A recent spike in thefts of vehicles with security-weak lockboxes is prompting the Honolulu Police Department to advise drivers to carry their keys with them rather than relying on the device for safekeeping.

Since April there have been 150 thefts of vehicles in which lockboxes were being used to store keys. That includes 19 thefts so far this month. In October there were 27 thefts.

“That’s almost a car a day,” said Sgt. Kim Buffett, coordinator of CrimeStoppers, during a news briefing Tuesday.

Lockboxes resemble large padlocks and are typically opened with a combination lock setting rather than a key. Motorists attach a lockbox to a vehicle’s frame, trailer hitch or tow hook to store their car key. In all of the theft cases, Buffett said the lockboxes were attached to the back of the vehicle.

Buffett said criminals use bolt cutters to detach the lock, then take the device elsewhere to smash it open. As it can take just a few seconds to cut a lockbox, thieves oftentimes return to the scene within a few minutes of swiping the device to steal the vehicle.

Buffett advises the public to be aware of their surroundings.

The Police Department began tracking the number of thefts of vehicles with lockboxes in April after officers saw an influx of cases. The lockbox break-ins are occurring everywhere on Oahu, from shopping malls to beaches, Buffett said.

In addition, Buffett advises shoppers to not leave valuables in cars, especially during the holidays, when break-ins are expected to increase by 10 percent. Police see a lot of “smash-and-grabs,” in which thieves shatter a car window and steal items inside, she said.

“Please do not leave your valuables in the car anywhere you park. And if you have to, make sure you hide them before you get to the destination,” she said.