Here are some stubborn realities that we must accept and work around.

First, most Americans have a strong preference for large, roomy vehicles. They feel that these vehicles are safer in an accident and offer conveniences that small cars lack. Second, most American drivers enjoy the feel of extra power in their vehicle so they can pass slower moving vehicles, enter onto to a major road and be able to quickly accelerate to the speed of prevailing traffic.

Detroit has been happy to make big cars/trucks for nearly two decades; these larger vehicles are much more profitable than small vehicles.

But now the larger vehicles are not selling due to the economy. So what could be done? Most big American vehicles will remain on the road, probably for another decade. As I have mentioned in previous columns, why can't Detroit develop new, more fuel efficient engines for these big vehicles (such as a diesel engine to replace a gas/ethanol engine).

Then at special centers, there would be engine transplants to make these vehicles more fuel efficient at a fraction of the cost of a new vehicle. With a new engine, these vehicles would stay on the roads much longer and postpone for years the purchase of an expensive new replacement.

What about hybrid or all electric vehicles? Couldn't we just replace all the gas/diesel engine vehicles with vehicles that use much less gasoline/diesel fuels? Despite being on the market for a number of years, only about 1 percent of all vehicles on U.S. roads are hybrids. Hybrids now make up about 2.5 percent of new car sales.

But what about the plug-in hybrids that use much less gasoline than ordinary hybrids? Wouldn't they be even better? The problem is with the batteries ñ the kind of batteries that power laptop computers. These batteries are great for low power applications and can run a laptop for several hours. But a car needs thousands of times more power than a laptop.

So we need the equivalent of thousands of laptop batteries in each plug in hybrid. How long will these batteries last — as long as a laptop battery (maybe five years)? How expensive will the replacement batteries cost? This is the problem area with the long announced Chevy Volt that General Motors has spent 2 billion dollars to develop. Volt's market date has been pushed to the fall of 2010 due to the long awaited perfection of durable batteries.

Another problem with plug-in hybrids is the need for a sizable increase in off hour electrical capacity. Presently, we rely on coal burning power plants, some natural gas power plants (for peak load), nuclear and hydroelectric dams (some have uncertain future as glaciers melt away).

Where will the added electricity come from for the plug-in hybrids to recharge their batteries every night? This problem is small if a small fraction of the vehicles are plug-in hybrids but will be a major problem if a sizable fraction of vehicles are plug-in hybrids.

There is a problem common to both internal combustion vehicles and electric vehicles; most of the energy for moving the vehicle is used to push dead weight (not the passengers nor their personal belongings). For a regular car that has an engine efficiency of 15 percent (work/energy input), 1 percent is the real efficiency in transporting the driver (usually the only occupant of most vehicles).

An electric car has a higher efficiency, but relies mostly on electricity from coal burning power plants or nuclear plants that operate at about 35 percent efficiency. (Both kinds of plants make about twice as much heat energy as the electrical energy they generate.)

A much better vehicle would be one that's much lighter (less dead weight) so the energy efficiency in carrying a passenger is much higher. There are such vehicles that one sees occasionally on town roads. They are called Motor Scooters. The problem with Motor Scooters is their stability.

Why not make TriScooters? — Scooters with three wheels that would be more stable in bad weather. Use wind shields to protect one's face and floor boards to keep one's feet dry. Another option mentioned in a previous column would be a hybrid air-pedal tricycle that one would compress the air manually, prior to leaving on a short trip.

The added push from compressed air would allow you to go up inclines more easily. These ideas may seem weird, but we need some "out of the box" thinking to revive U.S. car manufacturers. And the above vehicles could be marketed all over the world, increasing American manufacturing and exports.

The moon has now retreated into the late evening sky. By July 14, the moon will be rising after midnight; our companion will appear half full in the southern sky in the early daylight hours.

As the weekend nears, the moon will move into the southeastern dawn sky, to the right and above the brilliant planet Venus.

Bob Doyle's phone number is (301) 687-7799; his email is rdoyle@frostburg.edu