The exhaust gases from vehicles account for about a quarter of all the carbon dioxide

The exhaust gases from vehicles account for about a quarter of all the carbon dioxide we release. As more people buy cars and take cheap flights, transportation emissions areincreasing, But by designing more efficient cars, buses, and airplanes, and moving toward new kinds of fuel, engineers are helping to clean up the future of travel

Green bus This bus runs on hydrogen instead of gasoline or diesel. Unlike a regular bus, it does not release any greenhouse gas. Iceland was the first country to test hydrogen-powered city buses.

Wonder fuel Hydrogen buses are filled up at special hydrogen fueling stations. The hydrogen is converted directly into electricity and the only exhaust gas is pure water vapor.

Car of the future

Hybrid cars release fewer greenhouse gases than regular cars. This is because some of the time they are powered partly or completely by electricity that the car itself has generated.

Biofuels Though most hybrid cars run on regular unleaded gasoline, drivers in some countries use cleaner alternatives. Biofuels, such as ethanol and biodiesel, are made from plant oils rather than fossil fuels. The amount of carbon that biofuels release when they are burned is much less than regular gasoline.

The number of cars in the world is expected to double over the next 30 years.

Modes of transportation

Different forms of transportation produce different amounts of C02 per person per mile. Cars are the most popular, yet the least efficient way to travel. Although buses and airplanes use more fuel than cars, they can carry many people at once, which means they release less carbon per passenger. Almost no C0₂ is released by cycling or walking.

Dual engine  Hybrid cars have both a regular gas engine and an electric generator. The generator is run off batteries that never need recharging, because they recycle energy made by the wheels when the car is coasting and braking. 

Slick wheels This hybrid car’s wheels fit snugly into the arches around them, making the wheels more streamlined. Low-resistance tires decrease the amount of drag from the road. This helps the car to save energy and use less fuel.