Beyond “Level of Service” — New Methods for Evaluating Streets

Streetsblog reported earlier this month that transportation agencies are increasingly aware of the insidious consequences of using “Level of Service” as the primary metric for their projects. Because Level of Service only rewards the movement of motor vehicles, it promotes dangerous, high-speed streets and sprawling land use.

The question remains: How should streets and development projects be measured?

If this is what you want for your street, Level of Service won't get you there. You need a different performance measure. Photo: ## Online##

We mentioned that some places are switching to an analysis called multi-modal Level of Service. But Jeffrey Tumlin, a consultant with Nelson\Nygaard, says there are problems with that approach as well.

Multi-modal Level of Service, he says, takes “all of the narrow thinking around delay for cars and applies that same thinking to all the other modes.” For example, MM-LOS assumes pedestrians and transit riders have the same need as vehicles: “lack of congestion,” or space between others who travel the same way.

But what works for cars isn’t necessarily what works for other modes. For example, MM-LOS views “transit crowding” as a wholly negative thing. On this measure, an infill development might be penalized for leading to “crowding,” but a sprawling greenfield development would face no penalty, since it would produce fewer transit riders.

According to Tumlin, searching for a direct replacement for Level of Service is the wrong way to go, because part of the problem with Level of Service is the narrowness of its scope.

“LOS tells us about one thing [vehicle delay at intersections], but it doesn’t tell us about anything else,” says Tumlin. “What are all of the things we want our transportation system to do, and how do we measure whether it’s doing that or not?”

Tumlin’s advice to transportation professionals and public officials is to adopt performance measures based on expressed community values as well as the specifics of the project at hand.

For example, Tumlin said if he were designing an industrial park, Level of Service for trucks might be a primary performance measure. But on a retail street where economic development is the goal, parking availability or pedestrian friendliness might be the targeted performance measure.

If women feel safe walking on a commercial street at night, that's a great predictor of retail success, says Jeffrey Tumlin. Photo: ## Loud and Saying Nothing##

“Pedestrian Level of Service and quality of service is a very complex science,” said Tumlin. “The things that pedestrians care about are comfort, the frequency of pedestrian crossings, how long they have to wait for a green. Some of the most important factors are really related to urban design and are very subjective.”

For measures like that, local governments and transportation agencies can survey local residents, Tumlin says. In fact, one of the best determinants of a healthy retail area, researchers have found, is the comfort level of women.

“If women felt safe there walking at night, [the street] was going to be comfortable for every mode, it was going to have high property values and retail success,” Tumlin said.

Ronald Milam, a consultant with Fehr and Peers, was part of a statewide committee in California that studied alternatives to LOS for Governor Jerry Brown’s Office of Planning. Milam is also the author of the e-book, LOS Gets a Failing Grade.

Most communities — even the most transit-rich, like San Francisco — continue to use Level of Service in some of their engineering, Milam says. But many California communities are bringing in new performance measures and reducing their focus on LOS.

Yolo County explicitly allows Level of Service “F” because the community prioritizes walkability over the speed of drivers. Yolo County also implemented a vehicle-miles-traveled threshold. For new housing developments, the county targeted projects that would generate less than 44 vehicle miles traveled per household per day.

One benefit of LOS is that it tells you how the user perceives the system, albeit only one kind of user: drivers. What LOS won’t tell you is how the system is performing overall.

Rather than examine LOS at each individual intersection in isolation, Milam says, the city of Pasadena looks at network-wide vehicle speeds as a leading performance measure. Network speed also tells you what you can expect when it comes to the severity of collisions, so in certain areas, like pedestrian districts, low speeds might be targeted.

Accessibility is another important performance metric. “‘How close are the things you need?’ is a pretty important thing for us to be thinking about and planning.” Milam said. “You can solve an accessibility problem with either a transportation or a land use solution.”

Measuring the vehicle mileage generated by new development is another useful metric that several California communities are using. Traditional LOS gives preference to new developments in sprawling greenfield locations because they disperse vehicle traffic over a broad area, reducing congestion at any one intersection. But add up all those developments and the effect of that strategy is to encourage more driving overall, worsening congestion. A VMT measure, on the other hand, gives preference to projects in locations that lead to shorter and fewer vehicle trips.

In short, Tumlin says, the answer is to “stop fixating on this one metric” — Level of Service.

“Transportation performance measures are very important and they need to be simple enough to be understandable,” he said, “but they need to reflect all of the goals that we want our entire transportation system to achieve.”

9 thoughts on Beyond “Level of Service” — New Methods for Evaluating Streets

  1. While I generally agree with the conclusion reached by Mr. Tumlin and others on MMLOS (to not focus on one metric), the article describes a limited scope of the methodology and application of MMLOS than is actually already in use in many cities around the country. It can, and has been defined, as much more than one metric that can much better reflect community values and preferences. I agree with the point that for too long and in too many places the focus has been on cars and V/C or delay, but I don’t think this article does MMLOS justice in places that have already done what this article describes (i.e. Fort Collins, Charlotte, and others).

  2. Access seems to be the right metric to use. Something like walk score, bike score, or drive score, but with travel times taken into account.

  3. Transit Crowding does matter?!

    Try catching a Subway on the Lex, a Bus at the Port Authority Bus Terminal or a Train at Penn Station New York!

    It’s a miserable experience that tends to lead to 90 minute + commutes on scheduled 30 minute trips.

  4. We’re not saying transit crowding doesn’t matter, just that developments shouldn’t be penalized for contributing to transit trips and rewarded for contributed to auto trips.

  5. There is so much low hanging fruit in this domain. A few years ago I could list off a dozen things that can be measured that would have a real impact. Here are a few:

    – ambient noise
    – livability surveys (a la Donald Appleyard)
    – property tax/valuation surveys
    – mode split (which means counting bus rider, bikes, and pedestrians for once!)
    – $ of city income per acre
    – $ of city revenue for maintenance per acre (actual vs. what should be done in most U.S. cities)
    -close tracking of retail, industrial, commercial vacancies

    Having design goals like: we want a neighborhood where people have 3 or more friends on their street on average, 50% of residents walk or bike commute, and property values increase by 5% in the next 3 years.

    Or: we want this area to have more people moving through it and need to pay for the projects to do that by increasing the $/acre income by 10% over the next 5 years. Noise levels and livability cannot drop during this time. Property values we want to hold steady, but they are not as important to us in this corridor.

    These types of metrics give a vision that actually speaks directly to the bottom line of city governance and political reality.

    “Councilman, your project has increased car speeds and car trips as well but we’ve seen a sharp drop-off in incidences of on-street socializing, people report fewer friends, and rates of prescription anti-depressants are up according to our survey of local pharmacies. Additionally, several local property owners along this corridor have lost tenants – we’re looking at a plunging property tax base, and this area was already under performing in $/acre when compared to similar streets in town.”

  6. I would add another point about the complex science of these measures in the pedestrian environment, particularly. Environmental quality and level of service measures are complex for pedestrians because many things matter in the pedestrian’s perspective. By reducing this complexity into 1 single letter grade, there is a great deal of information that is lost. Places such as City of Fort Collins, CO are doing an interesting approach that the pedestrian score gets several letter grades among various categories including directness (in terms of accessibility), continuity, street crossings, visual interest and safety. This measure IS NOT then collapsed into 1 score. I think this approach has value in assessing the pedestrian environment.

  7. I understand what you’re saying, but the thing is that a dumb application of level of service to transit leads to nonsensical conclusions. Namely, that it is always better to REDUCE transit use, because the lower the transit use is, the better the “level of service” would be. That’s the opposite of reality, where we want the highest possible use of transit (and then investments to provide capacity to satisfy it).

  8. Re “If this is what you want for your street”: are you asking if we want a bunch of pricy, boutique shops and pasty whites basking in the sunshine for the first time in years? Do you have mall security hidden off camera somewhere?

  9. I think Tumlin’s argument here is overstated. The Highway Capacity Manual for MMLOS for transit measures so much more than in-vehicle crowding – allowing jurisdictions to innovate several ways of ensuring new developments don’t negatively impact a transit LOS. For a list of factors that contribute to a MMLOS rating for transit, see

    The argument is well-taken: don’t focus on traditional metrics (i.e. crowding) to gauge quality of roadways. Luckily, current MMLOS standards don’t.

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