For many travelers today, car rental is an inevitable part of any personal or business trip. When deciding which car rental company to choose, have you ever taken the company's sustainability efforts into consideration?

One major car rental company, Enterprise, recently made an announcement that they plan to spend more than $150 million to build or retrofit sustainable and more energy-efficient buildings. These projects will take place at over 1,000 of their locations nationwide and will go into effect over the next five years.

The plans are part of Enterprise's set of internal sustainable guidelines: the Enterprise Sustainable Construction Protocol (ESCP). The goal of the ESCP is to create a healthy workplace and long-term savings through lower consumption of water and energy. The initiative focuses on seven areas:

1. Materials: Include regionally-produced materials and materials with at least 10% recycled content in construction
2. Energy: Use both interior and exterior energy-efficient controls and systems.
3. Sites: Build on previously developed sites and use materials that reduce the heat of parking lots.
4. Recycling: Reuse fixtures, furniture and equipment (e.g. rental counters, signs, furniture) and recycle construction debris.
5. Water: Install water reclamation systems or low-flow/high-efficient pressure wash systems, use high-efficiency plumbing fixtures, and design efficient landscaping.
6. Air quality: Use Volatile Organic Compounds (VOC) material in paint, carpet, coatings, and adhesives and use Indoor Air Quality (IAQ) plans where appropriate during construction.
7. Process: Develop innovative approaches for each facility and ensure changes positively affect employee satisfaction.

Enterprise is clearly a leader in energy-efficient operations. They opened a location last summer at the O'Hare International Airport which became the rental car industry's first Leadership in Energy and Environmental Design (LEED) Silver-certified independent car rental location. The building was constructed using regional materials and includes a roof system that insulates the building and provides a suitable habitat for native plants. The facility also has a storm water retention system, energy-efficient lighting, and a system for recycling car wash wastewater. The new features have reduced the facility's energy use by 15% and water use by 22%.

Green buildings aren't the only change moving through the car rental industry. Enterprise has been putting together a fleet of energy-efficient cars, and they are the first company to add the new Chevrolet Volt. If you're considering which rental car company to choose on your next trip, keep these companies and fuel-efficient cars in mind.

- Alamo (nationwide) carries the Toyota Prius Hybrid, Toyota Highlander Hybrid, Toyota Camry Hybrid, Nissan Altima Hybrid, Saturn Aura Hybrid, Saturn VUE Hybrid
- Avis (nationwide) offers the Nissan Altima Hybrid, Toyota Prius Hybrid, and Ford Escape Hybrid
- Bio-Beetle (Los Angeles and Maui) carries biodiesel-compatible cars such as the Volkswagen Beetle, Golf and Jetta
- Budget offers the Ford Escape Hybrid, Toyota Prius Hybrid, and Nissan Altima Hybrid
- Enterprise (nationwide) carries the Toyota Prius Hybrid, Toyota Highlander Hybrid, Toyota Camry Hybrid, Nissan Altima Hybrid, Saturn Aura Hybrid, Saturn VUE Hybrid, Ford Escape Hybrid and Chevrolet Volt
- Hertz (nationwide) offers the Ford Fusion, Toyota Prius Hybrid, Toyota Camry Hybrid, Toyota Corolla, Toyota Camry, and Nissan Altima
- National (nationwide) carries the Toyota Prius Hybrid, Toyota Highlander Hybrid, Toyota Camry Hybrid, Nissan Altima Hybrid, Saturn Aura Hybrid, Saturn VUE Hybrid

This list will continue to change as technologies change and as hybrid vehicles increase their share of the market. Keep in mind that these companies don't offer hybrid or fuel-efficient choices at all of their locations, so remember to think ahead when planning your car rental. Not interested in driving a hybrid? Some companies, such as Enterprise, National and Alamo, offer the opportunity to pay an extra charge to offset the carbon dioxide greenhouse gas emissions from your rented vehicle.