Predicting long single decker bus rear swing out impact on infrastructures at bus terminal and road / Muhamad Shaharudin Osmin

In Malaysia, the maximum allowable overall length of vehicle is only 12.19 m (40 ft) (Road Transport Department, 2014). Therefore, only two types of buses available for express bus services which are Single Decker Bus (SDB) or known as high decker bus and Double Decker Bus (DDB). Both bus types will be referred as a 12-m bus in this study. Introducing new bus type which is longer such as Long Single Decker Bus (LSDB) of 15-m for express bus operation may cause safety issues. Longer vehicle normally would cause manoeuvrability issue where its rear swing out may collide with infrastructures or other road users especially at tight intersections, small roundabouts and bus terminals. This research attempted to introduce innovation to the on-road assessment method employed by Sleath et al. (2006) in evaluating LSDB rear swing out impact to infrastructures. Infrastructure discussed in this study referred to any object at bus terminal and road that could collide with LSDB rear (caused by rear swing out) during manoeuvre such as sign post, guardrail, passageway wall at bus terminal etc. A video camera pointing rearward was mounted at the rear of standard length bus to record the projected LSDB rear swing out movement at identified intersections, roundabouts and bus terminals for a round trip from Kuala Lumpur to Kota Bharu, Kelantan. The projected LSDB excessive body at the rear was presented by polyline edited into the video recordings using video editing software. It was found that the developed method is able to assess LSDB rear swing out impact based on predefined severities. The result shows that 12-m bus rear swing out is 100% collision free and LSDB shows 84% collision free, 12% near missed incident and 4% collided incident. In conclusions, LSDB would be generally safe to be operated in Malaysia. Nevertheless, on-road assessment is crucial with attention must be given where limited space available for LSDB to manoeuvre at certain locations.