Level of Service Details

Level of Service (LOS) is a system developed to analyze roadways, classification of traffic flow, and traffic quality grading according to specific metrics, such as density, congestion, and the like. Generally speaking, engineers can use LOS to assess services in the asset management realm.

There are six Levels of Service, each assigned a letter of the alphabet from A to F, A indicating the most optimal conditions. There are different methods used in LOS designation, depending on the level of analysis required. We use a broad-scope approach in generalized planning, including analyzing traffic conditions across a state, identifying current problems, and predicting potential issues.

In conceptual planning, operators analyze traffic conditions in line with design and scope decisions. In operational analysis, the focus is the current or future traffic situation itself. All in all, the LOS system's goal is to help the government ensure traffic safety and reliability for all road users.

Level of Service Real World Example

The U.S. 66 Route was a big numbered highway in Arizona and was one of the most popular in the state, at times carrying at least a million passengers yearly. While it no longer exists today as U.S. 66, it continues to be used by motorists. Roadway conditions along the highway are constantly changing. Along the main street within the communities, for example, traffic is heavy because of local demand.

LOS varies from one community to another along this main route. For example, it may be at LOS D during the morning peak hour but much better during the rest of the day or on weekends and holidays. In general, the better the LOS, the more favorable the conditions are for motorists.

Significance of Level of Service

We use Level of Service to address the day-to-day challenges of road traffic, and one of its most significant contributions is accident prevention. By helping authorities determine the different factors involved in accidents, prevention becomes easier. For example, the LOS principle helps identify hazardous highways or those that are severely congested.

Generally, assigning different roads with the A to F levels helps determine where they currently are in keeping traffic healthy and hassle-free. Even in the airline industry, LOS is used to ensure that flights arrive at their destinations smoothly and safely.

History of Level of Service

The LOS system came when highways were undergoing rapid expansion because of the increase in the volume of private motor cars. Initially, the goal was to address road congestion, and people believed that expanding the freeways was the sole solution.

City planners also created a LOS system for pedestrian facilities, including pedestrian queues, stairwells, and walkways. However, the standard developed by John J. Fruin proved to be futile as engineers thought that even if they gave a busy sidewalk an F, people would still use it because they preferred sidewalks that were bustling and interesting.

Nonetheless, the National Cooperative Highway Research Program (NCHRP) is relentless in its mission to create the best LOS system for motor automobiles, bikes, and pedestrians. The ultimate goal is to allow all road users to co-exist harmoniously.