The number of off-peak car (OPC) offences soared to a new high last year even as the population of red-plate cars continues to dwindle.
According to the Land Transport Authority (LTA), there were about 23,160 offences last year, nearly twice the number in 2011 and about 19 times more than in 2009.
An LTA spokesman attributed the spike to a more effective enforcement regime under the e-Day licence system, introduced in November 2009.
Previously, OPC owners had to buy a paper permit and display it on the car's windscreen before driving.
Now, OPC drivers can buy the e-Day licence after using their car outside of the 7pm-7am period on weekdays, as long as they do so before midnight the next day.
The LTA spokesman said with the e-Day licence, enforcement officers can take down an OPC's registration number and check it, instead of stopping cars on the road to check for paper licences. Traffic surveillance cameras also capture the number plates of OPCs, which are checked against purchase records.
All the offences involved cars that were on the road without valid e-Day licences.
Under the law, first-time offenders can be fined up to $5,000. Repeat offenders are charged in court and face a fine of up to $10,000.
The increase in offences comes even as the total off-peak car population continues to slide. The number of red-plate cars has gone down from 47,899 at the end of 2011 to 43,584 in June.
Part of the slide is due to far fewer new off-peak cars being registered every month. The number of new registrations has seen a steady decline, from 781 in 2011 to 469 last year.
In the first six months of this year, just 81 new off-peak cars were registered, a 73 per cent decrease compared to the same period last year.
Under the OPC scheme, drivers get a rebate of up to $17,000 to offset the certificate of entitlement (COE) and Additional Registration Fee.
National University of Singapore transport researcher Lee Der Horng said that incentive has become "fairly small" after COE prices crossed the $50,000 mark in 2011 and continued to head north.
"At current prices, those who want to get an OPC will walk away."
In 2011 and last year, more than 3,000 motorists opted to convert their OPCs to the normal scheme.
Senior project executive Suresh Naidu, 31, did that for his Ford Focus in March when he moved to Johor and had to commute across the Causeway daily. "Thinking long term, it was not worth it to pay $20 every day."