R1-5.2.1 or RS52.1 Threshold Signs are used on approaches to towns, to make drivers more aware of a speed restriction and the start of a lower speed environment. R1-5.2.1 Rural Threshold Signs are a new smaller rural version of the original rural 1900 x 2700 signs.
The newer version has the halo around the outside of the speed circle, which enhances the design.
Highest speed limits is the number of km/h shown on the sign; combined with name of locality reached.