Tudor Wharf Draft Environmental Impact Report EOEA # 6744 



8.5 Level of Service Description 



Level of service (LiOS) is a quantitative 

 measure used to describe the operation of 

 an intersection. Values range from A to 

 F, A representing very good operation and 

 F representing very poor operation. 

 Level of service calculations are 

 performed using methods in the 1985 

 Highway Capacity Manual (HCM) , published 

 by the Transportation Research Board. 

 For signalized intersections, level of 

 service is defined in terms of average 

 stopped delay which is determined using 

 an analysis method relating traffic 

 volumes, geometric conditions, and 

 traffic control conditions. Delay is a 

 measure of driver discomfort, 

 frustration, fuel consumption, and lost 

 travel time. The ratio of existing 

 traffic volume to available capacity 

 (volume/capacity ratio) provides a 

 measure for the intensity of traffic 

 loading relative to the ability of the 

 street to handle the traffic. The number 

 of lanes, presence of turn lanes, type of 

 traffic control, and signal phasing are 

 important capacity determinants. As the 

 volume/capacity ratio (v/c) approaches 

 1.0, extreme congestion sets in with long 

 backups at signalized intersections. 

 While the v/c ratio is not used to define 

 level of service, it is helpful to 



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