Section 3: Retroreflectorization
Introduction
"Retroreflectorization" refers to the property of the sign
sheeting material that causes light to reflect such that the paths
of the rays are parallel to those of the incident rays.
Sign retroreflectorization is accomplished by the use of a
commercially made retroreflective sheeting applied to the substrate.
Retroreflective Sheeting Types
There are several types of retroreflective sheeting. They
are primarily classified by their brightness. Various factors determine
the desirability of one type of sheeting over another on certain
types of signs. Texas Department of Transportation (TxDOT) standards
call for the following types:
- Type A (High Intensity)
- Type B or C (Prismatic)
- Type D (Prismatic)
- Acrylic Non-Reflective Film
Fluorescent Retroreflective Sheeting Types
Fluorescent sheeting is also available on all sheeting types
mentioned above. They are called out by using abbreviation FL as
subscript in the type of sheeting used.
TxDOT Standard
TxDOT's standards for retroreflective sheeting on various
types of signs are detailed on the
(TSR Series).
All construction plans should reflect the retroreflective
sheeting standard. Existing signs not in conformance with the standard
should be replaced on a maintenance replacement basis.
Deterioration of Retroreflectivity
The retroreflective quality of the sheeting material deteriorates
over time, eventually requiring replacement of the sign. Premature
failures of the sheeting should be reported to the Traffic Materials
Branch of the Construction Division. A
Guide for the
Collection of Warranties on Sign Face Materials
has
been developed to assist districts who encounter premature failures.
(See Chapter 4 for information on maintaining proper retroreflectivity.)