We examine the impacts of a sustainable urban transport initiative, the first Bus Rapid Transit System launched in Lahore, Pakistan in year 2013. We measure the socio-economic and environmental impacts of the BRT using a questionnaire-based survey that collected information on customers’ travel purpose, travel frequency, travel time, mode access, previous travel mode choices (pre-BRT) and travel mode choices at present. We estimate that, on average, a BRT passenger saves about 46 minutes per day on a single trip. However, the modal shift from personal automobiles to the BRT system is found to be only 4 percent, i.e., significantly less than the shift found in other worldwide BRT systems. Moreover, we estimate the reduction in the number of private vehicles on roads, total distance travelled in km and associated travelling costs and, subsequently, the reduction in the carbon emissions. We conclude that the Lahore BRT transit system needs to be expanded to other parts of the city.