Research Activities: 2000

Automated Mobile Highway Sign Retro-Reflectivity Measurement




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Sequential Number


Identification Number


Matching Research Agency

Rock Mechanics

Principal Investigator

Norbert H. Maerz, Assistant Professor
Rock Mechanics
University of Missouri-Rolla
214-A Rock Mechanics
Rolla, MO 65409-0660
p(573) 341-6714
f(573) 341-4368

Student Involvement

One (1) M.S. student

Project Objective

Develop a mobile image based capability to measure road signs

Project Abstract

This proposal asks for funding to prove the concept of using digital video image analysis to measure highway sign retrofit-reflectivity and to use the same analysis for classification of the signs. The system will use real time image analysis of night images of roadway signs acquired on a mobile platform moving at highway speeds, illuminated by normal vehicle head lamps. This arrangement is the closest possible scenario to the actual design use of retro-reflective signs, which is to provide visual warnings for drivers driving at highway speeds at night, where the signs are being illuminated by vehicle headlamps. This approach is better than current technologies. These consist of hand-held measurement devices that are not capable of analyzing large numbers of signs, nor of measuring average values over physical extend of a sign. This approach will also have significant advantages over an FHWA mobile measurement device under development, which requires a laser range finder, a second operator, and electronic strobes, and results in significantly higher acquisition and maintenance costs.

Task Description

Imaging capability to measure road sign retro-reflectivity.

Anticipated Benefits

Allow the implementation of minimum retro-reflectivity standards.

Modal Orientation



Project Start Date:01/01/2001
Project End Date:12/31/2001

Relationship to other Research/Projects


Technology Transfer Activities

Results presented at the TRB Annual meeting 2002.

Transportation Research Board Keywords

Retro-reflectivity and highway signal tester