Singapore's private car population has fallen to its lowest level since 2011, and the shrinkage could continue.
The latest available figures from the Land Transport Authority show that there were 598,219 cars as of the end of last month - down from 600,176 last year. The number stood at 607,292 in 2013, and 605,149 in 2012.
The car population is now at its lowest since 2011, when there were 592,361 cars on the road.
The shrinkage is a rare occurrence in Singapore, where a quota system allows the vehicle population to grow annually at a pre-determined rate.
Observers said the contraction is a sign that the supply of certificates of entitlement (COEs) is lagging behind actual replacement demand.
Since 2010, COE supply has been formulated largely by the number of cars scrapped in the preceding months. This often does not correspond with the number of cars scrapped in the following months. For instance, last year's May-July COE quota for cars was determined by the 7,083 cars scrapped from February to April. But actual scrappage from May to July was higher at 7,514.
Over time, this leads to a population shrinkage.
NUS Business School Associate Professor Chu Sing Fat said the shrinking Open category, which can be used for any vehicle type but ends up mainly for cars, also contributes to the phenomenon.
Mr Lee Hoe Lone, managing director at Audi agent Premium Automobiles, said: "It will be worse if they start holding back some COEs."
He was referring to a widely expected move by the Government to "save" some COEs arising from the 2015-17 supply bonanza for the next low-supply period starting from 2019.
"The writing is on the wall," said Dr Park Byung Joon, an urban transport management expert at UniSIM. "I do not see any other way to avoid having a few years of massive COE supply followed by a dry spell."
National University of Singapore transport researcher Lee Der Horng concurs, adding that "a more equalised COE supply between years is more healthy".
While motor traders agree that a peak-and-trough COE supply pattern is not desirable, they reckon an adjustment - by holding back some certificates - will not be well received by consumers who have been waiting for supply to surge.
"If they hold back 30 per cent of next year's supply, it could potentially mean 30,000 car-owning families giving up their cars," a trader said.
Jardine Cycle & Carriage managing director of motor operations Eric Chan suggested that Singapore could accommodate a higher vehicle population once the second generation of Electronic Road Pricing (ERP II) is up.
On top of time and location, ERP II can charge according to distance clocked. With the system, expected to be ready before 2020, Mr Chan said "we can have higher car registrations but fewer cars on the road".
But even if COE supplies are not tweaked, the car population is likely to shrink for a few more years if the current COE quota formula is not changed.
Observers pointed out that the Government aims to raise public transport's share of morning peak journeys to 70 per cent by 2020 - up from 63 per cent in 2013.