Potential future car technologies include varied energy sources and materials, which are being developed in order to make automobile

Automobile

An automobile, autocar, motor car or car is a wheeled motor vehicle used for transporting passengers, which also carries its own engine or motor...

s more more energy efficient

Efficient energy use

Efficient energy use, sometimes simply called energy efficiency, is the goal of efforts to reduce the amount of energy required to provide products and services. For example, insulating a home allows a building to use less heating and cooling energy to achieve and maintain a comfortable temperature...

 with and reduced regulated emissions. Cars are being developed in many different ways.

With rising gas prices, now the future of cars is leaning towards fuel efficiency, and energy-savers, hybrid vehicle

Hybrid vehicle

A hybrid vehicle is a vehicle that uses two or more distinct power sources to move the vehicle. The term most commonly refers to hybrid electric vehicles , which combine an internal combustion engine and one or more electric motors.-Power:...

s, battery electric vehicle

Electric vehicle

An electric vehicle , also referred to as an electric drive vehicle, uses one or more electric motors or traction motors for propulsion...

s and fuel-cell vehicles.

• Platoons
  Platoon (automobile)
  Grouping vehicles into platoons is a method of increasing the capacity of roads. An automated highway system is a proposed technology for doing this....
  
   of cars that are controlled by the lead car
• Vehicle infrastructure integration
  Vehicle infrastructure integration
  Vehicle Infrastructure Integration is an initiative fostering research and applications development for a series of technologies directly linking road vehicles to their physical surroundings, first and foremost in order to improve road safety...
  
  
• Driverless car
  Driverless car
  An autonomous car, also known as robotic or informally as driverless, is an autonomous vehicle capable of fulfilling the human transportation capabilities of a traditional car. As an autonomous vehicle, it is capable of sensing its environment and navigating on its own...
  
  

One major problem in developing cleaner, energy efficient automobiles is the source of power to drive the engine.