Joint News Release by the Land Transport Authority, SBST & SMRT - Bus Service Reliability Framework

News Releases 24 Jan 2014 Excess Wait Time (EWT) bus services Bus Service Reliability Framework (BSRF)

To improve bus regularity, reduce bus bunching
22 bus services under BSRF starting from February 2014 

  1. The Land Transport Authority (LTA) will implement the Bus Service Reliability Framework (BSRF) with 22 bus services on a two-year trial to improve en-route bus regularity, and reduce instances of bus bunching and prolonged waiting times.
  2. Seven SMRT bus services - 176, 184, 188, 302, 858, 901 and 911 - will be placed on the BSRF from 3 February 2014, followed by eight SBS Transit bus services 3, 17, 39, 52, 228, 241, 242 and 325 by March 2014[1]. The remaining seven bus services will be implemented by June this year. These 22 bus services include a mix of long and short trunk services as well as feeder services.

Bus Service Reliability Framework

  1. The BSRF assesses the regularity of a bus service using the concept of Excess Wait Time (EWT). Measured across all the trips for a single bus service, and at several bus stops, EWT is the average additional waiting time actually experienced by commuters at bus stops, compared to the expected waiting time if the buses arrived at regular intervals. For example, if a bus service arrives perfectly regularly, the EWT will be 0 minute. However, if there is bus bunching which results in prolonged waits for the subsequent bus, the EWT will increase.
  2. EWT will be measured during both peak and off-peak hours from Mondays to Fridays, excluding Public Holidays. Each bus service will have its own existing “baseline” EWT depending on the current performance and the characteristics of the route. Typically, a long trunk route will have a higher existing “baseline” EWT. The EWT of a particular bus service can be improved if bus arrivals at each bus stop become more regular and more evenly spaced. A lower EWT means fewer instances of bus bunching and as a result, commuters should generally experience more regular waiting times and greater ease in boarding as the passenger load will be spread more evenly across the various bus trips.

Improving bus reliability

  1. Under the BSRF, bus operators are given incentives to reduce their EWTs. Reducing EWTs is operationally challenging and additional resources will be required, such as hiring more service controllers to manage bus services and having standby buses to inject mid-route if there are delays to buses which are already en-route.
  2. Incentives are calibrated in accordance with the efforts and operational costs involved in improving the reliability of the services. Operators are rewarded only when they achieve improvements in bus service regularity, and are penalised if the service is not so. Similar incentive-penalty schemes have been practised in other cities. LTA modelled the BSRF, including the relative quanta of incentives and penalties, after London which has successfully implemented a similar programme for more than 12 years now.
  3. To allow bus operators to adjust to the new framework, there will be a transition period from 3 February until 31 May 2014 when EWTs will be monitored but no incentives or penalties will be applied.
  4. Bus controllers can regulate bus speeds by having the bus slow down or hold at bus stops for short intervals, generally no more than about a minute or so and only if it does not cause any obstruction. Commuter safety will not be compromised. All buses, including those under the BSRF, are already required to adhere to speed limits on the roads. All buses are also installed with speed limiters that prevent them from going beyond 60km/h.
  5. The BSRF trial will allow LTA to better understand bus reliability improvements that can be made on different types of routes, as well as the BSRF’s effectiveness to get bus operators to improve service reliability, complemented by other regulatory measures such as more strictly enforcing bus lanes and enhancing bus priority schemes and measures.

Annex A: Presentation on BSRF Trial

[1] Services 17, 52, 228 and 242 will start from 28 February 2014 and Services 3, 39, 241 and 325 will start from 24 March 2014.


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