Purely electric cars have not worked. They must be recharged too often, and recharging takes too long. The battery packs are so large and heavy that they severely harm the performance and functionality of the vehicle.

For these reasons, auto makers are now shifting their attention from all-electric vehicles to "hybrids," which use both an internal combustion (gasoline or diesel) engine and an electric motor. This technology is not entirely new. The diesel-electric locomotives that have powered trains for decades use one form of hybrid powertrain. In these locomotives, a diesel engine spins an electric generator that powers electric motors that drive the wheels. Since the diesel engine does not directly drive the wheels, but only works indirectly through the electric motors, this is called a "series" hybrid.

This type of hybrid is very efficient because the diesel engine can be kept in its most efficient operating range all the time. The downsides for automotive use are that this type of hybrid is very heavy, because the electric motors must be large enough to provide all of the power to the wheels, and it feels much different than a conventional powertrain to drive.

For these reasons, for automotive use a "parallel" hybrid seems to be the favored design, at least for now. In a parallel hybrid, both the internal combustion engine and an electric motor drive the wheels. In general, parallel hybrids also contain the series layout: the engine also turns a generator, which charges a relatively small set of batteries, which powers one or more electric motors. The benefit of this is that you never have to plug the vehicle into an electrical outlet. You just refuel it like a conventional vehicle.

Why make a hybrid at all? Compared to a regular automobile, they promise to be both more fuel efficient and more ecologically sound, especially in city driving. There are at least two reasons for this. First, regenerative braking can be used. When the driver hits the brakes, the vehicle can be slowed down at least in part by using the wheels to turn an electric generator that charges the batteries. While not as powerful as brakes, the generator when in operation does slow the vehicle considerably. If more powerful braking is needed than the generator can provide, then conventional brakes are called into use. In this manner, at least some of the energy earlier used to accelerate the vehicle is recaptured. The second benefit to fuel economy and emissions is that in low-speed driving the engine can remain off, so that only the electric motor is used. Because both of these factors are most used in slow, stop-and-go city driving, hybrids have their largest benefits in this scenario.

While Honda's Insight was the first hybrid sold in the U.S., Toyota actually introduced the first one worldwide. The Prius went on sale in Japan a few years ago. It was not sold in the U.S. initially because market research indicated it was far too weak for American drivers. Also, Japanese do far more stop-and-go city driving than most Americans (the average driving speed in Tokyo is somewhere around 10 mph). Now that Toyota has developed a more powerful version of the engine, 70 vs. 57 horsepower, the vehicle has gone on sale in the U.S.

So, what is the future like? To find out, I test drove a Prius. Because it has a rear seat and does not have a manual transmission, it makes more sense for most people than the Insight. Also, the technology in the Prius is more sophisticated than that in the Insight, and makes more use of the electrical half of the powertrain.

The Prius looks more like a normal car than the Insight, since it doesn’t employ a teardrop shape, rear wheel spats, or any other highly aerodynamic devices aside from a small spoiler on the trunk lid. Well, normal aside from its proportions. Much like the Echo, but a bit less so, this is a short, narrow, very tall car. At 170 inches in length, the Prius is nearly half a foot shorter than a Civic or Corolla. Its width of 67 inches is comparable. But its height of 58 inches makes it over three inches taller than those cars. The sheetmetal has the numerous creases and cuts of which Toyota is fond lately. Overall, it looks pleasant enough, like a tall, somewhat appliance-like compact with just a bit of edge to it. Less bland than a Corolla or Civic, and much less ugly than an Echo.

This height translates into a surprisingly roomy interior. Everyone front and rear has more room than you’d expect in a compact. All of the seats are quite a bit higher than those in a typical car. Because the shifter is on the dash, only a low storage console divides the two front seats. Expansive glass all around provides great visibility. Due to these features the Prius feels more than a bit like a minivan from the driver’s seat, if a small one. It certainly feels like no other car I’ve driven, even the Echo. Because the car is narrow, three in the back would be a bit tight, though. The seats are upholstered in standard compact car gray velour. Nothing fancy, yet also nothing offensive, and comfortable enough.

The gear selector sticks out of the dash next to the steering wheel at a very unusual angle. To operate it, you pull it down much like the handle on a slot machine. The rest of the dash is just about as unusual as the gear selector. All instrumentation is in the center of the dash. The digital speedometer and fuel gauge are mounted in a slot at the top of the dash. Below them rests the most interesting instrument I have ever seen in a car: a flat panel display that constantly displays the energy flows among the engine, motor, batteries, and wheels. I found myself looking at this screen at least as much as I looked at the road. Very interesting. I would assume it’s there so you can learn how your inputs to the brakes and accelerator affect the powertrain, but it’s also quite good for entertainment value. Below this nifty screen lie fairly conventional stereo and climate controls.

Generally the car seems of good if not excellent quality. The doors are the major exception. Because they are very tall and flat to provide the maximum amount of interior room, they have a light, tinny, weak feeling to them when opened and closed. Just a little pressure from your palm is enough to push in the sheetmetal. I expect all of those creases are intended to add strength to the door panels, but more is needed.

Cargo space is both good and bad. Plenty of storage is available in numerous places throughout the interior. The trunk though not especially large at 12 cubic feet is similar in size to those in the Civic and Corolla. Its shape is usefully regular. The bad news is that the rear seat does not fold down like it does in most compacts, so the trunk is not expandable. I personally use this feature a lot in my cars. It seems Toyota had to put some of the powertrain componentry between the rear seat and the trunk.

The powertrain of the Prius is highly sophisticated. The 1.5 liter engine is designed for maximum economy and minimum emissions. For efficiency reasons it redlines at 4500 RPM, which is also where the power peak is. Because the redline is so low, the internal parts of the engine do not have to be very sturdy, and thus the engine is very light in weight. A computer splits the engine’s effort between turning the wheels and powering a generator. The computer also determines how effort is split between the engine and motor in turning the wheels. At slow speeds, only the electric motor is on, unless the batteries have already been depleted, in which case the engine is automatically started to power the generator and turn the wheels. Reverse is always electric only, since the engine’s transmission lacks a reverse gear. For those who have never driven an electric car, electric-only operation is strangely silent. Under heavy acceleration, the computer will direct the engine and motor to both give all they have to turning the wheels. This isn’t a whole lot: this car takes a bit over 12 seconds to get to 60 from what I have read. At least this is two seconds quicker than the Japanese-market Prius! If the batteries are depleted, say by a long uphill grade, acceleration gets much weaker. In a Car & Driver test of the Japanese version 0-60 without the electric motor took over 20 seconds. So I would not recommend this car for people who live in the mountains.

The engine’s transmission does not have gears in the standard sense. Instead, it is a continuously variable unit that allows a virtually infinite number of ratios between two extremes, so the computer can keep the engine at the optimal RPM at all times. This type of transmission has only been available in the U.S. on the defunct Subaru Justy and the Honda Civic to date, but will be more prevalent in the future. In this way also Toyota is selling the future in the Prius.

The gear selector requires some knowledge to use apart from its unusual design. The choices are PRNDB. We all know what D is, but what’s B? It took me a little bit of research to figure this out. In D, regenerative braking only occurs when the brake pedal is used. In B, regenerative braking is used whenever the driver lifts his or her foot off of the accelerator. This is useful for coasting down long grades, when engine braking is desirable and might as well be used to generate energy. But in most situations the use of B will harm both performance and fuel economy because it will create more work for the engine.

Toyota understands than many people would worry about the reliability of all of this leading-edge componentry. So an eight year, 100,000 mile powertrain warranty is standard.

So what is all of this technology like to drive? Less satisfying than one might hope, but much better than I expected. The response from the powertrain is generally sufficient, but never exhilarating. Responses are often a bit slow, as if the computer takes a little while to make its computations and tell the various components what to do. That said, the operation of everything is surprisingly seamless given the level of complexity involved. There is never a bump or a jolt to be felt. You do not distinctly feel tasks being juggled between the engine and motor, or between the generator and brakes. If you didn’t know what you were driving, you might not notice anything at all. Turning on the A/C resulted in a very noticeable decrease in performance, no surprise given the weakness of the powertrain. However, as long as you don’t expect strong acceleration, you’ll be satisfied with the powertrain’s performance in typical around-town driving.

The most noticeable aspect of all this switching about is that the engine automatically turns off when you come to a stop. This way the car uses no fuel when idling. No need to restart it. When you hit the accelerator again with enough force to require the engine, it will automatically restart. You don’t feel or hear much when it restarts, either, because the always-engaged generator doubles as the starter and various other neat tricks. Very slick.

The brake application is not quite as slick. The brakes are quite non-linear in feel. Push them a little, and you get just a little response since only regenerative braking is engaged. Push harder and the conventional brakes kick in to help out with a noticeable impact. Twice the effort on your part often leads to more than twice the braking force. It’s not unsettling, just a bit weird in feel. I suspect you get used to it after a while.

Chassis performance is a mixed bag. The ride is quite good despite the shortish 100 inch wheelbase. But this seems to be due to an overly soft suspension, which combines with the height of the car and driving position to produce a great deal of lean in turns. Even more than when standing still, under way this car feels like a small minivan. The steering doesn’t help. It communicates very little road feel and has a strange elastic quality to it. As with the engine, steer the Prius conservatively around town and you’ll be satisfied. Push it, and you’ll quickly run into its limits.

The Prius rides quietly for a compact. Part of the reason is that the engine never makes much noise because it is never spinning very fast. But road and wind noise are also quite reasonable.

Though the Prius is certain to appeal to some people because of its leading-edge technology alone, this car is supposed to be about fuel efficiency. So how well does it do? The EPA ratings are 52 City and 45 Highway. It is unusual to see a Highway rating that is lower than a City rating. The reason for this is that on the highway regenerative braking is not used much so the gasoline engine must the most of the work.

Most reviews I have read reported substantially lower fuel economy, about 35 MPG. I suspect this is because how you drive the Prius will greatly affect its fuel economy. To get the best fuel economy, you must make maximum use of its regenerative braking and electric motor. What this means is that you should take as little pedal effort and thus as much space to slow down the car as possible. It also means that whenever you are going up and down hills you should shift into B, then shift back into D on flatter terrain. Less force on the accelerator, so the electric motor can do a lot of the work, also helps. Other techniques would undoubtedly boost economy further. Just study that screen while driving (but don’t hit anything)! Most Americans, of course, are going to drive how they want to drive. The Prius is probably not the car for them.

For people who are interesting in a highly economical, highly efficient, fairly functional compact, the Prius is worth a look. Performance and handling are not very good, and border on the weird in driving feel, but they aren’t unpleasant and will do for around-town driving. And the price, at $20,000, is quite reasonable. It’s not much more than a conventional compact. Toyota is losing buckets of money on each Prius sold. It is writing this loss off as a learning exercise. Hybrids represent the future of automotive design, and Toyota plans to have the best hybrid technology once they do become the dominant design. If you are also willing to see a car as a learning exercise, if driving the future appeals to you, then certainly check out the Prius. Just don’t expect to autocross it.

First-generation Prius Reliability

People often email me asking about the reliability of the cars and trucks they are considering. They tend to be especially concerned when the car in question is a hybrid. Existing sources of reliability information just aren't helpful enough.

In response, my website, truedelta.com, will more clearly identify what difference it will make if you buy a Prius rather than something else with fewer high-tech bits by providing "times in the shop" and "days in the shop" stats (among others). Those who help provide the data--which will require just a few minutes a year--will earn free access to the site's reliability information. To encourage participation, this access will otherwise cost $24.95.

For the details, and to sign up, visit www.truedelta.com.