The problem of increasing oil prices in the market and the bad effect of fuels distilled from crude oil in the environment is a big challenge for car rental companies. Many car rental companies now respond to the new demand of the market, the need for environmentally friendly cars. This demand grows because of the pressing issue on global warming. They not only address the issue on air pollution but they also promote the use of energy efficient cars to make use of our resources wisely.

The Enterprise Rent-A-Car which is a car rental company funded in 1957. In Atlanta, they had started their "Green Branches" at four locations in the country. Sixty percent of the cars available in their Green Branches are hybrids and fuel-efficient cars. This shows that the company promotes the use of environment friendly vehicles using alternative sources of energy. In each branches of the Enterprise Rent-A-Car company, there are at least 30 percent fuel-efficient vehicles and at least 30 percent gas or electric hybrid vehicles available for rental. The Buckhead Area Enterprise Rent-A-Car, which is the largest branch of the company, offers 50 hybrid vehicles for rental. The other three branches in Atlanta are Downtown Area Enterprise Rent-A-Car, Dunwoody Area Enterprise Rent-A-Car, and Emory Area Enterprise Rent-A-Car. Now, there are about 160 rental branches in Atlanta. The company now operates Car Sales, Commercial Truck Rentals and Fleet Management Division throughout the Atlanta market.

In the past year, Enterprise continued installing Flex Fuel branches near E85 fueling stations in the US offering flex-fuel vehicles which are run by E85. The company is committed to promote environmental awareness to its consumers and other people. They want people to recognize the E85 or Flex Fuel as an alternative to their conventional petroleum fueled cars. They also promote and funds research for other alternative fuels and energy source which are derived from renewable sources. They believe that they are in the right track and their approach will eventually sustain their company.

In UK, Car Hire UK offers environment friendly and fuel efficient range of vehicles to rent. They said that they understand the importance of taking care of the environment and their role as a good steward of it. They offer the latest range of environment friendly vehicles out in the market which make use low carbon emission technology and emit the lowest amount of carbon dioxide in the atmosphere. They are working with the major manufacturers of greenest cars and offer those cars in relatively low rates to encourage people to use the green cars and be aware of what they could do helping the environment in using those vehicles. They offer incentives in renting green vehicles to promote it more to their consumers. They want people to understand that our increasing dependence on oil drilled from the earth is not good for the sustainability of the earth. That is why they aim to offer the entire available green rental vehicle in their branches making them more cost effective than the usual vehicles.