We attempted to reduce college students' use of their cars with an online intervention. Every other day for 2 weeks, students reported the number of miles they had avoided driving. In a 2 × 2 design, participants received feedback about pollution avoided (e.g., CO2 saved), financial feedback (e.g., gas money saved), or no feedback. A control group did not monitor their driving. Participants in all Web conditions reported driving less than the no-Web control group. In addition, Web participants who received both kinds of feedback reported driving less than did those who received one kind or none. We discuss implications for research on energy conservation and offer an online feedback form to help readers reduce their own driving.