Posts about Traffic

After 25 years, Montgomery's APFO has not delivered the traffic relief it promised. Over the years, it has been revised again and again to fix the most obvious defects. But because the underlying error is never corrected, it keeps getting more complicated—to the point that now almost no one can understand it.

The law is now up for renewal once again, and the Planning Board will hold a hearing today. A 179-page staff report proposes dropping the development moratoriums. Instead, staff recommend taxing developers to build more roads in high-traffic areas and run buses more frequently.

Band-aids don't cure the disease

Such tinkering does not fix the fundamental flaw in the concept of APFOs. It's like keeping the leeches and putting band-aids on the bite marks.

The Montgomery planners started out, the first page of their report tells us, by asking how more "needed transportation infrastructure" can be built. In the back is a long list of "needed" roads, copied out of plans drawn up years ago. That puts the cart before the horse—what is a transportation planner's job, if not to figure out what transportation infrastructure is really needed?

That's also not the question concurrency promised to answer. The concept was sold to the public as an answer to "How do we get rid of traffic jams?" That is surely a better question than "how can we build more roads," though still not the right question to ask.

There's only one way to actually reduce congestion: price it, with a congestion charge. Cities like London and Stockholm charge a daily fee to each car that drives into the congested district during times of heavy traffic. (People who live inside the congested zone are usually exempt.) Montgomery could ensure its roads flow smoothly by assessing a fee on drivers who enter any of its 33 "policy areas" which fail the annual traffic test.

But this is not the cure for what ails Montgomery County. Congestion charges make sense in places where the fee is voluntary, because you don't need a car to get around. That's not the case in the cul-de-sac subdivisions of American suburbs, where you are stuck at home if you can't afford to drive.

Smooth flowing traffic is not the goal; mobility and livability is

Instead of asking how to get rid of traffic, we should really be asking, "How can we make it easier to get where we need to go to live our lives?" After a century of sprawl, it is clear that this question has no answer in suburbs that were designed for automobile-dependence. Only where people can accomplish their everyday needs without being forced to drive can people be free of traffic. That requires mixed land uses, closely spaced grid streets, rail transit, and roadways shared by drivers, cyclists, and pedestrians.

Today's suburbanites are trapped in a vicious circle. Development requires more roads and the roads create more sprawl. Each time around, the highways get more expensive to build and the traffic is worse. Transit requires ever larger subsidies to compete with subsidized car trips to low-density destinations. And APFOs only dig us in deeper.

There is no way out of this morass until we recognize that the old suburban model has failed. Montgomery County understood the need for a new direction when it adopted the visionary White Flint master plan two years ago. To make that plan work, planners had to junk their old APFO mindset in one section of the county. All leaders should take that lesson to heart, not just in Montgomery, but in suburbs everywhere.

With a design like this, there probably aren't very many people about on foot. I doubt the designers responsible for this, er, eyesore set out to deliberately put up barriers to pedestrians. So how did this situation happen?

In all likelihood it came from adhering to the letter (but not the spirit) of rules about design. When this intersection was rebuilt for the Target, crosswalks and pedestrian signals were included. That was likely done due to a statutory requirement.

The Americans with Disabilities Act requires that new crosswalks have wheelchair ramps to allow mobility challenged pedestrians to mount the curb. Unfortunately, in this case, grading for the adjacent building pushed a slope right up to the curb. Installing the curb ramp meant making the slope steeper, and the engineer would have referred to a design manual that called for a retaining wall.

The retaining wall was designed only to cover the minimum required area. In this case, that means just the wheelchair ramp. And the result is a wheelchair ramp that is a complete waste of resources, because it's entirely unusable not only by handicapped pedestrians, but by able-bodied ones as well.

And of course, even on the other 3 sides of the intersection, none of the crosswalks are linked to sidewalks. If they're ever installed, this intersection will be ready for pedestrians, with walk signals and painted lines. And it would have been great for the developers of this shopping center to have installed sidewalks along the frontage.

Though that's probably not a realistic approach in many areas. Lots of suburban and exurban areas are so spread out, that even gold-standard pedestrian accommodations would see little use. But this shopping center is actually in a relatively urban area. The neighborhood to the east is dense, and most of the streets have sidewalks, though they don't link to the sidewalk-free arterial.

Of course, while I've outlined what were likely some of the contributing factors to this atrocity, the root cause is a design system which only includes non-automotive users as an afterthought.

Charles Marohn of Strong Towns does a great job of explaining this idea in the context of Springfield, Missouri's famed (at least in engineering circles) "diverging diamond" interchange.

The video was shot by an engineer showing how great the diverging diamond is for pedestrians and cyclists. Marohn narrates over this, explaining that, actually, it's a pretty poor design if the goal is to provide a pedestrian- and cycle-friendly space.

In reality, this interchange was designed to move the most cars as quickly as possible. Cars are the first, second, and third priorities here, according to Marohn. Accommodations for those using alternative modes are just ways to check off the list to make the project a "complete street."

In many cases, we've taken the completely wrong approach to planning and designing our public spaces. It's nice that Missouri's DOT put a place for pedestrians to walk on this bridge. But the whole built environment out there has so marginalized the mode of walking, that few will ever feel particularly welcome walking there.

Designing true pedestrian- and cyclist-friendly spaces means starting the design with them in mind. But in many engineering textbooks, people who don't come in cars are just afterthoughts. And the result is not particularly pretty.

The connectivity standards reformed a key mistake in suburban development: building neighborhoods composed primarily of cul-de-sacs. In many neighborhoods, there's just one way in and out for any homeowner, to one or maybe two major arterial roads.

While this gives many homeowners the ability to live on a quiet street, it creates problems for everyone. With few entry and exit points, all the traffic gets focused on single intersections at the arterials, causing significant congestion. Kids can't walk or bike to school or even friends' houses when the only route involves going out to the busiest part of the neighborhood and along a wide road designed for high-speed traffic.

And it costs taxpayers. These neighborhoods are very expansive to plow for snow and time-consuming to navigate for ambulances and fire trucks. Subdivisions in Virginia had to wait days or weeks for plowing during the major snows last year because of the way the plows had to constantly backtrack, and people couldn't get out of their neighborhoods without any alternate routes.

Older suburban areas still primarily comprise single-family houses while providing a grid that spreads traffic around and offers many safe routes for non-motorized users. Areas like Columbia, Greenbelt and Reston win constant plaudits for designing suburban areas that lack these shortcomings, with paths to walk and bike that also build community.

The connectivity rules revolved around a simple premise: Once a developer builds a subdivision, VDOT (except in a few counties) then takes over responsibility for maintaining and plowing the roads. Therefore, they should be able to require certain standards to avoid developers pushing all the costs off onto the taxpayer. The General Assembly in 2007 authorized a change, and Virginia briefly jumped far ahead of most states with this progressive policy.

Last week, however, the Commonwealth Transportation Board, a policymaking body appointed by the Governor, voted to drop the old standards, especially the "Connectivity Index" which created a score based on the degree to which a street network was connected or isolated.

Instead, they set some rules for the number of connections out of a subdivision and onto main streets. A development of 200 homes needs 2 connections, though 1 can be a "stub end" road which connects to an as-yet-undeveloped area. Each additional 200 homes will only require one additional connection. It's better than nothing, but still means a new 200-house development can have just 1 way in and out.

Also, a subdivision can add a "collector road" which gives double credit if that road is part of a county transportation plan. So a developer could build 400 houses, all on cul-de-sacs off one major road through the center, and connect that road only at 2 points to major arterials. A typical suburban house can generate about 10 car trips per day, so there will be 4,000 turning movements onto and off of those 2 arterials every day. It's a recipe for major traffic that will harm every other resident who uses those roads.

While Virginia is weakening rules to create better road networks in new suburbs, it's neglecting established areas in favor of greenfield development and traffic-inducing megaprojects. Governor McDonnell and Transportation Secretary Sean Connaughton have made it clear they don't want to contribute to the Silver Line Phase II, even if the federal government, Fairfax, and Loudon all put in more money.

Meanwhile, but McDonnell and Connaughton are eagerly borrowing money to build large freeways like the damaging bypass around Charlottesville or to push an Outer Beltway. Much of the region's future growth will happen in Tysons Corner, but it's not getting transportation improvements it needs. And transit along the Route 1/Richmond Highway corridor is nowhere on the agenda.

Virginia could get far more bang for its precious transportation buck by focusing on local street connections, and most of all repairing crumbling roads and bridges. Instead, the McDonnell administration seems bent on repeating the mistakes of the 1950s: building unsustainable transportation networks at the periphery while letting a more central economic engine sputter. Then, it was center cities across America; now, it's Arlington, Alexandria and Tysons Corner which state officials are looking past instead of toward.

Tonight is an important meeting where Virginia residents can speak up about priorities. VDOT is having a public meeting to hear input on its 6-year priorities tonight, at the VDOT Northern Virginia District Office, 4975 Alliance Drive in Fairfax. Sadly, VDOT doesn't seem to think it's a priority to locate a meeting near Metro. An open house format starts at 6, and presentations by local officials at 6:30 followed by public testimony.

Bob Chase's Northern Virginia Transportation Alliance, a group funded by greenfield developers in Virginia to lobby for roads that would feed suburban development on their land, has been pushing its members to attend and push for an Outer Beltway. Chase even argued, with an apparent straight face, that new highway lanes were more important than repairing crumbling bridges during a round of news stories last week concerning the dire condition of the nation's infrastructure.

It's important to get more residents who support good road connectivity, local street improvements, repairing crumbling infrastructure, pedestrian and bicycle projects, and local transit improvements to counter the sprawl lobbyists. If you can't attend, you can also send in written testimony at this Coalition for Smarter Growth page.

This intersection has received a lot of scrutiny lately, after a driver sideswiped a cyclist who was subsequently blamed for the incident by Arlington Police.

The primary problem at this intersection is traffic turning right from the I-66 off-ramp onto Lynn Street to head toward the Key Bridge. This traffic has a green light at the same time as the pedestrians and cyclists have the walk signal. There are two lanes of right turning cars (and sometimes cars in the third lane turn right illegally). Shifting the Key Bridge traffic to the north of the Custis Trail crossing could eliminate this conflict.

According to recent counts, the intersection sees more than 400 bikes an hour during rush hours, and that number is increasing. That is one bike about every 9 seconds on average.

My proposed redesign could significantly improve the situation for all users: cyclists, pedestrians and drivers. The numbers below correspond to the red numerals on the above graphic.

1. Split I-66 offramp: Currently the I-66 exit ramp is one lane that curves up to Lynn Street, dividing into three lanes as it approaches Lynn. The right lane is right-turn only, the middle lane is right turn or straight onto Lee Highway, and the left lane is straight only.

My proposed configuration would divide the ramp just after its split from I-66. Lee Highway traffic would follow the existing ramp up to the light at Lynn Street. Traffic headed for the Key Bridge would curve down under the existing Custis Trail ped/bike bridge over the GW parkway and then curve left to join the existing Key Bridge ramp from the southbound Parkway.

2. Reconfigure southbound offramp intersection: The combined Key Bridge ramps could be reconfigured into a 90-degree intersection at Lynn Street with a traffic light. While I proposed all three lanes to be right turn only, the far left lane could potentially allow movement onto the ramp for the northbound GW Parkway. This intersection would have no-right-turn-on-red restriction, which would eliminate the current conflict for cyclists and pedestrians also headed for the Key Bridge.

Cyclists and pedestrians could cross with the Lynn Street traffic while it has the green, and would wait with the Lynn St. traffic while the ramp traffic has the green. With three right turn lanes and no time lost yielding to bikes and peds, there could easily be an increase in capacity for cars, even with right turns on red prohibited. In evening hours, right-on-red movements could be allowed from the right-most lane only.

3. Narrow existing Lynn/Lee offramp: The existing ramp/Lynn St. intersection can then be narrowed to two lanes, allowing more space for the trail, improving sight lines, and reducing crossing distances. Both lanes would be straight only onto Lee Highway. This would completely eliminate all conflicts with Custis Trail traffic, since there would be no turning cars. Lee Highway and Custis Trail traffic would cross on the green and would wait on the red while Lynn Street traffic proceeded.

It appears that there is probably enough room under the existing bike/ped bridge to accommodate a new ramp lane without lengthening the bridge. This Google Street View shows the southbound lanes of the parkway traveling under the pedestrian bridge.

Note there is space on both sides of the lanes (the far support is about six feet beyond the stone wall if that additional space were needed.) The new configuration would have one lane of traffic traveling north as it passes under the bridge in addition to the Parkway lanes, which would be shifted into the existing median.

I paced it off, and my best estimate is 58 feet of span available between the support wall on the west and the support column in the median of the Parkway. That would accommodate three 12' lanes with 22 feet for shoulders and median. I'm not an engineer, but if that is possible, then this solution allows for eliminating the conflict without the need for significant additional infrastructure like a bike tunnel.

While this may seem like a costly proposal, a permanent solution like this one is eventually going to be necessary. The conflict at this intersection can only get worse. Bicycle use is increasing rapidly, and both DC and Arlington are promoting more cycling and investing in it with Capital Bikeshare and other efforts. As bike traffic increases, the number of conflicts with right turning cars will no doubt increase with it.

The redesign also would nicely complement the N. Lynn St Esplanade and Lee Highway/Custis Trail improvement projects that are currently being planned. A meeting on these projects is scheduled for tomorrow night.

Whatever the solution, the northern portion of Rosslyn will need major updates to its traffic patterns in order to accommodate a growing number of cyclists and pedestrians in an environment that was originally designed for the convenience of motorists.

Leave aside for the moment whether, in this era of limited public funding, the money even exists for these projects. You still run into a simple problem with these "solutions"—a focus on highway capacity expansion hasn't been effective at solving our traffic problems.

Fortunately, we don't think the situation is hopeless. It just requires a different way of thinking about the problem to get at those different results.

While we're not going to go into every possibility in this particular post, we do want to focus on the idea that smaller, localized projects taken as a whole can be better than the larger, flashier projects. Smaller projects can offer more travel options, improved livability, and better regional transportation performance for a fraction of the cost of a megaproject.

Focusing on simple projects like making it easier to walk or bike to school in a given locality, adding housing close to jobs and in commercial shopping corridors, connecting local streets, or incentivizing development at an underutilized Metro station can have a ripple effect on transportation in our region.

This is not to say that there is never a time or place for major infrastructure projects. But we can sometimes can get much better dividends by instituting common sense, smart growth solutions that give people real choices on neighborhood scale and transportation options. And we can often use our existing infrastructure instead of an over-reliance on creating something new.

To help demonstrate that, we're starting an occasional series on localized projects and themes that, when looked at as a whole, could provide real options in transportation and living arrangements. This piece-by-piece approach can improve the performance of our transportation system in the Washington region at the same time it strengthens our communities.

Our first posts will focus on smart growth in the Rockville Pike corridor in Montgomery County, creating Safe Routes to School in Fairfax County, and citizen involvement in Gaithersburg.

In the coming weeks we hope to present similar pieces from different areas throughout the DC area to highlight a range of solutions that together will offer regional benefits. Do you have some ideas of your own for your particular part or sector of the metropolitan region? We'd love to hear your thoughts. Let us hear your suggestion by submitting it as a post and we may include it as part of this series.

Roads are a very flexible form of transportation, but are inefficient in their use of space. Each car takes up a lot of room. The New York Subway's 22 tracks carry as many people as at least 167 lanes of car tunnels would.

If people drove evenly throughout the day, the road network would work optimally, but they don't. Buses and trains work better for moving people in a shorter time period to a small number of locations, because they cost more to run but can fit more people in a smaller space.

There are ways to make the road more efficient. More people could occupy each car. That's the logic behind the HOV rules and slugging on I-395 and other roads. Thanks to slugging and high bus volume, 95/395 is one of the most efficient roadways for its size in the nation (but will actually get less efficient with HOT lanes).

Instead of pushing more carpooling, VDOT actually waived the HOV restrictions on its freeways on Tuesday. That doesn't make a lot of sense. It's like they just threw their hands up and said, "Wow, earthquake! Let's just ignore everything we do to make our roads work better!"

If we knew ahead of time that we'd have to evacuate DC in a hurry one day, but didn't know when, we might actually plan for stricter HOV restrictions than usual. Take a few main arteries and make them exclusively HOV-3 or HOV-4 for the evacuation. Ask workers and residents to find "evacuation buddies" who work in the same office or live in the same inner neighborhood. These people would share the car when evacuation time came.

Once those carpools get to suburban residential areas, people will have to get home, but depending on the type of disaster, just getting everyone out might be most critical. The drivers can give rides that one time to their passengers, or they can wait in places like libraries for family members to pick them up.

Buses could also use the HOV roads, allowing them to travel much faster back to commuter lots and make a return trip to pick up even more people.

Not surprisingly, advocates for more roads and sprawl, like the Northern Virginia Transportation Alliance, immediately jumped on the issue to call for new Potomac River bridges as part of their long attempts to build an Outer Beltway. Such bridges wouldn't actually alleviate existing traffic congestion, but would instead just drive more sprawl development and make the evacuation challenge that much harder.

During the earthquake, Ezra Klein cleverly tweeted, "This earthquake has clear policy implications that back up my previously held political opinions." That's certainly true for NVTA.

I actually learned something from the earthquake that doesn't back up previously-held opinions: we can't count on Metrorail for an emergency. Especially with today's safety concerns, Metro is going to err on the side of limiting its operations in unusual circumstances. That's probably the right move if it's not a matter of life and death. But it means we need to think about evacuations another way.

We also need to think about when evacuations are necessary. Often they're not. One of the best things the federal government can do is not to send everyone home at the exact same time. Instead, the response from OPM seems to be to pull the "everyone go home" handle at any sign of trouble. We know that this causes gridlock.

DDOT Director Terry Bellamy said at a press briefing, "You can never build your way out of an event. I know there was a lot of talk about building more bridges across to Virginia, buidling more bridges into Maryland, but you never know where the event is going to occur," the WBJ reported.

Transportation Planning Board coordinator Ron Kirby told the Post, "Not only can [sending everyone home at once] not be done, we should not try it. ... If you give [people] very good timely information, they are going to make their own decisions in ways, in general, that are going to be better for them and better for the system as a whole."

Kirby also faults Metro for not communicating more; he might not have been on Twitter, because they actually did an excellent job of communicating there. They also sent multiple press releases out over their press list throughout the afternoon and evening. If you were at a train station or on a bus, was communication good or bad there?

The best way of all to get home after a major event like an earthquake? Walk or bike, if you can.

Let's say you have a road that's one lane in each direction. At one spot, it turns into 2 lanes each direction, then back to 1. What will happen?

People will speed up when the road widens, then merge back where it narrows. Merging creates "friction," forcing drivers to slow down a little more than usual and to wait for each other which can be inefficient. The end result is lower throughput overall than if the road simply stayed one lane.

This exact thing happens on the Clara Barton Parkway. There's an area just outside DC with exactly this geometry. The parkway might flow well until that point, yet during periods of moderate traffic there's always congestion right at the merge.

Sometimes an extra lane is worthwhile. Many mountain interstates widen to provide climbing lanes for large trucks, for instance. But the Clara Barton Parkway is not such a situation (and doesn't allow trucks, anyway).

For a short time I had to drive to Potomac in the evening rush periodically, and always wondered why this bizarre situation still existed. If the parkway simply remained one lane each way with the other closed, it would indeed ease congestion.

Maryland narrowed Bradley Boulevard in Bethesda around where it crosses the Beltway. The road, usually 2 lanes each way, widened to 4 and then narrowed again. Now, 2 whole lanes are marked off with stripes. That smooths traffic and also gives bicycles and pedestrians a better shoulder to use when connecting between neighborhoods on either side.

As for the FAIL Blog photo, that was on a highway in Cornwall, England in 2006. Huge numbers of drivers were descending on the region for a music festival, and officials recognized that a 2-mile passing lane would actually worsen traffic with the heavy load.

It may sound barmy but in fact it makes a lot of sense because, if it was left open, traffic from the two lanes would have to merge into one at the top. This causes a lot of aggro and a lot of stopping and starting which has been shown to delay traffic even more.

How about cutting down on the "aggro" on the Clara Barton as well?