Traffic LOS (Level Of Service)

Follow Marin Events

• HomeUpMTC SPENDING: Transit v HighwayBRT & Roadway ExpansionWhat can we learn from LA NewurbanismTraffic LOS (Level Of Service)Blueprint Briefing Book •
•  •

Development Denied when Traffic is Congested
Half Moon Bay (and San Rafael, apparently) allows new development ONLY if road and other services are adequate.
Lack of adequate road and services shall be grounds for the denial of a development permit.
page 24

Level of Service (Traffic):  (L.O.S.)
A scale that measures the amount of auto traffic that a roadway or intersection accommodates, based on such factors as maneuverability, driver dissatisfaction, and delay. for intersections. Determines the impact of auto traffic resulting from new development. Levels of service are:
The Volume to Capacity Ratio (V/C) is also usually shown for each signalized intersection.  V/C measures the relationship of the volume of traffic in an intersection to the capacity of the intersection.
How long cars wait at signalized intersections
A     0-10 seconds     D   >35-55 seconds
B >10-20 seconds    E    >55-80 seconds
C >20-35 seconds     F   >80 seconds

V/C ratio >.59

0-10 seconds
Indicates a relatively free flow of traffic, with little or no limitation on vehicle movement or speed.
bullet Free flow conditions
bullet Low volumes
bullet High operating speed
bullet Uninterrupted flow
bullet No restriction on maneuverability
bullet Little or no delay
bullet Drivers maintain desired speeds


V/C ratio .60 - .69

10-20 seconds
Describes a steady flow of traffic, with only slight delays in vehicle movement and speed. All queues clear in a single signal cycle.
bullet Stable flow conditions
bullet Operating speeds beginning to be restricted


V/C ratio .70 - .79

20-35 seconds
Denotes a reasonably steady, high-volume flow of traffic, with some limitation on movement and speed, and occasional backups on critical approaches.
bullet Stable flow but speed and maneuverability restricted by higher traffic volumes
bullet Satisfactory operating speed for urban conditions
bullet Delays at signals


V/C ratio .80 - .89

35-55 seconds
Designates the level where traffic nears an unstable flow. Intersections still function, but short queues develop and cars may have to wait through one cycle during short peaks.
bullet Approaching unstable flow
bullet Low speeds
bullet Major delays at signals
bullet Little freedom to maneuver


V/C ratio .90 - .99

55-80 seconds
Represents traffic characterized by slow
movement and frequent (although momentary) stoppages. This type of congestion is considered severe, but is not uncommon at peak traffic hours, with frequent stopping, long-standing queues, and blocked intersections.
bullet Lower operating speeds
bullet Volume at or near capacity
bullet Unstable flow
bullet Major delays and stoppages


V/C ratio 1.00+

>80 seconds
Describes unsatisfactory stop-and-go traffic (Marin freeway  today)
characterized by “traffic jams” and stoppages of long duration. Vehicles at signalized intersections usually have to wait through one or more signal changes, and “upstream” intersections may be blocked by the long queues.
bullet Forced flow conditions
bullet Low speeds
bullet Volumes below capacity may be zero
bullet Stoppages for long periods because of downstream congestion


L.O.S. for autos presently does not consider the impact on pedestrians or bicyclists.
See San Rafael's Congestion Standards

Sausalito Policy
Solutions to transportation problems facing Sausalito cannot be achieved without cooperation and joint planning with all Marin jurisdictions. Recognizing this the City is committed to working jointly on regional transportation planning efforts. These include the Highway 101 Corridor Study Committee and the County Planning Agency acting as the Congestion Management Authority.
Countywide efforts include the development of a Transportation Systems Management (TSM) Program and the establishment of a Regional Traffic Mitigation Fee. The City will work with other Marin cities and the County of Marin in the development of these and other regional transportation efforts. It is the City's position that transportation improvements should address existing deficiencies and accommodate managed growth in the County.