7: TripAlyzer

More and more vehicles are coming equipped with onboard data centers that measure everything from thevehicle's fuel efficiency to average speed. If you don't happen to have these features in your vehicle, fear not. TripAlyzer, developed by Surich Technologies Inc., is for iPhone owners that want to get from point A to point B as quickly (and efficiently) as possible.

At just $5.99, TripAlyzer is more expensive than some of the other iPhone apps. However, once downloaded, iPhone users can enter and save all vehicle information and begin tracking their driving habits. TripAlyzer users the same technology as the GPS systems for the iPhone -- cell tower or WiFi triangulation -- and is designed to analyze your driving habits to calculate how efficiently you use your fuel. For those of you already hypermiling, TripAlyzer will let you know how well you're doing with your eco-friendly driving skills. After each trip, TripAlyzer can also give you a bottom line cost of how much you spent.

By simply entering your odometer reading, TripAlyzer will track the distance of your trip and provide you with valuable information that you can store for future use. Since the intent of TripAlyzer is to help users drive more efficiently and cut down on CO2 emissions at the same time, the app also reminds you of service intervals and can even let you know what your carbon footprint looks like.

6: INRIX Traffic

Even if your car has a GPS with built-in traffic information, you might find that the INRIX Traffic app can help you plan your route in ways that your GPS can't. Of course, to access the more advanced route-planning services that the INRIX Traffic app offers, you'll need to pay $24.99 to upgrade to INRIX Traffic premium, but even the basic free app gives you a wealth of traffic information for your daily commute or just for a trip across town.

Here are some of the things that INRIX Traffic can do even without the upgrade:

• Incidents: A list of traffic events, updated via the Internet, which may affect the route you plan to take. These include accidents, crowds at major sporting events, convention traffic and other tie-ups reported by members of the INRIX Traffic community.
• Comparative Traffic: A map of the local area with traffic density marked out in color-coded lines that tell you which routes have light traffic and which routes are bumper to bumper.
• Predictions: A timeline that allows you to project traffic for the 15-minute interval during which you plan to be traveling.

There are several other traffic apps available for the iPhone, but INRIX Traffic has a solid community of users reporting conditions and, if you use the app, you join that community too. If what you see on the road doesn't agree with what you see on the app, you can report the mistake with the click of a single on-screen button.