With the rapid growth of urban traffic, the gap between traffic demand and supply is increasing by the day, and traffic congestion has become a part of urban Indian life. The following aspects have become important for transportation planners and managers: identification of the frequently congested road sections, estimating their influence on the entire road network, and improving the connectivity and accessibility of the whole road network. Identification of congestion metric is the first step in such endeavour as it would be of help in selecting appropriate remedial measures. This paper presents some insights on how to identify the traffic congestion and establish the congestion thresholds on urban arterials. Stream speed emerges as one of the candidate metrics in identifying congestion on urban arterials. Further, speed studies conducted on an interrupted heterogeneous mix of vehicles plying Delhi urban arterials is also presented.