Centre for Science and Environment has carried out this simple and indicative exercise to assess the impact of congestion on travel time and traffic speed on Delhi’s major arterial roads which have been specially designed to give priority and primacy to improve speed of vehicular movement. This assessment has used the daily real time information of Google Maps for different arterial roads during the month of June in Delhi to calculate average traffic speed during different hours of the day on the roads. There is a rider -- June is not the most representative month as educational institutions remain closed.