High gasoline costs as well as concerns about the environment have been prompting schools across the country to make their campuses more bike- and pedestrian-friendly. Pressure from parents and students is one big factor in the shift, but another key seems to be a growing awareness about sustainability. A number of colleges are launching bike-sharing programs, some U.S. high schools are aiming to reduce car traffic around their campuses, and plenty of colleges and high schools are looking to expand sidewalks and bike and pedestrian trails to improve car-free access to campus. Some high schools in California are even looking into using bikes for transportation on field trips. Ripon College in Wisconsin launched a free bike program this year for freshman students who agreed not to drive to or park on campus, and some 60 percent of the incoming class took the offer. “Today’s teenagers deserve a lot of credit,” said Mike Martin of the National Association of Pupil Transportation. “They’re socially aware, they’re environmentally conscious. When the price of gasoline takes effect, they’re smart.”