Level of Service (LOS) is a classification system which uses the letters A, B, C, D, E, and F to describe the quality of the mobility our transportation system provides for automobile traffic, pedestrians, bicyclists, and transit. LOS A represents the highest level of mobility, while LOS F represents the worst. The Florida DOT Quality/Level of Service Handbook uses the graphic shown in this PDF to visually depict LOS A - F for various modes of travel. LOS is closely related to the concept of capacity, which measures the quantity of traffic moving across a given point.
Measuring LOS is a complex process, particularly for multi-modal facilities due to the interaction between modes. This guide does not intend to provide instructions on how to complete the wide array of detailed calculations required to determine LOS. There are several "state-of-the-practice" resources that go into those details:
Pedestrians
Pedestrian LOS is determined by the following factors:
In areas with a significant pedestrian presence, actual pedestrian counts should also be considered.
TRB's Highway Capacity Manual provides a precedent for this approach. A variety of data is gathered for these four variables and used in a set of mathematical equations to obtain a score, which is then translated to a corresponding LOS.
Transit
LOS for Transit is primarily determined by frequency of service, as shown in the figure at right. As future MetroLink expansion considers on-street services, street car/trolley LOS will also be an important consideration. Quality and level of service for these modes also considers the type of shelters and stations provided at stops along the various routes.
Bicycles
Five key variables, listed below in order of importance,are used to determine bicycle LOS:
Like the Pedestrian LOS Model, a variety of data is gathered for these five variables and used in a set of mathematical equations to obtain a score, which is then translated to a corresponding LOS. It is important to note that the Bicycle LOS Model applies to on-street
facilities, and not pathways or sidewalks.
The Bicycle Compatibility Index (BCI) is another model that was developed to predict the overall comfort experienced by a bicyclist on a given facility. The comfort level ranges from 1 to 6, with 1 being the most compatible rating and 6 being the least/worst. The index is based on qualitative comfort measures. See the BCI summary PDF and related links for more information.
Vehicles
For arterial streets and vehicular LOS specifically, areas are of interest are divided into two categories:
Planners and designers often refer to the "design year" when considering improvements for a vehicular street. The design year represents the planning horizon for the facility. For example, reconstruction of Manchester Road today would require the examination of some point in the future to determine the types of factors that must be considered in planning and designing improvements that will serve the future needs of the facility. Planners and designers will often examine the anticipated LOS for the design year of a facility in an effort to make sound decisions about current improvement recommendations.
Future traffic estimates, land use and development projections, population growth, and a variety of other factors all go into the determination of how much travel demand a facility is expected to serve at some point in the future. These projections are estimates based on assumptions ofhowdevelopment willaffect futuretraffic. They are meant only to give an approximation of what the future condition might look like.They should be one of many factors to consider when planning and designing great streets.
It is not uncommon for planners and designers to establish a target for future LOS performance. The Missouri Practical Design Guidesuggests that LOS E be the target for vehicular capacity in the design year for the urban/suburban place types considered in this guide. This is a target, it is not a mandate. The nature of the streets that we are concerned with will inevitably present situations where it is not possible to obtain LOS E. In that type of situation, a choice must be made: add capacity to the facility to achieve LOS E; or accept something worse than LOS E because the impacts associated with achieving LOS E would be too great and counter to the vision for the place. In the end, it is a choice that planners, designers, and local leaders must make.
Efforts to improve LOS for one mode may impact the LOS of other modes negatively. Ultimately, it is the type of place and its modal characteristics that determine the outcome of the competing LOS interests. Where pedestrian mobility is a priority, such as within a downtown area, the LOS for pedestrians, bicycles and transit should be prioritized over that for automobiles.
Along highways and rural routes, the LOS for cars will be a priority and along urban arterials, where the quality and safety of travel for many modes is necessary, the LOS for all modes must be carefully balanced. The solution for any place must reflect the vision and goals for that place, as determined collaboratively by the stakeholders. Long-term plan resolution is vital to the successful development of the ultimate vision.
Characteristics Affecting Level of Service for Civic/Educational Corridors:
The rush hour characteristics of these place types present a variety of challenging elements. Employees generally arrive and leave during a concentrated time period in the morning and evening (or at the close of school), with a lesser concentration of travel occurring during the lunch hour as employees/students travel to restaurants or to run errands. In between these three peak periods, travel demand for all modes is usually less. The magnitude of the demand drop off is dependent on the other types of land uses in the area.
The rush hour peaking characteristics described above require planners and designers to have a clear understanding of the travel patternsof all modes during those time periods, bothfor existing conditions and planned future development.
For civic/educational corridorsto become great streets, they must provide safe and efficient transit and pedestrian facilities to accommodate students and employees that commute to work or school via bus or light rail and then walk to their various places of employment/education. To do so, planners, designers, and local leaders should focus on the following pedestrian measures:
Commuting to work or riding to school via bicycle is an increasingly popular mode of transportation. Such travel should be encouraged; it is environmentally responsible, reduces vehicular congestion, and is economically inexpensive for users. As such, attention to quality bicycle LOS is important. The following measures can be taken to enhance bicycle LOS in these civic and educational corridors:
Transit services are common in these place types. The presence of schools often means a significant presence of school buses. Adequate pick-up and drop-off areas should be provided off of the street so as not to degrade the LOS on the abutting street. Other transit services should consider increased frequency during the peak hours to ensure that services are reliable and that they provide enough capacity for the expected demand.
The desire for good pedestrian, bicycle, and transit LOS must not neglect the provision of quality LOS for vehicular travel. As provisions for safe vehicular operations are considered, it is important to remember that congestion is not necessarily bad. "Gridlock" and complete stoppage of traffic certainly is not good; but slower speeds and somewhat longer delays at intersections offer several important benefits to these place types:
The presence of educational facilities, especially those serving younger students, requires special attention to pedestrian provision. Pedestrian signal crossing times will likely need to be longer to provide safe crossing for smaller children.
Unfortunately, living with vehicular congestion is becoming an almost inescapable reality in our region. This is especially true in the peak hour. Our culture is predicated on social and professional structures that contribute to significant spikes in daily travel during the morning and evening "rush hour". These spikes in congestion are particularly challenging when they occur in our civic and educational corridors due to the spike in pedestrian travel often occurring at the same time as the spike in vehicular congestion. To eliminate congestion would require unreasonable amounts of money and would have damaging effects on the "places" through which the congested streets run. There are, however, measures that can be considered to improve vehicular LOS during peak conditions:
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