Briefly describe the traffic characteristics associated with each of the levels of service for basic freeway sections.

Question

What will be an ideal response?

Answer 1

At LOS A free flow conditions prevail. Vehicles are not impeded by other
vehicles. Effects of minor incidents or breakdowns are easily absorbed.
At LOS B, reasonably free flow conditions still exist and vehicles continue to
travel at free flow speeds. Ability to maneuver within the traffic stream is slightly
restricted. Effects of minor incidents or breakdowns are easily absorbed.
At LOS C, speeds are at or near the free flow speed, but freedom to maneuver is
noticeably restricted. Lane changes are more difficult. Minor incidents result in
significant deterioration in local level of service.
At LOS D, speeds begin to decline slightly with increasing flows. Freedom to
maneuver is noticeably limited and drivers experience reduced physical and
psychological comfort. Minor incidents will result in queuing as little space is left
in the traffic stream to absorb disruptions.
At LOS E, operations are volatile because there are virtually no gaps; volume is at
or near capacity. Maneuvers such as lane changing or merging traffic at entrance
ramps will result in a disturbance of the traffic flow. Any incident can be expected
to cause extensive queues as the traffic stream has no ability to dissipate its
effects.
At LOS F, breakdown conditions exist and uniform moving flow cannot be
maintained. The flow conditions are such that the number of vehicles that can
pass a point is less than the number of vehicles arriving at that point.