While two of the three mechanised carparks in Housing Board estates - Changi Village and Yishun - can have utilisation rates of more than 90 per cent during peak hours, it is not the case for the one in Bangkit Road, which sees just around half its spots taken up in its busiest periods.
The mechanised parking systems (MPS) started operation last December and January, with those in Bangkit Road and Yishun for season parking and the Changi Village one open to short-term users too.
The HDB says it plans to allow short-term parking at the mechanised carpark in Bangkit Road in Bukit Panjang later this year where "the needs of our season-parking ticket holders are adequately met".
There are 26 parking spots in the Yishun mechanised carpark, 60 at the one in Bangkit Road, and 195 in Changi Village, where the mechanised carpark is near offices and eateries and is most popular during lunch and dinner on weekdays.
In Yishun, residents said the mechanised carpark is well used, with vacancies falling to single digits at night. But at Bangkit Road, vacant spots remained at around 50 between 8pm and 9pm when The Straits Times visited last Thursday.
At a mechanised carpark, users drive into a lift before exiting their vehicle and entering a PIN code outside. The car lift doors then close and the system automatically parks the vehicle. It is retrieved by entering the same PIN code.
Those who use the mechanised carparks told The Straits Times the system is convenient and safe, despite the occasional glitch. For those who do not use them, waiting time is a major concern.
"We cannot afford to wait five, 10 minutes in the morning. My kids will be late for school," said Mr Low Soon Peng, 45, a safety officer living in Yishun. He uses the mechanised carpark only on weekends.
It takes 10 to 15 minutes for users to retrieve their cars during the peak period and an average of five minutes during the off-peak period, said the National Development Ministry.
Motorists who need to use the car frequently also find it a hassle to park at a mechanised carpark.
Said retail manager Jo Yang, in her 40s, who works in Bangkit Road: "It's not very convenient for shopkeepers like us. We have to move merchandise sometimes and it's troublesome to go in and out of the carpark."
Other problems related to the three mechanised carparks include breakdowns. In half a year, there were 11 breakdowns out of some 54,000 parking transactions, mainly due to user issues such as motorists forgetting to apply their parking brakes, said MND last month.
Fans of the system, however, cited advantages such as security.
Yishun resident K. Krishna, 61, director of a human resource consultancy, said: "When I go overseas, I can leave my car there for a month. In the open-air carpark, you don't know what's going to happen but (at the mechanised carpark), I'm very sure the car is safe."
SIM University senior lecturer in urban transport management Park Byung Joon said such systems make it "quite easy to increase the parking capacity by (at least) threefold".
He said: "It has been implemented in cities like Seoul and Tokyo for many years. Given the scarcity of land in Singapore, MPS is really a way forward."
But Dr Park added that engineers will need to shorten the time for retrieving cars, as a 15-minute wait during peak hours may almost be "psychologically unacceptable" for users.