Abstract:
Median openings are provided to facilitate the U-turn movement of vehicles. Majority
of median openings are uncontrolled and no priority is given for through vehicles.
Uncontrolled median openings result in two kinds of delay. Firstly, the U-turning
vehicles impart delay to the through traffic. At the same time, U-turning vehicles are
also subjected to a certain amount of delay while waiting for suitable gap to merge with
the through traffic stream. The delay experienced by U-turning vehicles are referred to
as service delay while the delay experienced by the approaching through vehicle at the
median opening is termed as median delay. The effect of both U-turning and through
vehicles are incorporated into a single term referred to as area occupancy. The Level of
service (LOS) of U-turn movement at a median opening will be beneficial to analyse
the operational efficiency of the traffic facility. Service delay, median delay and area
occupancy are used to quantify the LOS of the U-turn facility. K- Means clustering
method is adopted in this study to group the parameters to define the LOS. A
comparison among the different LOS classification using the various parameters are
also conducted.
The delay was found to have an exponential increase with rise in vehicular volume with
the two-wheelers experiencing the lowest delay. The models developed from this study
can be used to determine the delay parameters from the vehicular volume obtained from
field data. Clusters were developed for all three parameters that were classified from A
to F. The operational efficiency of various traffic facilities can be analysed by the LOS
determination. A better understanding of such facilities can help to avoid the problems
of congestion and thereby improve the overall quality of service in such facilities
