Sometimes, two buses of the same service arrive at the same time with one bus being overcrowded and the other almost empty. Why?
The reason for this is largely due to adverse traffic conditions on the road and other conditions such as road closure, diversions, weather, accidents etc. Indeed, more than 70% of our delays or bunching are due to these reasons. For example, assuming 3 buses started out being 10min apart which was sufficient to cater to the demand along the route (see below).
Bus 1 did not meet any problems and hence, was able to run on schedule. Bus 2 encountered a jam while Bus 3 did not encounter any problems. Hence, the time between Bus 1 and Bus 2 was lengthened, while the time between Bus 2 and Bus 3 was shortened (see below).
By taking more than its share of passengers Bus 2 slowed down as a result, while Bus 3 picked up fewer passengers which caused it to speed up. Bus 2 was thus caught in a vicious cycle that came to a head when the third bus caught up.
To the passenger on the ground, he would have waited 15min and it would seem that Bus 2 was crowded while Bus 3 was relatively empty. In the above situation, adding more buses is not a solution, as the same buses will end up being caught in the jam. More bunching will occur when they do eventually emerge from the traffic slowdown.
We assure our commuters that we try as far as possible to ensure that our buses arrive at regular intervals including adjusting the assignment of buses to suit real time conditions though there is a limit to how changes can be made.
Bus 1 did not meet any problems and hence, was able to run on schedule. Bus 2 encountered a jam while Bus 3 did not encounter any problems. Hence, the time between Bus 1 and Bus 2 was lengthened, while the time between Bus 2 and Bus 3 was shortened (see below).
By taking more than its share of passengers Bus 2 slowed down as a result, while Bus 3 picked up fewer passengers which caused it to speed up. Bus 2 was thus caught in a vicious cycle that came to a head when the third bus caught up.
To the passenger on the ground, he would have waited 15min and it would seem that Bus 2 was crowded while Bus 3 was relatively empty. In the above situation, adding more buses is not a solution, as the same buses will end up being caught in the jam. More bunching will occur when they do eventually emerge from the traffic slowdown.
We assure our commuters that we try as far as possible to ensure that our buses arrive at regular intervals including adjusting the assignment of buses to suit real time conditions though there is a limit to how changes can be made.
We hope commuters can appreciate that traffic conditions on the road can vary. Our schedules, however, can only be planned to meet what is usually the expected traffic condition at the various times of the day. There will be times when the traffic conditions are unusually clear or congested and this often results in buses being too early or late.When traffic conditions are especially clear, our Bus Captains are required to regulate speed if they notice that they are ahead of schedule. This ensures that the Bus Captains keep the arrival times at the bus stops as close to the planned schedule as possible to avoid any disruption like bus bunching.From the perspective of the passengers on board the bus, the journey seems slow but to the passengers waiting at the bus stops along the route, they expect their bus to arrive on time as scheduled. Nonetheless, we will monitor our buses closely and make appropriate adjustments to the running time when necessary.
Why is it that bus services serving my estate do not go to where I want directly but requires me to transfer?
Unfortunately, it is not always possible to have a direct service, as there are literally thousands of possible service combinations and limited number of buses to fulfill this demand.Hence, SBS Transit must trade-off between the needs of an individual and the majority of passengers who stand to benefit from a particular service.Nevertheless, SBS Transit tries to provide as many links as possible to improve the connectivity. In 2005 alone, SBS Transit introduced more than 20 new services in order to serve the needs of our passengers.
Courtesy of SBS Transit
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