Automakers around the world are currently working overtime to make their vehicles more efficient and cleaner through smaller engines, electric systems and lower weights. As this Active Prediction system from Volkswagen subsidiary Scania shows, secondary technological components can also play a role.

The system fuses GPS and cruise control, allowing the vehicle to predict terrain features of the road ahead. The system predicts the topography ahead and automatically adjusts the vehicle's speed as needed. If you're approaching a downhill, Scania will slow the engine, allowing you to cruise down it. The vehicle will also adjust for ascents.

The Scania system offers the most benefits on undulating terrain, since a flat drive wouldn't require making adjustments to speed. Volkswagen estimates that it can provide up to a 3 percent fuel savings when compared to a regular cruise control system. The company also says that while the system may add a couple minutes to your commute by slowing you down on certain stretches of road, the extra time shouldn't be significant for most commuters (though you might want to shut off the system if you're running late).

Another German auto group - Daimler - introduced a similar system in 2009. Also for trucks, the Predictive Cruise Control system offers the same functionality as Scania's system.

Scania/Volkswagen, is currently positioning the system at the commercial trucking industry, which stands to gain the most money in terms of better fuel economy. It estimates that a 40-tonne tractor trailer traveling around 180,000 kilometers (112,000 miles) a year could save EUR2,200 (US$2,900) and cut more than 4,000 tonnes of CO2 emissions.

Scania plans to equip the Active Prediction system to customer trucks beginning next year. It has the topographic data that it needs to power the system for 95 percent of the road network in western and central Europe.