The spiked "cat claw" device which failed to snare a Mercedes- Benz when it sprang from the road at Woodlands Checkpoint is best used in combination with secondary vehicle immobilisers - but not as a stand-alone last line of defence.
Security equipment vendors told The Straits Times that cat claws flip up between one and three seconds of activation and mainly cause damage to tyres, but may not be enough to stop a vehicle from driving off.
They suggested the additional use of road blockers, or "rising kerbs". These are short metal walls or steep ramps of up to a metre high that shoot up from the ground as quickly as three seconds after being triggered.
The Straits Times understands that Woodlands Checkpoint has several lane-wide metal cat claws, but does not use these in conjunction with road blockers.
The Immigration and Checkpoints Authority (ICA) said its cat claws rise to about 30cm in height and are "able to withstand vehicles weighing 6 tonnes travelling at 80kmh".
"Cat claws are best used in combination with road blockers," said Mr Jimmy Leow, managing director of TJ Systems which specialises in high-end security equipment and systems here. "The spikes are only for tyres, and road blockers are more effective in stopping the whole car."
He suggested having road blockers installed 3m to 4m after the cat claws at the border.
Mr David Tan, director and general manager of security solutions firm Securitex, said the pairing of these two barrier types has proven "very effective" in other countries.
"If you want to completely stop vehicles, especially at checkpoints, we would recommend the cat claws be used together with another barrier, such as road blockers," said Mr Tan, who has been selling homeland security hardware since 1997. "I'm not sure why we only have cat claws functioning alone at the border. Perhaps it is because there have hardly been any major incidents so far in Singapore."
Such heavy-duty vehicle barriers are typically found in high security areas here - like army camps, embassies and Changi Airport - as well as at private properties such as those in Marina Bay Sands and Resorts World Sentosa.
Mr Tan said he thought demand would spike after the September 11 terrorist attacks in the US, but the market for these barriers remains small, limited mostly to government compounds.
Cat claws are mainly sourced from Britain and the US and can cost around $40,000 per unit before installation expenses. Road blockers are more common here and their popularity has been rising as their parts can be produced here, allowing purchasers to do away with high freight costs.
ICA said preliminary investigations by the vendor of the Woodlands Checkpoint cat claws revealed the affected barrier "did not work optimally" when the Mercedes-Benz hit it.
The vendor is helping ICA with its investigations and the affected lane has been closed since the incident as the cat claws are being repaired. ICA said that a mobile crash barrier has also been put in place, and the authority will review further enhancements.
Get a copy of The Straits Times or go to straitstimes.com for more stories.