Level of Service (LOS)

“Level of Service” (LOS) is a qualitative description of operating conditions of the transportation system, measuring the effect of a number of factors, including travel flow, vehicle delay, travel speed, traffic interruption, freedom to maneuver, safety, driver comfort and convenience. Levels of service are designated “A” through “F” from best to worst, covering the entire range of traffic operating conditions. LOS “A” through “E” generally represent conditions where traffic volumes are at less than the facilities capacity, while LOS “F” represents conditions where capacity is exceeded and/or forced conditions exist.

The City of Roseville has a policy to maintain LOS “C” or better at a minimum of 70% of all signalized intersection and roadway segments within the p.m. peak hour. The p.m. peak hour is defined by the highest hour for overall traffic volumes during the day.

Click here for existing and future 2025 LOS at signalized intersections

The following table provides a description of level of service categories for signalized intersections:

Level of Service Definitions at Signalized Intersections

Level of Service (LOS) Volume-to-Capacity Ratio Description
A 0.00 - 0.60 Free-Flow/Insignificant Delays: No approach phase is fully utilized by traffic and no vehicle waits longer than one red signal indication.
B 0.61 - 0.70 Stable Operation/Minimal Delays: An occasional approach phase is fully utilized. Many drivers begin to feel somewhat restricted within platoons of vehicles.
C 0.71 - 0.81 Stable Operation/Acceptable Delays: Major approach phase fully utilized. Most drivers feel somewhat restricted.
D 0.82 - 0.90 Approaching Unstable/Tolerable Delays: Drivers may have to wait through more than one red signal indication. Queues may develop but dissipate rapidly, without excessive delay.
E 0.91 - 1.00 Unstable Operation/Significant Delays: Volumes at or near capacity. Vehicles may wait through several signal cycles. Long queues form upstream from intersection.
F Greater than 1.00 Forced Flow/Excessive Delays: Represents jammed conditions. Intersection operates below capacity with low volumes. Queues may block upstream intersections.
The ratio is the traffic volume demand at an intersection to the capacity of the intersection.
The City of Roseville has established a volume-to-capacity ratio of 0.81 at the LOS "C" threshold.

Scott Gandler, P.E.
Senior Civil Engineer in Charge

Development Services - Engineering
Transportation Planning
311 Vernon Street
(916) 774-5339
(916) 746-1339 Fax
(916) 774-5220 TDD