The Changeable-message concept of traffic control
Subtitle: report of a conference held July 15-16, 1971.
Series: HRB special report 129; Special report (National Research Council (U.S.). Highway Research Board) ;; 129.
Publisher: Highway Research Board, National Research Council
Published: 1972
Place of publication: [Washington]
Language: eng
Number of pages: 48
Subjects: Traffic signs and signals.; Electronic traffic controls.
Notes: Includes bibliographical references.