Marking The Edge Of The Road With Reflective Road Studs

To help drivers see the direction of the road during the day and night,road studs (also known as cat eyes or pavement markers) are usually installed on the left and right sides of the road.

Why do we use reflective road stud on the road?
Road studs are also known as cat eyes or reflective raised pavement markers (RRPM). There are several types of reflective road studs and they have three functions.

Visual lane markings – white in the middle and red on the left edge indicate that road users can follow these markings to stay in the lane. Use yellow where there is no yellow overtaking line to add visual effects to the rules.

Tactile lane marking – if you’re driving on a road stud, you can sense it through the vehicle’s suspension and steering, so it’s a tactile reminder that you’re veering off the road.

Special function marking – hydrants are marked with blue raised reflective road studs and in some areas culverts and drains are marked with green reflective road studs.

Reflective road studs on road have several different colors.

* Blue marks the location of a fire hydrant. Blue reflectors are installed on, or just to the left of the centreline of the roadway. They were first introduced in 2004. They are called retroreflective raised pavement markers or RRPMs. In other countries they are called road studs. While you might not notice them while you are driving around, they are useful for vehicles attending a fire because they can quickly locate a source of water.
* Green marks the location of a culvert
* Yellow marks the centre line when you are not allowed to pass, as in the image below, or the right edge of a motorway
* White marks between lanes, and where you are permitted to pass
* Red marks the left edge of a motorway

On unilluminated country roads, reflective road studs are arranged in groups of four, one meter apart and 10 meters between each group. Only one of the four road studs is reflective.

In the case of no overtaking lines, the reflective road stud are separated by 20m from each other.

When overtaking is allowed, red reflective road studs are marked on the left edge of the lane and white reflective road studs are marked on the centerline.