In the United States, 14 million people take public transportation each and every day.
That's a lot of buses and trains. Today there's a big push to make all those engines run cleaner and burn fewer fossil fuels.
"There is a limited supply of oil and we have to ensure that we have the ability to satisfy our demand in the future, says Nabil Nasr of the Golisano Institute at R.I.T."
It's a problem capturing the attention of researchers across the country. They hope to meet transportation demands in a way that's more environmentally friendly. The Rochester Institute of Technology is on the cutting edge. It's created a new sustainability institute to look for answers.
"We are looking at different alternative fuels from biodiesel to ethanol to hydrogen as fuel. also fuel cells. We are looking at all the alternative fuel options that we have and looking at when some of these options will be ready for broader use" says Nasr.
Alternative fuels are already being used in buses. But often times, change comes at a higher cost.
"It used to cost almost double to buy a hybrid bus as opposed to a regular diesel bus, but we've seen those prices really drop back. Today a hybrid bus is only about 50% more," says Mark Aesch of RGRTA.
One way to cut down on emissions is to get more people to take public transportation in the first place.
U.S. reliance on foreign oil would decrease 40 percent if one in ten Americans used public transportation daily.
"Clearly there's a comfort level with using your car. If we can make it easier and more technologically friendly to understand how to use public transportation with the high price of gas, it's a wonderful alternative for people," says Aesch.
When considering public transportation, you might also want to consider this:You're 79 times safer riding in a bus than driving your own car.