Green as I am, I’m also a techie who loves cool apps. Tomorrow’s cars will not only be ultra-clean, but they’ll also use advances in downsized and affordable technology to offer a range of useful features. So think small, think environmentally friendly, but also think high-tech.

Small cars (and diesels, too). Cars will get smaller, whatever happens to fuel prices. Two of the big sales success stories in recent years have been the Smart car and the Mini. I think the Ford Fiesta and the Fiat 500 will also do well in the U.S. Right now, Americans are moving from big SUVs to smaller crossovers, and the trend will continue. Soon we’ll be importing the microcars that clog European and Japanese roads. Take a look at the tiny Toyota iQ, the smallest four-passenger car in the world, with a 1.4-liter turbodiesel engine and as much as 52.3 mpg. Its minuscule rivals, in Europe, are often diesels such as the VW Polo Bluemotion 1.4 TDI (61 mpg). Diesels are definitely worth a second look (particularly because we have the cleanest low-sulfur diesel fuel in the world).

Stereo systems will further merge with home electronics. The Ford Sync system was a pioneer in allowing consumers to hook up not only their iPods, but also USB-enabled hard drives — and have the whole thing read by the head end. That’s going to go global. Now almost every car has at least a mini-in for a ‘Pod, and even lower-end cars are getting advanced connectivity. Larry Burns, the retiring fuel cell and EV guru at General Motors, told me yesterday that connectivity for cars is going to be the next big frontier. Owning a car used to be the ultimate freedom, but for kids like his teenaged daughters, it’s all about iPods, cell phones and PDAs.

The future is electric. My previous post profiled eight EV start-ups, many of them in Silicon Valley and many headed by former computer guys. Some are producing plug-in hybrids, and some battery cars, but batteries and some form of electric plug are what they have in common. That’s why the federal government is pouring $2 billion of stimulus funding into building battery factories in the U.S. — otherwise we lose all this business to Asia.

Passive safety is on the way. The Toyota Prius — the most fuel-efficient hybrid on the road — is also a leader in keeping its passengers safe. The second-generation Prius earned very high ratings in government crash testing, and the third-gen bristles with cool high-tech safety stuff. Among the optional features are Lane Keep Assist and Intelligent Parking. The first one uses cameras to make sure you stay in your lane, and the second can guide your car into a parallel parking space. There are also seatbelt pre-tensioners, and stability control. In Sweden, I took part in a demonstration of an innovative system that sensed an upcoming impact and actually slowed the car to a crawl by applying the brakes. Another system can read eye movements meaning the driver’s about to fall asleep. The Europeans are exploring — and mandating — pedestrian safety devices for cars. Expect to see a whole lot more of this kind of preventive safety measure on cars and trucks.

Navigation systems will become intelligent (and maybe gain “awareness,” too). The first in-car CD-based navigation systems were so novel that the maps and cool voices giving directions was more than enough. GM’s OnStar added such great features as finding a lost car in a parking lot and accident assistance. But tomorrow’s systems will do more, including advising you of traffic congestion ahead, steering you around accidents, giving you fast-breaking weather tips, pointing you toward Mongolian restaurants in your area, providing movie times and making reservations, and much more. The latest Magellan Maestro unit includes a number of these features, including “SmartDetour,” which prompts you to route around congestion, live traffic updates, and even a 3D-view feature. According to CNET, “Experts say upcoming navigation systems will be more active, thanks to cellular or satellite links to real-time weather, road or traffic information that can be displayed over location maps. Satellite connections are typically more robust than cellular ones in remote locations.” As a VW exec explains it, “Next-generation navigation systems will have connectivity and map a certain state of the road, whether it’s closed or snowy, or even traffic-heavy, to give you an understanding of conditions.” A safe road could be green, and an icy one red, for example.

Here's a video on what the next Ford/Sirius stereo-nav system can offer:

My navigation system can't wait to see what's around the corner. Neither can I.

Jim Motavalli ( @jmotavalli ) writes about cars, technology and the environmental world to anyone curious enough to ask.

Cool cars: Five trends to watch
Tomorrow's cars will be cleaner and greener, but they will also bristle with high-tech features to make driving easier and safer.