Citation

Lunenfeld H, Alexander GJ. Transp. Res. Rec. 1976; 600: 1-6.

Copyright

(Copyright © 1976, Transportation Research Board, National Research Council, National Academy of Sciences USA, Publisher SAGE Publishing)

DOI

unavailable

PMID

unavailable

Abstract

Drivers often experience difficulty when freeway lanes are not continued beyond an interchange. Interchange land-drops represent situations that drivers do not expect and for which they are unprepared. The problem was studied to aid the driver's task by developing effective signing treatments. Devices in the Manual on Uniform Traffic Control Devices (MUTCD) were found to be not entirely satisfactory because of questions about their applicability, latitutde in their application, and suitability for their intended purpose. Data from surveys, a state-of-the- art review, observations of as-built installations, and laboratory evaluations were used within the framework of a human factors analysis to assess MUTCD standards and recommend changes. Driver expectancy provided the basis for problem identification and solution development. Configurations were categorized by geometric and route attributes into eight types of exists and splits. Their concomitant expectancy violations were identified, and their effect on unfamiliar drivers was assessed. Each type violated the expectancy that all lanes will continue. Additional differing geometric and route expectancy violations precluded the use of a single signing treatment for all types. The black-on-yellow EXIT ONLY treatment was recommended for exit lane drops with route continuity. Diagrammatic treatments were recommended when the off-route was to the left of the through-route. Empirical evaluations demonstrated the effectiveness of the recommendations.