Page 89 - Lecture Notes DCC3113

Permanent Road Studs divide into two types:

i. Snow-ploughable Raised Road Studs
These road studs have prisms set in metal castings and installed
in a cut made by a drop saw using 51 cm radius blades
surrounding a number of 46 cm radius blades. The castings are
installed using a 2-part epoxy and are designed to protect prisms
from vehicular traffic and snowplough damage.

ii. Recessed Reflective Road Studs
These road studs are installed in grooves cut in the road by a
specially designed cutting head. The grooves are approximately
1.2 m long for one-way markers and 2.1 m long for two-way
markers. The stud is installed with a 2-part epoxy and sits in the Figure 6-6: Road studs
low point of the groove approximately 1.6 cm below the road
surface.

Temporary Road Studs

These road studs are traditionally used in work zones, spaced from 1.5 m to 24 m apart and installed
with a 2-part epoxy or bitumen. When the work zone needs to be altered, the temporary studs are
removed with little or no damage to the existing surface.

b. Posts delineator

Posts Delineator are effective aids for nighttime driving.
They are considered to be guide, markings rather than warning
devices and should never be substituted for a proper warning sign.
The purpose of delineators is to outline the edge of the roadway
and to indicate the roadway alignment. Post delineators usually
consist of reflector units (glass, plastic, or reflective sheets)
mounted on suitable supports.

Post mounted delineators are beneficial for horizontal
curves over 5°. It should be pointed out that whilst installation of
such delineators or markers will assist night driving, it may also
encourage drivers to increase speed. Unless other safety features
are correspondingly increased, such installation can give drivers a
false sense of security. Measures should be taken to improve the
superelevation of the road at the bend.
Figure 6-7: Post Delineators
Post delineators are simply reflector units mounted on
suitable supports. Both the reflector units and the supports should be of types approved by J.K.R. The
reflector units may be of the circular corner-cube prismatic lens type and shall be not less than 75 mm
diameter. They can also be made of glass, plastic, or reflective sheetings. Reflective sheetings should be
of rectangular shape 180mm x 50mm and should be of the high intensity retro-reflective material.

These reflector units must be capable of clearly reflecting light under normal atmospheric
conditions from a distance of 300 meters when illuminated by the upper beam of standard automobile
lights. Timber posts should be of hardwood timber painted with stripes of black and orange.

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