The number of people prosecuted for keeping deregistered vehicles - which are supposed to be scrapped or exported - has soared.
According to the Land Transport Authority (LTA), 432 were charged in court in the first seven months of this year. That works out to an average of 62 per month - the highest in at least five years.
The average monthly figure from 2010 to 2014 ranged between 44 and 57. The actual figure could be much higher, as it is hard to detect deregistered vehicles in a population of almost one million vehicles.
A spokesman for the LTA said it relies on its enforcement officers who do random checks in their daily patrols. He said the authority also "follows up on feedback received from members of the public on deregistered vehicles".
Motor industry sources said the spike in cases could be fuelled by a shortage of export-processing zones (EPZs), where deregistered vehicles are kept under lock and key before they are exported.
people charged in court in the first seven months of this year for keeping deregistered vehicles
people charged on average each month - the highest in at least five years
From a peak of 12, the number of EPZs has dwindled to two following a dry spell for deregistrations between 2009 and 2013.
But deregistrations started to pick up sharply last year and are expected to continue rising for the next three years.
Not all offences are because of a dearth in authorised storage space.
Motor trader Anthony Lim said he is facing charges for not keeping a deregistered Ferrari he was exporting in an EPZ. "My dealer said for such a high-end car, he did not want to take the risk of it being damaged in a crowded EPZ," he said.
Car exporter C. S. Ng said falling overseas demand for old used cars may be a contributing factor. "Last time, you may get $5,000 for a car if you export it but, today, you won't get more than a few hundred dollars for the same car," he said.
Because of this, some motor traders take the risk of not putting their deregistered cars in an EPZ, which charges around $200 per month per car.
Another motor industry player said some offenders are simply out to cheat.
"They would drive across the Causeway, get their export documents stamped by Customs, and then return to Singapore later," said the veteran trader, who did not wish to be named.
With the stamped export documents, these rogue traders will claim the scrap rebate from the LTA, and continue to make use of the deregistered vehicle, sometimes with a fake number plate.
"Some even rent out these cars to unsuspecting third parties," the trader said.
The LTA said any person who uses or keeps an unregistered vehicle can be fined up to $2,000 or jailed for up to three months. Repeat offenders can be fined up to $5,000, or jailed for up to six months.
Those convicted have been slapped with stiffer penalties when several vehicles are involved.
In 2006, the manager of three motor trading firms was sentenced to 28 weeks' jail for such an offence involving 30 vehicles.
The prosecutor had urged the judge to impose a deterrent sentence because the number of offences had soared, and because detecting such cases was "very difficult''.
Given the high cost of cars here, the rewards still seem to be worth the risk of getting caught - going by the noticeably higher number of prosecutions so far this year.