MOVING BEYOND CAR LEVEL OF SERVICE (LOS): Measurable and Meaningful Criteria for Transportation Investments, Project Designs, and Development Mitigation (revised)

Scaled from A to F like an elementary school report card, automobile Level of Service (LOS) metrics are easy to measure and easy to understand. LOS is, essentially, the average amount of delay compared to a “free-flowing” road where everyone is moving at full design-speed – congestion! It is a powerful indicator: it has a direct relationship to the quality of the user experience (the amount of congestion and “lost time”), the environmental impact (longer passage time equals more emissions), and the road infrastructure’s adequacy (the relationship of traffic volume to road capacity) – with the car-industry-pleasing implication that the key to improving LOS is increasing capacity.


For the past half century, when the auto industry was driving national economic growth, improving car LOS was seen not only as a transportation priority but as the key to local prosperity and the “good life” for upwardly mobile citizens. Raising LOS was a required goal of nearly every transportation investment and project design. Not surprisingly, millions of dollars of federal Interstate Highway research has been poured into figuring out how various road features raise or lower LOS – most of which boil down to getting rid of anything that might prevent cars from continuously going full speed such as sharp turns, adjacent distractions, crosswalks, bike lanes, and buses.

But at some point this strategy imploded as the “if you build it they will come” dynamic repeatedly filled every new road, undermining both commerce and personal life.

Today, most of us have a more nuanced view of car traffic and a broader understanding of what improves our quality of life. Moving as many cars as fast as possible is no longer the highest priority for most of us. We’ve learned that car traffic can also negatively affect a broad range of policy issues, from environmental and climate protection to community integration and neighborhood equity, from public health and safety to land use and conservation, from business growth to job distribution, and more.

But what can replace LOS? We don’t need something perfect, just something better than what we’ve got. The need to go beyond LOS when deciding between possible investments and for evaluating transportation system designs has become part of the national transportation policy discussion. Many groups have begun working on these questions: people within the Institute of Transportation Engineers (ITE), Association of Pedestrian and Bicycling Professionals (APBP), the National Association of City Transportation Officials (NACTO), the American Public Health Association’s Transportation Group (APHA), the Transportation Research Board (TRB), and others. Congress wrote in a requirement for “performance evaluation” into the most recent federal Transportation Funding Act, MAP-21. However, the regulations emerging from the Federal Highway Administration seem to focus on traditional traffic safety issues rather than picking up the policy themes of mode-change announced by the past two Transportation Secretaries.

This broadening of the decision-making and evaluative horizon makes life complicated for Transportation Planners. A senior MassDOT Engineer recently complained that the members of the Advisory Task Force for the I-90 Allston Interchange project were asking him to incorporate too many factors, saying that “we are not in the business of community development; we build roads.” But roads are a key part of community development – his comment, while technically correct, is indicative of the degree to which we’ve not yet found effective ways to seamlessly connect our policies, our transportation investment decision-making, our road design criteria, and our transportation system evaluations.



A transportation project’s impact on the achievement of policy goals depends on what is built, where it is located, how it is designed, and how far beyond the “travel surface” its scope extends – with the construction process itself having some impact as well. The combination of the broad range of policies impacted by transportation and the desire for multiple measurements for each component creates a huge number of potential investment-ranking criteria. To what extent will a possible project increase the percentage of roads (in a particular area, or state-wide, or that carry more than a specified amount of daily traffic, or…) whose pavement is in satisfactory condition? To what extent will a possible project reduce the amount of greenhouse gas emissions? Or provide improved access to jobs and services for currently underserved populations? Florida’s Expanded Transportation Performance Measures to Supplement Level of Service (LOS) for Growth Management and Transportation Impact Analysis has over 200 performance measurements.

Some of the criteria are simply gates – yes or no check offs. Others are qualitative (and sometimes subjective) ranges – a lot, a little, not at all as perceived by the evaluator(s). Best of all are those with clear quantitative, numerical measurements. And once the criteria are listed and scored, they then need to be prioritized, or weighted, and combined into an overall rank level – either ending up with a civil-service-type strict ladder of scores or with a series of “buckets” that group projects into “highly rated” or “moderately rated” with final, more political, decision-making taking over at that point.

But it is vital to list and “weight” the many possible decision-making criteria and test them to make sure they are meaningfully related to the policy goals. In addition, there must also be a cost-effective method of measuring performance either periodically or continuously. There are many desirable criteria, or metrics, for which no measurement recording technology currently exists.  Much can be learned from the growing field of Transportation-related Health Impact Assessment (HIA) reports. And Smart Growth America’s Complete Streets Alliance division has done a good job of thinking through some of these issues and has crafted a solid foundation for further development.

One problem is that once we open the door to a wider set of issues we are immediately hit by an almost infinite maze of possibilities. There are simply too many things we’d like to keep track of: not only the impact on non-car mode shares but also on economic development, public health impacts, the natural and social environments, and more.   Even worse, many of these things would be extremely difficult or expensive – or even impossible, given current technology – to measure. And an endless list is almost as useless as an empty list, too complicated to understand or effectively use for decision-making and design. (Furthermore, as concerned Transportation Planners are quick to point out, it’s not always clear what design features will translate into improved scores on many of the evaluation criteria.)


Massachusetts’ new Project Selection Advisory Council has been struggling with the need to combine simplicity with breath.   Currently preparing to release their recommendations this fall, they are focusing on seven high-level goal-categories: Safety and Security, Mobility and Accessibility, Economic Development, Quality of Life, Health and Environment, Regional Equity, and System Preservation.

The value of these categories will ultimately be shaped by the specific criteria they contain, both the goals to be attained and the specific project-design aspects that would help us move towards that goal. Understandably, but unfortunately, the Council seems to be leaving the development of most of those details to MassDOT staff at a later date. It would be good if the Council at least suggested some as examples of what they’d like to see. For example, under Safety and Security it might be useful to go beyond a simple requirement that all roads follow “complete streets” guidelines, which can be interpreted to mean the minimum possible accommodations for non-car movement:

  • What percentage of residential and commercial roads in the project will have their design speed reduced to 20 mph, in order to reduce the likelihood and severity of car accidents?
  • What percentage of roads within the project area will end up with bicycle accommodations that provide “low traffic stress” for cyclists?
  • What percentage of intersections in the project area will be optimized for pedestrian crossing via street markings, signal timing, and a regular series of follow-up adjustments?

The Mobility and Access category might go beyond a simple reduction in travel time to include:

  • How much will the project increase the number of home-to-job connections for those who live and/or work in the project area traveling by bicycle, transit, and foot?
  • How much will the project increase non-car access to medical, educational, social service, recreational, and cultural provider locations?
  • How much will the project add to the area’s mileage of non-interrupted low-traffic-stress network?

Under Economic Development, the criteria might ask:

  • Given estimated future growth of “people trips” into, out of, and within the area containing the project, to what extent will the project prioritize movement other than by Single Occupancy Vehicles?
  • To what extent does the project facilitate Transit-Oriented-Development, including bike share and bike routes as part of the TOD mix?
  • To what extent does the project increase the opportunity for the state to tap into additional sources of economic development or other types of funding?

Quality of Life/Environmental Justice can be left vague, or can be focused with criteria such as:

  • To what extent does the project reconnect neighborhoods previously cut apart by past transportation projects?
  • To what extent does the project improve access to education, training, and jobs for residents in low-income areas?
  • To what extent does the project slow or reduce the amount of traffic, particularly truck traffic, as well as noise and air pollution, in low-income areas, especially those with a relatively high number of children?

The Health/Environment category picks up some of the same themes, but applies them more broadly to the entire population:

  • To what extent does the project reduce noise, air, and water pollution?
  • To what extent does the project increase opportunities for active transportation – walking, cycling, and taking transit?
  • To what extent does the project preserve or increase the amount of and access to open space and recreational facilities?

Regional Equity comes not from having the same number of projects in each area or spending the same amount of money in each area, and definitely not from doing the same number of miles of road work in each area. Equity is about people, not geography:

  • Is transportation spending spread proportionately according to the population in the Greater Boston, state-wide Urban, and rural areas?

Finally, System Preservation needs to include pedestrian and bicycle facilities as well as roads.

  • How many miles of complete bicycle and pedestrian network will the project directly construct or indirectly create by filling in “missing links” in existing potential networks?

And, of course, it is possible to use different high-level categories: Vehicular modalities, Environmental/climate impact, Social/community impact, Sustainable economic development/freight delivery, and others. For example, within the Modal category the criteria to be developed could cover issues of safety, efficiency, and cost for each method of travel – walking, cycling, transit, and cars.   Within the Local Context category the criteria to be developed could cover the impact of a project on the neighborhood fabric and social interactions, on possible changes in surrounding property values and uses and demographics, as well as on the aesthetic shape of the built environment. Under Environment/Energy would go issues of air/water pollution, fuel efficiency, and noise. The Economic Development category could cover the triggering effect a transportation project might have on new job creation, increasing the number of home-to-job connections, and expanded access to health-promoting consumer goods.

As always, more important than the high level category titles are the Advisory Council’s as-yet-not-released specific criteria included under each of them – although the legal need to incorporate the federal MAP-21 criteria may undermine other values.


Traditionally, the starting point in transportation investment decision-making is predicting future transportation demand, a complex question. Massachusetts, and other states, run simulations, or models, based on a range of possible changes in the surrounding context: What new housing or commercial building is likely to occur? How are the workplace and residential populations likely to change: to grow larger, older, younger, richer, poorer? How much will outsiders be drawn to the area for shopping or entertainment, and how much will people in the project area want to leave for the same reasons? Given all that, testing over a set of low-to-high possibilities for each variable, how are the current modal choices of people in that area likely to change in coming years? And how does all that impact the mix of transportation facilities needed – the demand for car trips, bus rides, bicycle and pedestrian use?

Obviously, this process incorporates a lot of educated guesswork – and seldom turns out to be very accurate. Even worse, given the contemporary transportation profession’s roots in highway planning, it should not be surprising that nearly every demand forecasting model incorporates assumptions that overstate the number of cars that will appear. (In fact, car usage has been level or decreasing for over a decade, although the results were extremely skewed geographically with congested areas getting even more congested even as overall numbers declined.) In addition, modeling software is (so far) unable to reliably predict how much currently low levels of bicycle or transit use would increase if better facilities were provided, much less to incorporate cultural trends such as the tendency of “Millennials” to delay getting a driver license or enjoy bicycling riding. “Induced demand”(the way available options and context shapes people’s personal choices) and “latent demand” (the “if you build it they will come” effect) are significantly undeveloped aspects of transportation modeling.

But what if meeting what we currently think future transportation demand will be was not the most important result of a transportation project? What if it shared equal priority with improving air quality, or increasing opportunities for daily physical activity, or knitting together previously road-divided communities? We might end up with very different investment priority rankings, and very different road designs, than now usually occurs.


There are some ways to simply the decision-making. While every situation and project is unique, it is not too difficult to make generalizations about different travel modes. Improving walking, bicycling, and transit facilities tend to help achieve certain policy goals such reducing greenhouse gas and other polluting emissions, improving public health, and increasing the desirability of a neighborhood. Improving facilities for cars and trucks tends to help some kinds of business activity and increase personal travel flexibility. Depending on the way that policy goals are themselves ranked in important, a first cut for decision-making can be based on a project’s modal focus.

On a similar assumption that bike facilities have, by definition, a net positive impact on the environment and other goals in 2012 the California State Assembly passed a bill (#2245) exempting the creation of bike lanes from these requirements. (This was prompted by an anti-bike person to hold up activity in San Francisco for several years by suing to require that every bike lane be subject to a time-consuming and expensive environmental review as a transportation project.)

But most transportation projects these days include improvements to several modes – bikes, pedestrians, cars, and sometimes transit.   Digging deeper into their impact requires analyzing other variables: location (taking into consideration environmental, social, and economic factors), design (taking into account federal and state standards), scope (the direct construction of surrounding features), and construction process as well (the use of recycled materials, the impact of detours, the amount of dust and noise generated, etc.).

There are a number of efforts around the country to come up with programs for evaluating these larger, open-ended and highly recursive questions. Oregon’s MOSAICfocuses on the “social, environmental, and economic costs and benefits” across nine categories, and the state DOT’s Alternative Performance Measures is a more recent approach. STARS, coming from Portland, OR and the Sustainability Transportation Council, measures full life cycle impact. LEED-ND, developed by a partnership among the U.S. Green Building Council, the Congress for New Urbanism, and the Natural Resources Defense Council, provides sustainability criteria for smart growth. The principles developed by that National Association of City Transportation Officials (NACTO) and the national Transportation For America coalition are an excellent framework for policy making but are much too high level for project selection much less design.


Another approach to setting investment priorities comes from new ideas about determining the types of environmental impact mitigation actions that new developments have to pay for or construct. Every project – both things built next to roads or rails and the transportation surface itself – has impacts on its surrounding environment. Although potentially broad, in many cases, a major focus of the analysis and mitigation requirements were the traffic impacts – specifically the degree to which the development would add to traffic, increase congestion, reduce the car LOS at various points.

(In some jurisdictions, political leaders find it useful to deliberately keep impact analysis and mitigation requirements vague – it increases the range of what can be demanded, an opportunity that can be used for public benefit and, sometimes, private gain. But in general, there is significant pressure to make this process relatively straightforward, understandable, and easy to calculate.)

Bellingham, Washington has tried to step away from an auto-focused approach through an innovative approach that has implications for transportation investment decision-making as well. That city has adopted an innovative approach called Multimodal Transportation Concurrency. Rather than LOS projections, developers have to provide calculations of the number of additional “person trips” that their proposal will cause. This estimate is compared with the existing person trip capacity available in the surrounding roads (measured by use versus design capacity), transit system (also measured by use versus capacity), bicycle and pedestrian networks (measured by degree of network completeness). If future growth exceeds current capacity the developer has to pay for upgrades that conform to the city’s multi-modal and mode-shift goals – with creating new bike or pedestrian or even transit stop facilities significantly less expensive (and therefore more likely to be done) than new roads.   These criteria have the huge advantage of being simple to calculate and implement. However, the overall impact seems very dependent on the modal priorities of the city’s multi-modal and mode shift policy goals, which are external to the People Trip approach itself.

California, too, has theoretically changed its new development Environmental Impact analysis from car-centric to more multi-modal. However, a recent study did not “find an agency…that has stopped using auto LOS as the primary significance threshold; cities are reluctant to change because of the fear of lawsuits.” This may change: newly passed California Senate Bill 743 (2013) prohibits using automobile delay as a significant environmental impact and allows for alternatives to auto LOS in setting mitigation requirements. Some jurisdictions are beginning to base mitigation demands on the development’s impact on non-car modes – to what extent will the generated increase in car traffic make buses run slower, or add to the difficultly of walking across an intersection, or increase “traffic stress” for bicyclists? Appropriate mitigation would address these negative impacts.


Road design, which theoretically should be shaped by the same policy-based criteria as transportation investment, is often still unable to escape from its heritage in Interstate Highway movement and safety.  Despite official policies mandating greater attention to walking and bicycling, road design often ends up prioritizing car through-put and storage (parking). Significant flexibility is built into AASHTO and other Highway Design Guidelines (including MA’s). And most road planners and designers are willing to include “accommodations” for pedestrians and bicyclists and even buses and trolleys – but only to the point that it begins to violate the core imperative to maintain or improve car LOS; a point which can be very quickly reached. It’s hard to blame the planners – road designs need specifics and the only hard numbers available relate to cars.

Transportation Engineers have a wealth of professional training, peer-culture, and validated tools for making roads better for cars. But they, like the people who approve their work, often have a hard time translating non-car-focused policy goals into specific design elements – especially when faced with hard trade-offs in the use of limited street space. Including state-of-the-art facilities for pedestrians, cyclists, or buses often reduces the road’s capacity for moving (or parking) cars, making LOS worse while also violating a project manager’s prime directive: stay in budget and on time by avoiding mission creep. So the degree that the final design ends up reflecting official policy goals is significantly dependent not on the policies but on the personal beliefs (and prejudices) of the Engineers – their willingness to violate traditional norms.

And without clear, measurable goals for investment, mitigation, and design it is very hard to do post-construction evaluation: did the project move our transportation system towards achievement of major policy goals? If so, how much? In what ways? If not, what went wrong? In fact, except when embarrassed by budget or schedule overruns, few transportation agencies have any official process for collecting and incorporating feedback. Why bother – there currently isn’t much to measure beside LOS.


On the other side of the coin, there are a number of efforts to deeply explore criteria for particular areas of concern. In 2008, the San Francisco Public Health Department (not the Transportation Department!) partnered with the city Bicycle Coalition to develop a way to catalog and calculate the safety and convenience level of intersections and street segments for cycling and walking. San Francisco’s Bicycle and Pedestrian Environment Quality Indexes (BEQI & PEQI) have since been adapted, often by public health groups, in Los Angeles, Austin, and other cities. Several community advocacy groups have successfully used them to secure specific improvements. While obviously valuable, and potentially useful in identifying particularly dangerous locations for future improvement as well as providing insight on how to design travel facilities for bike/ped safety, it’s not clear how these tools help shape larger funding decisions between transit and roads, off-road paths and sidewalks.

Northeastern University Civil Engineering Professor Peter Furth has been developing the concept of Levels of Traffic Stress as a way to standardize bicycle facility planning. Peak or average traffic speed is placed along the X-axis, peak or average traffic volume along the Y-axis, the intersection of the two is labeled with the type of bicycle facility that should be required. By implication, any other type of facility would require the submission of a Non-standard Design Exception Request with associated justifications. This would enormously advance the quality of bicycle travel, and it may be adaptable for pedestrian planning as well.   But, as with B/PEQI, it’s not clear how these tools help shape larger funding decisions between transit and roads, off-road paths and sidewalks.

Both of these previous two approaches, as well as the sustainability methods described in the Proceedings of the Second Conference on GREEN STREETS, HIGHWAYS, AND DEVELOPMENT 2013 held by the Transportation and Development Institute of the American Society of Civil Engineers provide excellent guidance for the design, construction, or performance evaluation of various facilities’ effectiveness within the framework of their particular issue concerns. But these are not broad enough to shape initial investment decisions.


Massachusetts is in a transitional period. Policies reflecting the new “car is no longer king” approach – Complete StreetsActive TransportationMode-shiftSustainability PlanningTransit Orientated Design, and more – have begun getting adopted in municipalities and some states, including Massachusetts. But even though MassDOT’s leadership has a sincere commitment to progressive change, even in urban areas where these policies are most appropriate and needed, there has been only minor change in actual practice and what gets built. In the absence of a clear, easy-to-understand prioritizing system the state’s thirteen regional Metropolitan Planning Organizations (MPOs) that help decide how federal and state transportation funds are used too often fall into a pattern of deferring to the Governor’s priorities for big projects and horse-trade around who gets the rest for which local projects. And the biggest pot of transportation money, distributed to municipalities under Chapter 90 of the state’s legal code, is explicitly exempt from most Complete Streets or other non-car-related guiding criteria!

MassDOT’s new Transportation Impact Assessment Guidelines call for developers to consider walking, bicycling, and public transit as central access modes, not just as mitigation for the traffic impacts of new development, a change that WalkBoston helped push through.   But these are not even close to becoming mainstream practices.

It is possible that the upcoming public hearings of the state’s quick-turn-around Project Selection Advisory Council will shape public opinion around a broadly acceptable set of criteria, as well as providing a forum for the reconciliation of the related criteria coming from the Impact AssessmentActive Streets Recognition, and Healthy Transportation Directives.


Transportation is much too important to be left to the transportation industry. All of us have a stake in making sure that transportation system help create the type of sustainable, prosperous, and livable world we want to live in. However, without meaningful, measurable, and easily acted-upon criteria, moving from policy to reality, from the democratic oversight of government actions to the street-level impact-reality of public programs, is like pushing the tail end of a string and expecting the front edge to move.

Transportation investment needs to be shaped by the full set of policies whose fulfilment is affected by transportation: public health and safety, land use and conservation, environmental and climate protection, community integration and development, local business growth, and more. But exactly because there are so many of them it becomes hard to prioritize – especially since so many are stated in qualitative terms that are hard to cost-effectively measure.   In the absence of usable alternatives, decisions get based on the hard numbers that are available – car congestion as described by the “Level of Service” (LOS) that primarily measures the amount of delay compared to a “free-flowing” road. The importance of dealing with car traffic is further intensified by the way existing Transportation Demand Models, used to predict future traffic levels, consistently overestimate future car volume and are inherently unable to predict the “latent demand” of how many more people will walk or bike or use transit if provided excellent facilities.

This process doesn’t have to start from scratch. Some experiments are already underway. And there are some cities (and regions) whose transportation systems already seem to be moving in the right direction. We need to examine the decision-making criteria being used those cities (and regions): what tools and methods are they using to measure and collect the data? How do the criteria function within their decision-making process?

As Congress continues to stalemate on fundamental ideological difference, and because we can’t trust that the next President’s Secretaries of Transportation will be as committed to a multi-modal and sustainable future as Obama’s choices, we have to begin changing the way the transportation decision-making and project design process works.   It can be done.


Thanks to the many, many people whose ideas and comments have shaped my understanding of these issues.   All opinions and mistakes are, of course, my own responsibility.


Related previous posts include:

STEERING THE ORGANIZATION: Using Decision-Point Criteria to Achieve Goals

PERFORMANCE MEASUREMENT FEEDBACK: It’s Hard to Stay on Route if You Don’t Know Where You’re Going






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