Relationship of Mainstream Traffic Operating Speed Towards Percentage of Heavy Vehicle During Entering and Exiting Meru Tunnel: A Case Study Meru-Menora Tunnel

This study was conducted to compare the 85th percentile or can be known as operating speed of entering and exiting the Meru Tunnel with the presence of heavy vehicle. The study focusses on the effect of percentage of heavy vehicle in the mainstream traffic towards the behaviour and speed on the surrounding vehicle. The case study location was located at Meru-Menora Tunnel, Perak on the southbound which is a two-lane highway with a design standard of mountainous terrain rural expressway R6 by using the radar and laser gun for the spot speed study analysis. The study recorded the spot speed study data with the classification of each vehicle for further analysis at four different location which is at 50 m approaching Meru Tunnel, entering Meru Tunnel, exiting Meru Tunnel, and 50 m leaving Meru Tunnel. The obtained data was analysed by using statistical software called Minitab 21 and Microsoft Excel software. From the analysis, regression analysis was done for Time Mean Speed exiting Meru Tunnel for each lane which is lane 1 and lane 2. Two regression model was produced from the Minitab software which shows the relationship of percentage of heavy vehicle towards the entering and exiting traffic speed from Meru Tunnel. The results show that with presence of higher percentage of heavy vehicle in the mainstream traffic, the overall traffic speed was reduced during entering and exiting Meru Tunnel. The study also shows the effect of tunnelling towards the surrounding traffic speed where road tunnels reduce the speed of traffic due to the confine space in the tunnel and a limited vision in the tunnel affecting the driving behaviour of the traffic.