Measures of effectiveness for level-of-service assessment of two-lane roads: An alternative proposal using a threshold speed

Abstract

This paper presents an alternative way of using average travel speed and percentage of traffic in platoons [the two measures of effectiveness currently in Highway Capacity Manual (HCM) methodology] to evaluate level of service. The definition of a threshold speed that is acceptable to users is implied. Travelers expect different things of different roads, and in the case of two-lane highways the desire to pass and the stress or mild frustration of being delayed are not a function only of headway or of the difference between actual and desired travel speed. Therefore, simplistic approaches do not accurately reflect the point of view of the roadway user. The procedure can be adapted to various two-lane highway types. It could be used for Types I and II already in HCM procedure and for other types that may be considered in the future.