Reducing carbon emissions, especially that of private car use, is an inevitable goal of sustainable transportation policies. This study focuses on i) determination of the current level of CO2 emissions from private cars on the Middle East Technical University (METU) campus and ii) evaluation of the impact of different emission reduction scenarios. Such scenarios were based on hypothetical conditions that can either reduce Vehicle-km-travelled (VKT) or congestion on campus, which are defined as the two major factors governing vehicle emission levels with today's engine technology. To produce a quantitative evaluation, first, as a base case, current private car travel demand was derived from the joint analysis of Radio Frequency Identification (RFID) data and parking lot surveys. In the scenarios, this demand was modified according to the assumptions made. All network assignments were performed using PTV-VISUM software, which produced average speed and number of vehicles on campus roads. The daily assignment was carried out in three parts, as a morning and an evening peak, and an off-peak assignment. Emissions due to congestion were determined separately, as a percentage. The results showed that carbon emissions produced by private cars on METU campus were primarily a function of VKT; thus, could not be reduced by congestion management alone. They could be reduced by 30% if commuters would shift to the metro service that is supported by a strong on-campus shuttle services.