Motorists using the Whanganui River Rd should have noticed an 80km/h speed restriction now in place.
It used to carry the open road 100km/h limit but Whanganui District Council and its iwi liaison committee believe that was too fast for this type of road.
The change has been driven by a number of things, including growing tourist traffic volumes as well as more cyclists completing the Mountains to the Sea cycleway.
The River Rd is generally narrow for much it its length as it winds its way along the banks of the Whanganui River from State Highway 4 north of the city to Pipiriki.
Reducing the speed limit was first raised late last year but at that stage council was talking about a district-wide 80km/h limit on all rural roads. That suggestion has now been deferred at the request of the New Zealand Transport Agency.
The agency is carrying out trials on an 80km/h limit on roads in the Waikato and it has asked Whanganui and other councils pondering similar decreases to wait until trials are over.
Council senior roading engineer Rui Leitao said the new speed guidelines that would come from the trial are expected to align with what Whanganui council wanted to do.
However, there was nothing to stop the council pushing for an 80km/h speed limit on the River Rd. Mr Leitao said with the exception of some key rural routes, the general safe driving speed for all the other rural roads was no more than 80km/h.
More consultation would follow with the rural community board and police, and council would then need to approve a draft of the bylaw before it went out for public consultation. The council was bound to review its bylaw as a legal requirement and because circumstances on road use were changing. The existing bylaw is valid until 2018.