Innovations in car transport include:

• Fuel injection, turbo engines, power to weight ratio, tyre variants, engine management systems, ABS breaks, regenerative braking and reduction in drive train losses.

Environmental Impacts

• Improved power to weight ratios have led to greater fuel efficiency (less consumption).
• This has resulted from innovations in the strength of aluminium alloys and the use of carbon fibre composite components both of which make the car lighter.
• Cars with more aerodynamic shapes are also being routinely produced, which reduces drag.
• Therefore, modern cars that are more aerodynamically designed and built with lighter materials, have considerably less drag, and thus \(\ce{CO2}\) emissions are reduced.

Innovations in rail transport include:

• Turbo driven diesel engines, magnetic levitation braking, disc brakes, electric trains with AC versus DC motors and efficient track alignment.

Environmental Impacts

• The use of AC motors in the drive train, rather than DC, has been the most positive modern innovation in rail transport.
• VVVF (variable voltage variable frequency) drives, control the voltage and torque on modern AC machines, creating greater efficiencies, as DC machines lose electricity as heat.
• Regenerative braking can be employed by AC machines as a train descends or slows down.
• These improved efficiencies result in less diesel fuel on country trains and less electricity on city trains, leading to a reduction in \(\ce{CO2}\) emissions.

Innovations in air transport include:

• The use of composites to create more aerodynamic shapes and reduced weight, improved efficiency in turbofans, reduced drag and the removal of rivet-induced turbulence through the use of adhesives.

Environmental Impacts

• Fuel efficiency is greatly improved through the use of modern turbofan engines that optimise the entrainment of by bypass air, which produces 90% of the total thrust of the engine.
• The use of flow control devices and winglets on wings, minimise wing tip vortices, improving lift and reducing drag.
• Efficiency is therefore improved leading to reduced fuel consumption and a consequent reductions in \(\ce{CO2}\) emissions.

Answers should discuss one of the following:

Electric powered cars

• Electric powered cars do not need heavy engine components to propel them as their energy comes from an electric source. There are also fewer moving parts resulting in a net decrease in weight.
• Lighter engineering materials further contribute to the decreased weight, which improves fuel efficiency and lowers `\text{CO}_2` emissions.
• Furthermore, combustion engines themselves produce large volumes of `\text{CO}_2`, hence their removal greatly decreases emissions.

Electric powered bikes

• Place lower energy demands on a rider, which decreases the `\text{CO}_2` emissions from the cyclist.
• Battery technology increases the bike’s range and decreases its emissions, enabling long distance travel without negative environmental impacts.

Successful answers should discuss one of the following:

• Lighter/more streamlined cars are generally more fuel efficient. This has been achieved through improved manufacturing methods and improved materials (ie replacing steel bumpers with lighter polymers).
• Improved materials technology used to produce aluminium engine blocks instead of cast iron to decrease weight.
• Mathematical modelling to increase aerodynamics of a car.
• Hybrid cars and regenerative braking.
• Shift towards fuel injection and higher compression ratio.
• Cruise control maintains better average fuel economy.
• Improved efficient gearboxes and differentials with low friction and torque.
• Improvements to lubrication technology to reduce internal friction.