Paper presented at the 26th Annual Southern African Transport Conference 9 - 12 July 2007 "The challenges of implementing policy?", CSIR International Convention Centre, Pretoria, South Africa.
ABSTRACT: For the calculation of delays and Level of Service at intersections it is important that the correct saturation flow rates for the specific circumstances be used. As a result of a lack of local data practitioners would often use default values from overseas software developers. This can lead to wrong results and inappropriate decisions based thereon.
In a recent study in the vicinity of Stellenbosch the saturation flow rates at a number of intersections were determined. The following situations were observed:
• Turning movement (through or right);
• Gradient (Up and down);
• Number of through lanes (1 and 2); and
• Speed limit (60 and 80 km/h)
From the results it is clear that there are significant differences between the saturation flow rates when the conditions of the movements are different in terms of the above characteristics.
In the paper the background to the study, references to earlier research and the results of this study are given. Recommendations are made as to the most appropriate values to be used under different conditions.