Double-deckers not right fit for S'pore roads?
THEY have been a common sight on Singapore roads for decades but are double-deckers making bus transportation doubly effective?
Lee Der Horng, a transport expert at the National University of Singapore, is urging SBS Transit and SMRT to rethink their use of such buses.
Both transport operators recently announced plans to expand their fleets, with SBS Transit adding 665 buses over the next three years, including 415 double-deck Volvo B9TL Wright buses.
SMRT purchased 573 buses in April. These included 201 ADL double-deckers, a first for the operator.
There are approximately 1,360 SBS Transit double-deckers and three of SMRT's new double-deckers plying the roads now.
But Professor Lee argued: "The existing double-deckers should be put into a museum. The single-deck bus is still the most effective type of bus that should be used in Singapore.
"Singapore's traffic conditions, especially during peak hours, are not suitable for double-deckers, as they have a longer dwelling time at bus stops. This will more likely lead to bus bunching and extend the travelling time for passengers."
Prof Lee, along with researchers from the Future Cities Laboratory, a collaboration between Singapore and Swiss university ETH Zurich, found that double-deckers tend to stand 15 to 20 per cent longer than single-deck buses at each stop.
The study was conducted using anonymous ez-link smart-card data for a week's worth of bus trips. Comparing eight types of buses - including double-deckers, single-deck and bendy buses - on eight routes, the team discovered that the time taken for a passenger to alight from a double-decker is 0.2 second longer than from a single-deck bus.
The study was done based on an equal passenger to passenger ratio, to eliminate the expectation that a double-decker would have a longer dwelling time since it can hold more passengers.
One possible reason is that passengers in the upper deck may tend to wait for the bus to come to a complete stop before moving towards the exit.
Another observation by Prof Lee was that passengers in the upper deck have to wait for passengers in the lower deck to alight before they can do so.
He urged the bus operators to "pay attention to the interior layout of a bus because it does affect the overall performance".
He suggested that they consider other double-decker designs, such as the New Routemaster that is operated by ComfortDelGro's British subsidiary Metroline in London, which has wider boarding and alighting areas, and passengers can hop on and off using a third door at the rear.
They may come with a smaller seating capacity but Prof Lee suggested that the same priority seating practice adopted in trains be replicated in buses so as to ensure that those who really need seats get them.
When My Paper asked SMRT why it chose to purchase double-deckers, it said that different bus types "fulfil different passenger needs".
"Bendy buses are better suited for young children, passengers with disabilities and elderly passengers," it explained.
"Double-deck buses require less space on our roads and serve passengers on the longer trunk routes."
Paul Barter, an adjunct professor at the Lee Kuan Yew School of Public Policy, noted that keeping boarding and alighting times short is key to ensuring quicker bus trips.
"If the problems with boarding and alighting times for our current double-deckers are true, then this should be seriously considered when choosing bus types and designs."