What are the three measures used to describe service quality for a two-lane highway? Which of the measures are used to describe level-of-service for Class I Class II, and Class III highways?

Question

What will be an ideal response?

Answer 1

There are three measures used to describe the service quality of a two-lane
highway. These are (1) percent time following another vehicle (PTSF) (2) average
travel speed (ATS) (3) and percent of free-flow speed (PFFS).
LOS for Class I highways is based on two measures: PTSF and ATS. Because
speed and delay due to passing restrictions are important factors to these
motorists.
LOS for Class II highways is based on a single measure: PTSF. As travel speed is
not a key factor but delay measures the motorist’s sense of the quality of the trip.
LOS for Class III highways is based on a single measure: PFFS. In this situation
where the length of the Class III segment is limited, neither high speeds nor
passing restrictions are of major concerns. Motorists in a Class III situation are
most concerned with the ability to maintain steady progress through these sections
at or near the speed limit.