By how much will Singapore's Bus Service Reliability Framework improve service punctuality?
The jury is still out, but observers agree that the first incentive-and-penalty scheme of its kind here is a step in the right direction.
A two-year pilot scheme will begin next month, which Public Transport Council chairman Gerard Ee called "work in progress".
"It's a start point," he said. "We have to give it time to work. And everyone must play a part - including motorists giving way to buses, or playing cat-and-mouse with enforcement officers. But quite logically, a carrot-and-stick approach should help."
The Land Transport Authority said the scheme seeks to minimise excess waiting time (EWT) - the difference between actual and scheduled wait times.
"An EWT score of one minute is considered good, while an EWT score of two minutes is satisfactory," it said.
"As the EWT score is an average... it is possible that for a single bus stop on a specific day, the actual waiting time of commuters deviates more significantly than the EWT score of that service."
Mr Tan Pang Soon, a regular bus commuter, said: "The framework is good as it tries to penalise buses that are not on time or worse, too early.
"Buses being early are the main cause of erratic bus waiting time."
The 24-year-old university student added that the 15 services selected to be measured from next month "cover a good range with feeder, trunk and loop services".
In the pilot, an operator stands to gain up to $6,000 per month for every six seconds it shaves from a service's historical EWT. On the other hand, it could lose up to $4,000 for every six seconds it exceeds the EWT by.
The idea comes from London's system.
There, every 0.1-minute (six-second) improvement in EWT earns a bus operator a bonus amounting to 1.5 per cent of its annual operating contract value. For every 0.1-minute of deterioration, 1 per cent will be deducted from the contract.
The scheme has clearly worked since it started in 2001. Buses in London arrive every two minutes during peak hours along some routes, rivalling the frequency of trains. And even if they are held up, they are often no more than a minute late.
The London scheme does have drawbacks, though. For instance, buses can be taken out of service halfway through their journeys if bunching occurs. This means passengers will be asked to get off and take the next bus, or make alternative travel plans.
Speaking to reporters at the launch of City Direct service 652 yesterday, Transport Minister Lui Tuck Yew said the new reliability framework will need to be "fine-tuned along the way".
He said: "It is the start of a programme that, if done properly, can make quite a difference."
City Direct service 652 travels between Upper Thomson and the city centre during peak hours.
Operated by Ren Quan Transport, which has a fleet of about 30 buses, it is the second of 10 supplementary services to be contracted out to private operators. The first was from Jurong West to the city and back.
