One hundred years after its invention, the car has become a common sight in most cities in the world. But did you know that the conventional car powered by the internal combustion engine is a very inefficient vehicle? Only 20 percent of the fuel is used to turn the wheels, the rest is wasted, lost mainly in the engine and the exhaust. And that's not the worst part: for each litre of petrol burned by an engine, three kilograms of air pollution that contain harmful gasses are released into the air. And that's just from one car!

Which is why it comes as a relief that car makers are putting their brains (and money) towards producing a greener vehicle. Toyota launched the Prius, a hybrid car in Singapore in May 2006, while the Honda Civic Hybrid is a similar green car that was launched in June 2006.

Hybrid cars consume only half of the average amount of petrol required and emits 80 percent less in exhaust with significantly lower carbon dioxide and nitrogen oxide levels. It is powered by a combination of petrol and electricity. As the car is moving off or at low speeds – that is, when the engine is least efficient – an electric motor starts up the engine. Once the car gets moving to higher speeds, the petrol motor steps in, running at its optimal. During deceleration or braking, electricity is regenerated and the battery recharged.

Because of this, the hybrid car is perfect for city-driving conditions as it doubles the mileage. For example, the Toyota Prius can achieve as much as 23.3km per litre of petrol compared to between 10 to 12km per litre for an equivalent conventional car.

The US is already boasting a huge following for hybrid cars. More than 100,000 cars are sold each year, with a waiting time of up to six months. In fact, in 2005 alone, 235,000 hybrid vehicles were sold around the world.

In Singapore, "green" cars have been slow on the take-up mainly due to higher costs. This is despite the fact that the government had reduced the cost difference by introducing the Green Vehicle Rebate in 2001.

There are now, as at end June 2006, more than 90 hybrid cars on the roads in Singapore. These include those driven under a car-sharing scheme operated by Honda Diraac. Though this is a small number compared to the total number of cars on the road at the moment, it is a start. Given the advancement of engine evolution, prices of hybrid cars should continue to decrease. And with rising fuel prices, coupled with an increase in informed and responsible consumers, hybrid cars may well be a common sight on the roads in the near future.