Posts about LOS Mentality

Links

Breakfast tweets: Less is more

by David Alpert   •   December 9, 2011 8:54 am

Today, we're trying an experimental format for the links: Twitter style.

Photo by xtopalopaquetl on Flickr.

• US DOT: Lowest traffic fatalities in 60 years (Transportation Nation, @marctomik)
  
• "We don't want to come off as NIMBYs." But Arlington residents don't want a homeless shelter in their backyard (Post, @_jpscott)
  
• The London Tube's central Zone 1 is very pricey, so a map shows how to get off outside and take bike share (Ollie O'Brien)
  
• What are public/private partnerships PPPs? Where are they in the US and internationally? (Brookings, @bogrosemary)
  
• What to get for the cargobike lover who has everything (& kids)? (Bike Noun Verb, @KidicalMassDC, @IMGoph)
  
• On Friday, @beyonddc exposed the folly of highway "Level of Service." Now @e_jaffe takes on local street LOS (Atlantic Cities, @vebah)
  
• An experiemental system can disable drivers' phones in the car without affecting passengers' phones (Daily Mail, Steve S.)
  
• Lance's feelings about bike lanes in cartoon form (The Onion, @JoelLawsonDC)
  

Roads

For highways, getting a 'D' isn't so bad

by Dan Malouff   •   December 2, 2011 3:25 pm

Listen to any discussion of highway congestion and you will inevitably hear about Level of Service (LOS), which assigns a letter grade to the congestion level of road segments. Letter grades start with 'A' for free flow and run down to 'F' for "failing" (congested) roads. Simple enough.

Photo by BeyondDC on Flickr.

Simple enough, except that it makes absolutely no sense whatsoever and is completely counter-intuitive.

The problem is that people hear about roads with grades of C, D, or E and think that means they are badly congested roads, because Cs, Ds and Es are bad grades in school. Traffic engineers often refer to streets with LOS D or E as "nearly failing," which sounds bad to anyone who speaks English.

But that isn't how it actually works. Any LOS above F is good. A road with an LOS of E is still moving very well.

Take a look at this year's Metropolitan Washington Aerial Traffic Congestion Survey. Download the pdf and go to its 11th page, where LOS speeds are defined. This is what you will find:

LOS A, B, and C are all free flow conditions. LOS D equates to highways moving at 65 miles per hour. LOS E is 55 mph. A highway can receive a score of LOS F - failing - and still be moving at somewhere around 40 mph.

So for the record, a highway scoring LOS D is moving faster than the legal speed limit on most highways in our region. How completely ridiculous.

Don't ever let anyone tell you Ds and Es are bad grades for highways. They aren't.

Roads

Crossing Route 7 will mean long waits in Tysons

by David Alpert   •   June 14, 2010 9:59 am

VDOT is widening Route 7 in Tysons Corner to fit in the Silver Line. New signals will require pedestrians to use two full light cycles to cross the road. This is making pedestrian conditions worse just as Fairfax is trying to transform Tysons into a more walkable place.

Photo by magandafille on Flickr.

According to Dr. Gridlock,

Because of the widening, pedestrians only have time to cross half of Route 7 during a green traffic signal cycle. The new traffic signal requires that pedestrians stop on the median, press the signal button and wait for the light to cross to the other side.

Instead of widening the major existing arterials, officials should focus on getting the street grid built so Route 7 could still fit the Silver Line without being wider. Parallel streets create traffic capacity without forcing enormous widenings. Routes 7 and 123, right under the Metro stations, will become the centers of the future walkable areas, but are already too wide to really be optimal mixed-use boulevards.

Fairfax is trying to retrofit a suburban "edge city" into an urban place at a scale never before attempted. The scale of the existing auto-centric infrastructure, such as the wide arteries and large interchanges, is the biggest obstacle. It's important the Tysons plan succeed. Virginia shouldn't make the task even harder by making the existing hurdles to walkability even higher.

Update: In the original post, it wasn't clear whether Route 7 was getting wider to fit more lanes or to fit the Silver Line. It's just adding the Silver Line, not more lanes, but the wider footprint makes it worse for pedestrians. Parallel streets could allow fewer lanes on 7 itself while maintaining the overall traffic capacity.

Roads

Loudoun blindly pushing massive, senseless road widenings

by David Alpert   •   May 19, 2010 2:17 pm

Loudoun County is pushing a plan to widen huge numbers of roads across the county, but residents are fighting back.

Keep most Loudoun roads more like this. Photo by Heather Elias.

The plan is something right out of Robert Moses' 1950s designs: Draw bigger and wider roads everywhere, at even spacing, and design completely around the needs of cars to the exclusion of people.

My grandparents used to live in South Florida (like so many others), where the entire landscape is filled with a grid of six-lane highways surrounding country clubs and housing subdivisions.

It's not a pleasant urban form, and is certainly not walkable or bikeable. It's not what Loudoun should aspire to look like.

Sadly, that's exactly what this plan envisions for Loudoun. Ashburn would become crisscrossed with six-lane expressways, between several freeways. The plan also calls for massive circumferential car capacity between Loudoun and Prince William County, despite the fact that current congestion is east-west, not north-south.

Eastern Loudoun roads in the Countywide Transportation Plan.
Teal roads will become 6 lanes, brown 8, red 10. Freeways are in yellow.

Loudoun planners, like so many others, just plugged their county into traffic modeling programs and out popped a set of road widenings. The basis of this is model is the MWCOG TPB model, which is widely criticized for having numerous flaws. It works only moderately poorly on a regionwide level, but when narrowed down to a smaller area, its flaws get magnified.

Skeptical residents hired Smart Mobility to evaluate the plan. They write,

The approach used in the CTP is one that has led our nation to spend exorbitantly on roadway construction, with the primary results being costly road improvements, induced traffic, and persistent congestion. The plan states that this approach is "industry accepted." This may have been true twenty years ago, but the CTP approach does not represent the current practice for multimodal transportation planning.

Transportation planners and engineers generally agree that this type of conventional application of a travel demand model is not appropriate for regions that are seeking to reduce traffic congestion by implementing compact, mixed land uses and street networks that provide options and ease traffic.

Smart Mobility found that the model is only about 74% accurate, and overstates the north-south travel demand by 33%. The model also assumes gas prices will remain low, which is unlikely.

In addition, Loudoun County interpreted the model in an entirely car-centric way. When roads showed up as congested in the future, they assumed the solution was to widen them. This flies in the face of the county's own Comprehensive Plan, which calls for reducing traffic through more compact and walkable development, not increasing it by paving more and more of the county.

[T]he draft CTP states that "the computer modeling exercise for the CTP only considers road segments," so it should be no surprise that the only solutions that arose from this modeling exercise was to widen road segments—with a total cost of $1.64 billion dollars.

In the real world, traffic capacity is constrained at intersections, and not on roadway segments. This is somewhat acknowledged in some of planning documents, which identify "choke points" on the region's road network (see figure below). There are a wide variety of solutions to intersection congestion beyond simply adding lanes to roadways. In fact, adding lanes to roadways can make downstream congestion much worse.

Other solutions, such as increased street connectivity that allows drivers to avoid bottlenecks and provides alternative routes for short trip, or compact mixed use development that reduces trip lengths or allows some trips to be made by walking or biking, were not considered in the CTP analysis.

New Gilbert's Corner roundabouts. Image by VDOT.

The new roundabouts at Gilbert's Corner do a better job of alleviating traffic choke points than adding lanes. Development that creates a denser street grid, instead of pushing all traffic onto widely-spaced, heavily-congested arterials, better allows for growth without adding traffic.

Loudoun should follow the Smart Mobility recommendations and throw out its existing model. Instead, the county should identify more targeted road projects that focus on bottlenecks and access to areas slated for more compact growth in the Comprehensive Plan, not long-distance commutes that only exist in such numbers in the imaginary and inaccurate world of the COG/TPB model.

Roads

Montgomery DOT rolls out another cars-first traffic test

by Barnaby Zall   •   April 28, 2010 3:05 pm

Fresh from yesterday's interesting Montgomery County Council discussion of the failed car speed tests, I received a leaked copy of the Montgomery County Department of Transportation's proposed replacement.

Rockville Pike. Photo by thisisbossi.

McDOT will announce the new policy this afternoon. The explanatory memo can be found here.

The new Transportation Policy Area Review will replace the existing Policy Area Mobility Review (PAMR) and Local Area Transportation Review (LATR) tests. These tests, which have been widely criticized, focus on how fast cars move through intersections, blocking development and imposing new infrastructure requirements whenever cars slow down.

These tests may have their places, but not in modern pedestrian-friendly plans. The reason is simple: you can't have a pedestrian-friendly community if cars move fast.

The Council wrestled for months to reconcile a pedestrian-friendly White Flint with its existing car speed tests, a struggle which was resolved only when the Council realized that the answer to congestion was not to move cars faster but to get people out of cars. That works in Arlington County, and it should work even in Montgomery County. That, at least, is the premise of the White Flint Plan.

But there's an aphorism that, if all you have is a hammer, then everything looks like a nail. That's the problem with the Montgomery County Department of Transportation, which is tasked with the huge job of handling the County's traffic problems. MCDOT sees everything in automobile terms: Rockville Pike, for example, is a big pipe from NIH and Navy Med in Bethesda to Rockville (oh, by the way, White Flint in between isn't anything at all to worry about, except if it slows cars).

Roads

Leggett wants direct pedestrian paths except when they'd interfere with traffic

by David Alpert   •   October 27, 2009 11:57 am

Montgomery County Executive Ike Leggett's isn't giving up on proposals for an anti-urban skybridge connecting the Silver Spring library to a parking garage.

Book-like facade of the new Silver Spring library.

This past weekend, Leggett unveiled concept sketches for the new library at Wayne Avenue and Fenton Street. It strongly evokes images of "an open book," along with large glass windows said to represent "the openness of government" and limestone similar to that in other Silver Spring buildings. A coffee shop and art gallery will line the ground floor, with artist studios above, followed by three stories of library. Two more floors on top will contain community meeting space and some county offices.

The design also leaves room for a future bridge across Wayne Avenue to the adjacent parking garage. Original plans contained the bridge, but urbanists protested that this costly endeavor would only draw pedestrian traffic off the surface streets, encouraging faster traffic and road designs hostile to those who wish to cross at ground level.

Existing Silver Spring plans prohibited bridges, and the Montgomery County Council voted to sustain that plan, with only Councilmember George Leventhal (at-large) voting for the bridge. Instead, to accommodate persons with disabilities, the library will contain a small amount of handicapped parking on site. Nevertheless, Leggett hasn't given up on the opportunity to put cars above pedestrians by building the bridge, and Duchy Trachtenberg might be wavering on the issue.

Roads

Lt. Gov. Brown open to new ideas, needs to hear them

by Cavan Wilk   •   August 3, 2009 11:05 am

On Thursday, July 23rd, I joined other Montgomery County-based bloggers for a conversation with Maryland Lieutenant Governor Anthony Brown. Adam Pagnucco of Maryland Politics Watch organized the forum, and MPW contributor Marc Korman also attended. Many thanks to Adam for inviting me. Overall, I found Mr. Brown to be a competent and capable person. He clearly had a lot of experience communicating with people. He was open to new ideas, but still perceives traffic through the "Level of Service" lens and traffic solutions from the standpoint of moving cars.

Maryland State House. Photo by bcostin

Mr. Brown's duties include heading up the BRAC subcabinet. I argued that planning for Bethesda Naval Hospital needs to be completely different than for a place like Fort Meade. Bethesda Naval is adjacent to downtown Bethesda, one of the flagship examples of post-war Smart Growth in the United States. It has its own Metro station. It's nothing like Fort Meade, which is located in a low-density exurban area.

When I asked why the vast majority of the BRAC infrastructure improvement funds are planned to go towards road widenings, Mr. Brown responded, "The intersections that we plan to improve are already at failing Levels of Service. We're using the BRAC funds to improve already failing intersections." I replied, "Level of Service is an antiquated, rigged metric. Cars won't do those new jobs. People will." Antiquated Level of Service metrics generate bad ideas like a new reversible lane on Connecticut Avenue, despite their poor track record in Silver Spring.

Mr. Brown conceptually supports a twin strategy of auto infrasturcture and transit for BRAC. However, I don't think that he fully understands what that means. Most people automatically assume that traffic flow is like water: widen the path and the water flows faster. They, like Mr. Brown, aren't familiar with induced demand, where a new road's very existence actually creates more demand for new roads.

To his credit, he does view additional bus service as a key tool to accommodate BRAC. But once again, he didn't seem to know what that would mean at a detailed level. Most people, including hardcore transit users like myself, dislike riding a bus stuck in heavy automobile traffic. If you want to make a bus more attractive, take it out of mixed automobile traffic by giving it its own right-of-way. Give it a time savings over the private automobile. Mr. Brown's sub-cabinet needs to revise their BRAC-oriented plans. If they're going to add asphalt to our roads and intersections in Montgomery County, they should build bus-only lanes, separated by a curb from the regular lanes.

Mr. Brown supports Representative Chris Van Hollen's efforts to secure funding for improved access to the Medical Center Metro from the eastern side of Rockville Pike. He was not familiar with the various proposals, including the pedestrian tunnel that doesn't connect directly to the Metro station. Mr. Brown said that he had not seen the engineering proposals and didn't really have an opinion, leaving the decisions up to the county and the engineers.

Maryland isn't raising its gas tax anytime soon. Mr. Brown said that both the O'Malley/Brown Administration and the legislature oppose raising any taxes while the state and nation are experiencing current crippling job losses. While it would be a good idea, such a proposal would be politically infeasible at this time, he said.

Wha about I-270? Brown reiterated the Administration's support for both the Baltimore Red Line and the Purple Line. He was also shocked to hear about the $4 billion price tag for the I-270 proposal. This issue does not directly involve his office, but Mr. Brown is now aware of this study and its potentially harmful implications.

Marc asked about MARC, which he rides regularly to commute to Baltimore from Bethesda. The Lt. Governor described long-term plans for MARC such as opening more stations and increasing parking at rural and car-dependent suburban station. He also mentioned that the funding currently isn't in the pipeline. I also praised the state for employing a "fix-it-first" policy to transportation stimulus money. It is a much better use of funds than covering more land in asphalt.

After meeting Lieutenant Governor Brown I came away with a positive impression of the second ranking executive in Maryland. While I was disappointed with some of the details of his sub-cabinet's BRAC plans, I understand that he is not an engineer or an expert in urban planning. I was very impressed with his ability to sit, listen, and absorb new ideas. Meeting with him gives me hope that our county and state can improve our plans so we can absorb all the new BRAC-related jobs in a sustainable manner.

Roads

Gaithersbungle, part 2: Old, tired formulas generate old, disastrous solutions

by David Alpert   •   July 1, 2009 9:58 am

The Montgomery Planning Department just recommended widening I-270 between Rockville and Clarksburg to 12 lanes, and adding two new lanes north of Clarksburg. The project would cost $3.8 billion, and would be a disastrous move for the County. The analysis relies on antiquated Level of Service analysis that downplays the side effects of the widening on sprawl, and ignores other alternatives such as pricing existing lanes which would alleviate congestion more cheaply and with much less damage.

Bye, bye Md. countryside. Photo by bettinche.

Widening 270 would fuel the greatest expansion of auto-dependent sprawl in Montgomery County in over a generation. In 1980, foresighted Montgomery County leaders created the Agricultural Reserve, protecting 90,000 acres of farmland in the county's rural area. They created a program to transfer development rights from agricultural land to the denser, downcounty areas, to focus growth around existing infrastructure and existing jobs.

The Reserve excludes several large areas around Clarksburg and Germantown, and as the Planning Board notes, the County has added significant amounts of new housing there, as well as in Frederick County. However, the report ignores the huge, real effect of induced demand. New lanes would spur even more auto-dependent single-family homes out in these areas, homes very, very far from jobs. The development would put pressure on future County leaders to narrow the Reserve. And, most of all, it would drive even more sprawling growth in Frederick County.

Instead of seeing freeway expansion as driving demand, the Planning Department report simply takes development as static and focuses almost entirely on vehicular Level of Service (LOS). That's entirely the wrong measure.

Planning Staff have taken a small bite out of LOS-centrism in the proposed Growth Policy, recommending a change in the standard from D to E. But if you're only designing a transportation network with the goal of moving as many cars as possible as fast as possible, you end up with distorted answers. As the saying goes in transportation planning, "If you plan for cars and traffic, you get cars and traffic. If you plan for people and places, you get people and places."

The staff report dismisses the "no-build alternative" simply because it will not relieve congestion on the roadway. But it doesn't challenge the basic assumptions that speeding the drive from Frederick during rush hour should be the County's priority with $3.8 billion.

Worst of all, the staff never consider better options, like congestion charging on existing lanes. FHWA itself concluded that charging tolls on 270 during peak periods could move enough "discretionary" car trips to other times to alleviate the congestion problems on 270. Freeways behave somewhat paradoxically, where very small changes in demand cause big changes in congestion. Brookings just released a paper recommending a road-use pricing system.

Next: Another way to improve transportation in the corridor, for less than $3.8 billion.

Washingtonian features Greater Greater Washington

by David Alpert   •   February 25, 2009 10:54 am

The Washingtonian's "Blogger Beat" interviewed me about how we can make Greater Washington greater. Here are a few the topics we covered; check out the article for the more detailed responses.

Photo by macwagen.

Three reasons Washington is great: Walkable neighborhoods (and not just in DC), Metro, and resident engagement in local government.

Three ways it could be greater: More transit, more affordable housing, and transportation departments that aren't beholden to vehicular "level of service."

How would you fix Washington's traffic congestion problem? Priority bus corridors (in the short run).

Local leader you most wish you could fire: VDOT head Pierce Homer.

Purple Line or Silver Line? Both!

The best thing Barack Obama could do for Washington is: continue moving it toward [full] self-government, including the parks, prosecutors and judges, and voting rights.