that the pump could determine if the license holder who inserts his/her license requesting their baseline usage has already used up their allocation or not for the week or month. Riders could also insert their own licenses to contributed their unused baseline gas for the driver so that car pooling would be encouraged.
Variations in the amount of baseline usage would, and should, reflect the legitimate needs of person's whose work (or other necessary,socially desirable usage) necessitates the unavoidable extra consumption of fuel.Graduated usage rates which promote the steady, but not abrupt switch to more energy efficient vehicles, and their usage, could be implemented.
Monies collected beyond baseline rates could be designated by the legislature,and implemented by a commission of sorts for many uses, including, but not limited to;
Promoting public transportation;
trails, bicycle commuting routes
means of transport which have reduced energy consumption/and/or less pollution
subsidized gas for those in dire need
fixing existing roads
creating more pedestrian and bicycle friendly street crossings and sidewalks

While weight is a factor in fuel mileage horsepower is a greater factor. Look at the Dodge Sprinter which gets 25 mpg while weghing as much as SUVs that get only 12 mpg.

All: RALPH, RALPH, RALPH!!!
Tom: Diesel van=more efficient, but cool.

The Sprinters that get 24 MPG (highway) seem to be diesel powered, from what I've seen. The SUVs that get 13 MPG (city) tend to be gasoline powered. See, for example, the 2006 Chevy Suburban 1500 AWD. That model, by the way, gets 17 MPG on the highway. The traditional diesel advantage (30% better economy, even in engines of similar size, weight and power output) explains most of the difference between the two vehicles, especially on the highway.

The rest of the difference in highway cruising economy, and a good part of the difference in city driving economy actually can be attributed to better design and using an engine with more modest output. But one should be wary of overstating the case for smaller engines.

Smaller engines make a bigger difference in city driving than in highway driving. In highway cruising, the output demanded from the engine is constant and usually fairly modest -- often around 20 hp. Getting that output from a small engine instead of an overlarge one does help economy, but only around 15% in most cases. In the city, since you are making more stops, and consequently making more starts, a larger engine leaves you with greater temptation and ability to leap forward from the line, placing huge horsepower demands on the engine and consuming plenty of gas to meet those demands. Plus, as you accelerate up the gears, you will often be running the engine at inefficient RPMs. With a more measured rate of acceleration -- which a small engine forces you to have -- you get a more efficient start from a traffic light. A hybrid, of course, is an attempt to have the best of both worlds: Quick, efficient, high-torque acceleration from the stop (using electric motors) and very efficient, long range crusing capabilities (using a well-tuned small displacement gasoline motor running only at its most efficient settings). Regenerative breaking helps charge the electric batteries and is icing on the cake, but is not the main draw. Shutdown at traffic lights is also good. But downsizing the motor and, especially, avoiding running it over inefficient acceleration profiles is the main trick.

right, Americans should learn to curb their appetite for the big cars -- and practice good driving habits.