With the increase in simulation of urban environments for the purpose of planning, modelling vehicular traffic has become important. While empirical evidence on traffic flow is relatively sparse, models representing the same are being increasingly used for planning urban roads and environments. In this paper, a simple explicit model is proposed to approximate the speed versus density of vehicular traffic flow. The model, which uses two parameters, derived from simple measurement on real time traffic data, allows for a prediction of the approximate relationship for congested as well as uncongested vehicular traffic flow. The proposed model is especially useful in conditions where available data is sparse and can be invaluable for the modelling and simulation of urban environments.