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Redesign could improve dangerous Rosslyn intersection

The intersection of Lee Highway and Lynn Street in Rosslyn, where the Custis Trail crosses Lynn St., is one of the most dangerous intersections for cyclists in the Greater Washington area. By reconfiguring the exit ramp for the Key Bridge, this conflict could be reduced, dramatically improving safety while also potentially improving traffic flow.

Graphic by the author.

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.

Image from Google Street View.

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.

Steve Offutt has been working at the confluence of business and environment for almost 20 years, with experience in climate change solutions, green building, business-government partnerships, transportation demand management, and more. He lives in Arlington with his wife and two children and is a cyclist, pedestrian, transit rider and driver. 


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It appears do-able from an engineering standpoint - I imagine the big issue would be a political one - it appears to require the National Park Service to allow an I-66 off-ramp to run across their land.

by Chris S on Oct 4, 2011 2:23 pm • linkreport

THat isn't just NPS land. It is also a private parcel stuck in there.

by charlie on Oct 4, 2011 2:37 pm • linkreport

Chris S +1. Yeah, not going to happen if Park Service is involved.

by Paul on Oct 4, 2011 2:38 pm • linkreport

Seems like a lot of proposed changes to address what is introduced as a right-turn / ped conflict... in which case I think of an LPI. Either an LPI that gives a head-start while holding all motorists with an all-red; or one that just holds the right-turns for either a few seconds or for the minimum walk + ped clear totaling 22 seconds. Though off the top of my head, I'm also not familiar with the actual volumes of peds/bikes and turns... so I leave it open that an LPI might not be THE solution.

by Bossi on Oct 4, 2011 2:51 pm • linkreport

By the way, what's that thing that looks like an abandoned road or driveway just north of an parallel to the trail, just east of Lynn Street?

by Tim on Oct 4, 2011 3:04 pm • linkreport

Rosslyn has some terrible intersections for everyone. I know more people who walk than bike, and the crosswalks cross busy intersections where drivers don't like to stop, and where too many pedestrians like to run across them regardless of the signals. The cross walks on Lee Hwy from the Key Bridge Marriott to Air Force Assn. bldg. are particularly bad. Twice in two weeks I was almost hit by people running the red lights. I agree that Bikers need help, but even when they have separate signals, they are not obeying them. Meanwhile, pedestrians are force to cross 3 lane highways in several places in Rosslyn which still seems like it was designed more for Cars than anything else. Just some thoughts, thanks!

by BEN C on Oct 4, 2011 3:39 pm • linkreport

Steve, Great ideas. This is a tough intersection for everyone.

Is there a possible temporary (quick/cheap) solution that could change the timing of the lights without backing up traffic (bikes and cars)? For example, could there be a bike/ped only crossing period followed by a right turn arrow for cars turning onto N Lynn?

by Mitch Wander on Oct 4, 2011 3:47 pm • linkreport

Chris S hit on my only concern - NPS. That, as I understand it is the main reason the bike tunnel is so hard to do. I agree that it is a good solution, and I'd be interested in what it costs compared to the tunnel.

by David C on Oct 4, 2011 3:59 pm • linkreport

With the amount of homeless men in Gateway Park, I would not want to imagine what a tunnel would look like.

by charlie on Oct 4, 2011 4:12 pm • linkreport

This is an overcomplicated solution. A simple, nearly free solution is to create a separate traffic light cycle for the Custis trail crossing and not let is coincide with the car traffic.

I don't like Bossi's idea of giving peds and bikes a lead, because that leaves the existing conflict in place for people who come from the west because both lights go green at the same time.

On the whole, Rosslyn needs a massive traffic update, which is going to be difficult. It is heavily congested, but space needs to be found for the increasing pedestrian and bike traffic.

Also [pet peeve alert], Rosslyn needs better signage. That would help with the traffic chaos as well. There need to be clear overhead signs at every block indicating what lane to be in for US-29, I-66, US-50, GW Parkway, Key Bridge, I-395, the Reagan and Dulles, as well as the local streets Lynn, 19th, Ft Meyer, and Wilson. And any reminders for drivers that there are many pedestrians and bikers around.

by Jasper on Oct 4, 2011 4:32 pm • linkreport

As charlie noted, there's a private parcel in the middle of those trees there (and the pavement to which Tim refers is its driveway). The owner had been trying to get approval to build condos at one point. I don't know what the status of it is now, but aside from NPS challenges, there would be expense/negotiation in acquiring that right-of-way.

by RichardatCourthouse on Oct 4, 2011 4:37 pm • linkreport


Agreed the LPI wouldn't help those coming from the west if there isn't enough bike/ped vols from the east to claim the crosswalk.

But my 2nd option would still help in that regard: a ped call would hold the right-turns; the same as Mitch's subsequent comment. But this would take a greater proportion of the signal's cycle to accommodate so I'm unsure offhand what ripple effects that might cause.

by Bossi on Oct 4, 2011 4:38 pm • linkreport

@ Bossi - There already is an LPI at Lynn & Lee WB (I-66 off ramp)

by DK on Oct 4, 2011 4:40 pm • linkreport

Just for clarification in case anyone is confused, LPI = Licensed Private Investigator.

by Greg on Oct 4, 2011 4:46 pm • linkreport

In this case, LPI means Leading Pedestrian Interval.

It's where the walk sign comes on 5-10 seconds before the corresponding green ball. That allows pedestrians to be in the street before people start trying to make right turns across the crosswalk.

by Matt Johnson on Oct 4, 2011 4:48 pm • linkreport

An interesting idea. But given the level of retaining wall and grading needed for Steve's ramp idea, I would not be surprised if it were just as expensive as the bike/ped tunnel idea.

by Froggie on Oct 4, 2011 4:49 pm • linkreport

Whoa, a 10 million dollar solution to a $1000 dollar problem. Why not just retime the ped signal/green light conflict and be done with it.

by freely on Oct 4, 2011 4:51 pm • linkreport

It's where the walk sign comes on 5-10 seconds before the corresponding green ball. That allows pedestrians to be in the street before people start trying to make right turns across the crosswalk.

What good is that? That means cars will have to yield to pedestrians and cyclists in the crosswalk!


by oboe on Oct 4, 2011 5:35 pm • linkreport

I have to agree with the comments that this is an overly complicated solution to a relatively simple problem with too many stakeholders to worry about. However, elements of it could be used in comprehensive redesign of Rosslyn's transportation network.

by Chuck Coleman on Oct 4, 2011 6:49 pm • linkreport

Steve here adding some information and adding some details.

First, if you are personally unfamiliar with this intersection, there have been numerous collisions here--at least three in the last couple of months. There are literally dozens of near misses every day.

Yes, there are numerous entities here: VDOT, Arlington, NPS and owners of the private parcel. The road one sees north of the trail is actually that, an abandoned road. My understanding is that there were once a couple of single-family homes here and that the lots are still privately owned. I'm also told there are lawsuits of some kind regarding that land.

So undoubtedly this presents some implementation challenges. No more than a bike tunnel however, and although it's probably not something that could happen in 2012, it's worth having the idea out there for future consideration.

The suggestion to create a new light sequence would go like this:
- Lynn St green (trail red)
- Lee Highway green (trail red)
- Trail green (Lee Hwy red; no right turn)

A couple of questions arise.
- Since there would be a longer cycle to accommodate the trail separately, what would traffic impacts be? I suspect traffic would back up on the ramp and Lynn Street more than it does now.
- Would there be right-on-red while Lynn is green? If so, how would this be signalized to prohibit it while the trail is green but not while Lynn is green?

by Steve O on Oct 4, 2011 11:46 pm • linkreport


Some major infrastructure change will have to be made here eventually, because the already substantial bike traffic is going to continue increasing. We can either start thinking and working on it sooner or. . .

PROGNOSTICATION (Bookmark this comment for future reference):
Given the number of collisions and near misses at this intersection, it is only a matter of time until someone gets killed. Then this blog and Washcycle will explode with comments on how cyclists are just too arrogant and they think they own the road AND/OR drivers are too aggressive and/or disrespectful of cyclists rights. None of that will matter to the family and friends of the dead cyclist. He or she will be dead. Then, and only then (or it might take a second or third fatality), will the various parties finally get serious about fixing the problem.

by Steve O on Oct 4, 2011 11:55 pm • linkreport

Several good suggestions here.

The connections from the major bike trails to the bridge approaches (as well as to each other) have a lot to be desired. In addition to the problem of bad road crossings, well-documented here, signage is typically very poor. Example - try finding the southbound Mount Vernon Trail if you're coming from the north side of the Memorial Bridge, if you've never been there before.

Some other items on my own wish list:

-A better approach between the Capital Crescent Trail and Key Bridge, which does not require walking one's bike up steep flights of steps between K Street and 34th & M.

-A paved, signed path from the CCT just east of the Macarthur Boulevard tunnel, to Macarthur Boulevard at Sangamore Road, with signs marking the route along the streets of Brookmont (Maryland Avenue, Broad Street, Valley Road) down to the Lock 6 Bridge to the C&O Canal Towpath.

-A paved path between the CCT and the C&O Canal Towpath at the Arizona Avenue bridge.

-Improved connection and signage between continuation of CCT along Georgetown waterfront to Rock Creek & Potomac Trail at Thompson's Boathouse/Virginia Avenue.

by Frank IBC on Oct 5, 2011 12:29 am • linkreport

It seems the 58' may be sufficient if the 3 lanes were going the same direction, but I don't see how that could work with one lane heading north, and 2 on the parkway heading south.

by Regan on Oct 5, 2011 8:44 am • linkreport

One nice thing about this idea it would restore the ability to turn on to Ft Meyer while exiting SB GW Parkway. I never liked it when they took that away about 10 years ago. It was a confusing turn -- you had to wait for three lines of traffic - but shaved a lot of time off.

@SteveO; you make a passionate argument for road safety, but I have to think sometimes we make it too easy for drivers. However, from a safety perspective most of the accident you are descrbing come from right hand turns -- and the speed is lower. There are other parts of the GW parkway where that isn't the case, and the chance for a fatality are higher. Finally, in at least one of those accidents, the accident occured as a result of crossing the exit ramp itself -- not Lynn St -- and your proposed reconfiguraton does nothing to stop that. In fact, it just makes the second (GW Parkway and Lynn) intersection MORE dangerous.

by charlie on Oct 5, 2011 9:04 am • linkreport

Thanks, Steve O. This idea does look promising as a long term solution.

I think that the short term solution should be adjusting the signals, at least during rush hours, better signage for drivers and better enforcement from ACPD.

To charlie's point that this plan doesn't eliminate the danger of the intersection labeled 2 above - I do think it reduces the danger, by squaring off and adding a light to what is currently a curved yield.

Like Frank IBC, I would like to see a better connection between the Key Bridge and Canal Street (for CCT and Rock Creek Pkwy users). Wisconsin to M isn't too bad when traffic is either light or so heavy that it's stopped. I dream of a day when M Street is one-way Eastbound, N Street one-way Westbound, and there's a cycletrack along the West side of the Key Bridge, continuing onto the South side of M Street and connecting to bike lanes/cycletrack on Potomac Street (with a bike-only bridge), Wisconsin Ave or 31st Street. (Just imagine how much nicer M Street could be with sidewalks wide enough for the crowds...)

by GMB on Oct 5, 2011 9:29 am • linkreport

My solution does resolve the off-ramp crossing problem. It reconfigures the s-bound ramp into a signalized intersection combined with the n-bound ramp(see the #2 description) with no-right-on-red. At both intersections the perpendicular traffic would move independently. Cars would wait while cross traffic proceeded and vice versa. There would be no turning on red lights. I should have crossed off the curved ramp that goes to the Key Bridge from the s-bound parkway for clarity. That one would be replaced by the blue arrow.

@Regan. There would need to be a median and one of those stone walls separating the n-bound & s-bound lanes. I believe there is space for that. The current s-bound Parkway lanes including all the pavement outside the lane markings take up less than 30 feet. That leaves 28 feet of width to create a single lane, shy space plus median with barrier. That seems like enough to me.

by Steve O on Oct 5, 2011 9:58 am • linkreport

Here's how history can twist: The private parcel at the end of the road was taken by VDOT for the original construction of I-66. When VDOT didn't use it, the owner spent years in court and eventually managed to get it back. Several ambitious development plans were rebuffed by Arlington County and litigation over rezoning goes on. Now, if VDOT could acquire the parcel again and shift the off-ramp north about 40 feet, to the north of the bike/ped crossing, traffic conflicts would be reduced.

As for the larger shift Steve sketched, NPS representatives made it very clear during Arlington discussions about the private parcel that they would not permit any encroachment on their property and the hillside woods.

by cj on Oct 5, 2011 10:02 am • linkreport

@Steve0; that isn't "solving" anything.

You are taking away a one lane crossinng and replacing it with a signalized three lane crossing. And if you're going to go no right on red there it is going to be a problem with backups on the ramps.

There is a similar lane under the bridge at Memorial.

Another, simplier solution is to replace the Jersey barriers and weeds between the current Custis trail and the 66 exit ramp. As it is, drivers don't see bikers until they are at the red light.

Woud a red light camera help?

The biggest problem is actually the number of tourists in the entire area. Any redesign is going to deal with that.

by charlie on Oct 5, 2011 10:06 am • linkreport

Thanks for clarification on the parcel.
Somehow the ramp would have to cross the trail to get north of it. Grade separated. So a bridge or tunnel would need to be built in any case.

I have no doubt that NPS has been inflexible in the past. But as you have pointed out, history can twist. Someday they might, too.

by Steve O on Oct 5, 2011 10:11 am • linkreport

Not a chance of happening. 1. As noted a lot of this NPS land. 2. What isn't is VA state. 3. What isn't that is a piece of private property that is in heated and protracted debate with Arlington County over. The NPS will not give up any green space easily and without great debate. The cost to do this is also going to be ridiculously high for the purpose. Instead, make a simple solution: install bike/ped traffic lights crossing Lynn St. Put up "no turn on red" signs at the off ramp for I-66. Sync the existing lights with the new bike/ped light so bike/ped have time to cross without car movement in the intersection. Done.

by JorgeGortex on Oct 5, 2011 10:20 am • linkreport

Would it not be cheaper to move the bike path instead of the exit ramp? Extend the bike path along the parkway under the Key Bridge up to Spout Run, run along Spout Run to connect to the Custis Trail. This would get most bikes off of the sidewalk in Rosslyn which is a major problem besides that particular intersection.

by Clay on Oct 5, 2011 10:45 am • linkreport

Tim: There used to be an NPS maintenance yard at about the same location as the abandoned service road you saw in the aerial photo. I suspect this was the access road for the yard. Speaking of the Key Bridge exit, old timers like yours truly remember the long-gone and very scarey exit to Key Bridge from the NORTHBOUND GW Parkway: you had to wait for a break in the oncoming soutbound traffic, then gun it across both lanes of the parkway and drive up the hill. Head-on collisions were nasty and frequent.

by Publius Washingtoniensis on Oct 5, 2011 11:32 am • linkreport

The lead time of the walk signal given pedestrians and cyclists at this intersection is better than nothing, and has the advantage of being cheap. But, there's nothing to prevent cars turning right from the 66 exit ramp from ignoring the lead time, and in my experience, they mostly do.

I've crossed this intersection twice a day for 9 years as a bike commuter, and the first car on the exit ramp is ALWAYS inching forward - either trying to turn right on red, or to "beat" the pedestrians and cyclists waiting to cross when northbound Lynn gets the red light.

Besides the danger of hooking east or west bound peds and bikes on the Custis Trail, these cars block the right of way of north and south bound pedestrians and joggers (who are especially prevalent during evening rush hour) crossing in front of the exit ramp to get to and from the Key Bridge. To get around the car, pedestrians walk into traffic heading northbound on Lynn to the Key bridge. For some reason, a lot of joggers dress like cat burglars (am I right? :) ), so they're not very visible either.

Perhaps there needs to be some sort of physical impediment to discourage cars from turning right on red off the 66. Maybe even a speed bump? I'm no engineer, so I'd like to hear what knowledgeable people think.

by Pete on Oct 5, 2011 4:30 pm • linkreport

With that much cycling and ped traffic on the Custis Trail, and considering major road changes to fix issues, why not just elevate or tunnel the trail past the intersection? These type of trails are only really "safe" if they do not make any street crossings. Otherwise you really just have a sidewalk and cyclists are really in pedestrian mode.

by William Hunt on Oct 6, 2011 10:58 am • linkreport

William, there is a proposal to build just such a tunnel, but it requires using land belonging to several owners so it is just a proposal/design right now.

by David C on Oct 6, 2011 12:00 pm • linkreport

Tunnels and bridges cost huge amounts of money, logistics/engineering, and time. None of which the state is going to be interest in during these uncertain economic times. The other thing to consider is that the building of either would certainly shut down the trail for an extended period of time, which I doubt anyone would be happy with. I present, again, my original idea:

- install bike/ped traffic lights crossing Lynn St. (actually as I think about, duh, they are already there...)

- Put up "no turn on red" signs at the off ramp for I-66.

- Sync the car traffic lights with the bike/ped light so bike/ped have time to cross without *any* car movement in the intersection. Might not be a lot of time, but enough for bikes to move through unhindered.

This could be done with little to no money... just spend some time adjusting the existing timing system and install several large and obvious "No turn on red signs."

by JorgeGortex on Oct 6, 2011 12:09 pm • linkreport

Totally agree that in the immediate term, adjustments and changes need to be made (and Arlington is investigating these as we speak) to improve safety. That would include signalization and possible minor modifications to the trail, sidewalks and intersections. These will help but will ultimately be insufficient to truly solve the problem with the level of anticipated traffic in the long term.

In the long run, then, a grade-separated solution will have to occur.
@WilliamHunt - what you cannot see is the topography, which makes either a tunnel or a bridge more challenging than it would appear to be from the map. I've been told that with ADA requirements, a good deal of space would be required for either. However, either one of those would certainly eliminate the conflicts.

My idea is one solution that would not require any new major infrastructure to get the ramp and the trail on opposite sides of where they are now. It would use the existing bridge. It would require grading, paving, etc. and would cost money and presents challenging property issues. I do not deny these problems exist. I'm just waiting for the young person(s) to be killed so that the various parties will finally decide the investment to do something more substantive will be worth it.

@clay - a while back there were some design ideas thrown out to have the trail turn off behind the Marriott and curve under the Key Bridge somewhat as you suggest. There would still be the need for at least one bridge to eliminate a grade crossing at the s-bound GWP ramp.

by Steve O on Oct 7, 2011 2:11 pm • linkreport

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