Officials are stepping up attempts to impose a 20mph speed limit on central Belfast - despite evidence it is not being enforced.
They have ordered more signs, which will be added around the city centre imminently.
It comes despite the PSNI not catching a single speeding motorist in the six months since the speed limit was cut.
A review of the controversial 20mph scheme is due to take place next year.
But Infrastructure Minister Chris Hazzard said it had not led to any traffic problems in the city centre.
"The introduction of a 20mph speed limit in the core of Belfast city centre in January 2016 was to reduce the number and severity of collisions," he explained.
"Introduction of the speed limit followed agreement with the PSNI, who are responsible for the enforcement of speed limits.
"There were also discussions with other key stakeholders, including Belfast City Council.
"The department will be carrying out a review of the effectiveness of the 20mph speed limit in 2017, after it has been in place for a year. Transport NI has been reviewing the existing signs with the PSNI, and a number of additional signs have been ordered and will be erected within the next four weeks."
Proposals for a 20mph city centre speed limit were first published in July 2014.
The restriction came into operation on January 31 this year.
Motorists must reduce their speed on 76 city centre streets, including Donegall Square, Dunbar Link and in the Cathedral Quarter area and more.
But more than six months since it started, not a single driver has been caught speeding in this area. Nor has any attempt been made to catch drivers breaking the new 20mph limit.
The PSNI said: "On the PSNI systems, there have been 0 (zero) detections for speeding within 20mph limits. The searches included were for any fixed penalty notices issued, discretionary disposals issued or drivers referred for prosecution."
The PSNI was also asked how many times officers had used speed cameras to catch motorists breaking the 20mph limit.
It responded: "The PSNI do not operate/manage the speed cameras in Northern Ireland.
"They are operated and managed by the NI Road Safety Partnership, and there are currently no permanent or community concern sites enforced within the 20mph limits in Belfast.
"In addition, Belfast resources have not deployed any speed cameras in the area".
Belfast councillor Jim Rodgers called for the 20mph speed limit to be scrapped, claiming it is deterring shoppers. He said: "It has been a waste of time and money."
But Chief Inspector Diane Pennington, from the PSNI's road policing unit, defended the lack of police action.
"Police will continue to monitor traffic and enforce where appropriate following the introduction of the new 20mph speed limits in Belfast city centre," she said.