New barriers are being installed in police cars to protect frontline officers from violent and unruly backseat passengers.
The idea of protective barriers was mooted about 10 years ago. After trials and tweaking, the barriers will be installed between the front and back seats of some police cars in the coming months.
The move was revealed in the Police Association monthly magazine Police News.
It comes after numerous reports over the years of incidents including officers being punched, kicked and spat at by offenders placed in the back seat.
Trials using full perspex barriers were undertaken in Taranaki and Whanganui in 2017.
But a "variety of issues" were highlighted.
Police national fleet manager Rob Morgan, who has overseen the project from the start, said full barriers restricted movement of the front seats, which meant difficulties for bigger and taller officers.
He said the perspex also caused visibility and glare issues as the headlights of oncoming vehicles reflected off the barrier and interfered with the rearview mirror.
A full barrier also meant it was difficult to communicate between the front and back seats.
As a result, Morgan said a modified polycarbonate barrier was designed to fit only between the seats - identified as the main area of risk for police officers - but prevent anyone slipping an arm or hand through the gap.
With the barrier in place, the front seats were still fully adjustable and Morgan said the design allowed "good communication between the front and back of the vehicle".
The barriers have also been set at an angle to "diminish any reflected glare".
Morgan said he was "very proud" the organisation had come to "a solution that meets the needs of frontline police".
According to Police News, from last month the barriers were ready to be installed into new ZB Commodore and the old VF Commodore vehicles in the police fleet.
The Colorado customised barriers were said to be next off the production line.
The design of the barriers, manufactured by Auckland company Best Bars, was overseen by the police fleet group.
Morgan said each district would be left to identify which of its vehicles had the barriers installed - rather than a "nationwide rollout".
Each barrier costs about $500 to buy and about $150 to install.
"Throughout the process we encountered a range of opinions from staff, from it being urgent to those who didn't want the barriers because it would make it difficult to reach their lunch in the back seat," Morgan said.
The new safety device is supported by the Police Association which sees it as an "opportunity to improve the health and safety of members".