“Level of service” (LOS) is one of the most enduring ideas in public-sector management. It started as a technical grading system for traffic flow and evolved into a broader way governments define what residents can expect from public services.
Along the way, it shaped zoning decisions, capital budgets, environmental reviews, and day-to-day operations—for better and worse.
Where LOS began
In 1965 the Highway Capacity Manual, produced under the Transportation Research Board, introduced LOS as a way to describe how roads and intersections operate.
Engineers translated speed, density, and delay into A through F grades that non specialists could grasp. Fast and free flowing traffic tended to earn higher grades, while slow and congested conditions earned lower ones. The report card format moved quickly from manuals to meetings because it made choices visible to elected officials and the public.
Cities and counties adopted LOS in their plans and codes, often as part of development review. Many jurisdictions set minimum standards for intersections or corridors and asked developers to fund mitigations when new projects pushed grades below the threshold. Florida’s concurrency era became a well known example.
LOS also shaped environmental review practice. In California, analysts long treated a drop in intersection LOS as a significant impact under CEQA, which led to capacity oriented mitigations. Public works and transportation departments used LOS to size roadways, choose signal control, and justify capital projects. In many places it became the default performance target for surface transportation.
Driving our car problems
By the 2000s, a consensus in academic and advocacy communities emerged that LOS for vehicles delay wasn’t working.
There were lines of critique:
Expanding capacity to “preserve” LOS often filled quickly, pushing agencies into expensive widening cycles with limited long-term congestion relief.
Designing for higher vehicle LOS typically produced wider, faster corridors that degraded safety for people walking and biking and undermined main-street vitality.
And a car-delay metric sidelined transit, walking, and biking, disproportionately burdening people without reliable access to a car.
Calls for moving away from vehicle delay LOS grew.
Towards fuller transportation management
Gradual reform began. Slowly, agencies started to add different measures—those for people on foot, on bikes, and on transit.
Planners tracked person throughput rather than only vehicle throughput, as well as complete streets commitments, low stress bike networks, sidewalk continuity, crossing frequency, and multimodal mitigations in development review.
Transit targets emerged for frequency, span, reliability, crowding, and access to frequent routes.
Measurement emerged for numbers of jobs, schools, and services residents could reach within a set time by different modes.
Freight and curb programs set expectations for travel time, delivery windows, and turnover.
Vision zero emerged, the target for zero deaths or serious injuries.
Climate and health objectives came to sit within LOS style frameworks, including VMT reduction, mode share, and exposure to air and noise pollution near major roads and freight lines.
Agencies disaggregated performance by race, income, age, disability, and place to see whether every neighborhood meets the floor standard and whether gaps are closing year over year.
In 2020, California passed SB 743, which shifted transportation analysis under CEQA from intersection delay to vehicle miles traveled.
Next, Federal performance management under MAP 21 and the FAST Act emphasized reliability, safety, and asset condition. The center of gravity moved from delay to outcomes that people experience.
Today, LOS for vehicle delay is still with us. The changes haven’t reached every agency, and others still use the metric but more narrowly, like for freight routes, evacuation corridors, and certain intersections.
Others continue to use it alongside other measures. Corridor planning now puts vehicle LOS next to safety, reliability, transit travel time, and access, and in many cases the people centered measures are decisive.
Operations teams monitor real time reliability, incident clearance time, and headway adherence. Equity reporting has matured as well.
Most agencies now use a dashboard rather than a single grade, and they tune targets to context. A downtown main street needs different goals than a neighborhood collector or a heavy industrial corridor.
Overall though, the importance of vehicle delay LOS has declined as its shortcomings have become more widely understood, and it is being increasingly replaced by other measures that deliver better results.
Good service now means safe, reliable, affordable, and accessible mobility for people, not only fast movement for cars.
It’s also understood that the benefits, costs, and issues around transportation are inextricably to linked land use, housing, and other disciplines and departments.
And furthermore, people don’t need transportation for transportation’s sake—it is ultimately to access opportunities and resolve needs for wellbeing, of which strategies besides transportation are available.
Beyond transportation
Meanwhile, local governments have borrowed the LOS idea for services beyond transportation.
Fire and EMS agencies published response time and coverage goals that guide station siting and staffing.
Public works tracked snow clearance time, pothole repair, street sweeping cycles, and signal uptime.
Parks departments measured access to green space and program availability. Utilities set standards for water pressure, outage duration, sewer overflow prevention, and flood risk tolerances.
Customer service teams set response and resolution times for 311.
Airports and terminals managed comfort and processing time in key areas.
In each case leaders defined the service, measured delivery, and managed to a public standard.
A language for executives
LOS has also become a language of executives. Mayors, city managers, and county administrators use it to compare priorities across departments and to focus leadership attention.
As such, it has lets transportation proposals sit at the same table as water, parks, housing, and public safety.
Departments present LOS targets with timelines and budgets, and executives see tradeoffs, assign resources, and hold teams accountable.
Chief financial officers use it to link funding to promised service levels.
Budget offices use cross-agency scorecards to coordinate action, for example faster bus travel times that require both transit priority and signal timing, or safer corridors that require design changes, targeted enforcement, and maintenance.
LOS has led to a common language that makes technical management visible at the highest levels, where decisions are made that span multiple disciplines and power exists to create shared ownership.
Looking ahead
Advocates of equitable transportation can find LOS to be a sore spot. It is one of the drivers of historic and still ongoing widespread public policies and investments that lead to, and lock in, destructive car-centric planning. So there can be an understandable impulse to write LOS off.
But its impact and power is the point. The idea of LOS is performance measurement. Its proposition is to define the service, measure it in a transparent way, and manage to a public standard.
And so what began as a traffic report card using a lot of assumptions that have needed to be updated has grown into a practice of performance management to describe what government will deliver. It has become a language that helps executives set priorities, align budgets, and give sustained attention to the work that matters.
A question for policymakers looking ahead: What are the services should we be providing now, and what are the expectations and standards that we should be committed to?
References
Litman, Todd (2024). Evaluating Transportation Equity. Victoria Transport Policy Institute. https://www.vtpi.org/equity.pdf
California Governor’s Office of Planning and Research (2020). Technical Advisory on Evaluating Transportation Impacts in CEQA. California Governor’s Office of Planning and Research. https://opr.ca.gov/ceqa/updates/sb-743/guidance/
California Natural Resources Agency (2018). CEQA Guidelines Update implementing SB 743. California Natural Resources Agency. https://resources.ca.gov/ceqa
Federal Highway Administration (2016). Guidebook for Developing Pedestrian and Bicycle Performance Measures. U.S. Department of Transportation Federal Highway Administration. https://www.fhwa.dot.gov/environment/bicycle_pedestrian/publications/performance_measures_guidebook/
Transportation Research Board (2016). Highway Capacity Manual 6th Edition A Guide for Multimodal Mobility Analysis. Transportation Research Board. https://hcm.trb.org
Florida Department of Transportation (2013). Quality Level of Service Handbook. Florida Department of Transportation. https://www.fdot.gov/planning/systems/programs/sm/los/
National Association of City Transportation Officials (2013). Urban Street Design Guide.
National Association of City Transportation Officials. https://nacto.org/publication/urban-street-design-guide/
California State Legislature (2013). Senate Bill 743 Environmental Quality. California Legislative Information. https://leginfo.legislature.ca.gov/faces/billNavClient.xhtml?bill_id=201320140SB743
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