Dr. Gridlock

Oct 21, 2013

The Washington Post's Dr. Gridlock, Robert Thomson, will be online to take all your questions about Metro, traffic throughout the region and other transportation issues.

Welcome, travelers. You've already submitted questions on traffic, transit, biking and walking issues. I want to start with a driving issue that generally draws many comments.

On my morning commute, I take US-50 to I-66. There is a message board on US-50 as it passes Fair Oaks Mall that usually shows the travel time/distance to I-495 via I-66. Most mornings, the estimate seems low. If the sign says that the travel time is 10 minutes to the Beltway, should I start the clock as I pass under the sign or does it start when I actually get on I-66 some half mile further? Maybe it is based on traffic already on I-66 going under US-50 and not the traffic trying to merge onto I-66.

Many drivers are puzzled by the travel time signs that in the middle of rush hour say something like, "12 miles, 12 minutes." And you look at the traffic around you and think, "How is that possible?"

Answer: I have no idea. I don't always go the 12 miles or whatever distance is being evaluated, but traffic would have to get much better within a few miles to make up for what I find myself stuck in at the moment.

I've experienced this on I-66, just as the commenter has, but I've also experienced it throughout the Northeast on longer driving trips.

The place where personal experience come closest to what the signs say: I-95 in Connecticut.

Virginia and many other jurisdictions use traffic data services, like INRIX, to supply travel speed information used for the dynamic message boards. Much of that speed data comes from truck fleets that allow collection of GPS data on their travel times times.

That's not the only element in the calculation, but it's a major one.

My guess on this: At any given moment, the number of GPS units feeding information may be limited. Also, it may take time for the data flow to catch up with reality.

Or: The information on the board may be accurate, but we may be caught in a jam on one segment of the measured route.

But I must say that during the morning rush, I would be amazed to find I-66 drivers traveling between Route 50 and the Beltway in 10 minutes.

How nice to read the article yesterday on Ken Schantz, the 35 mile bike commuter. While I only need commute 5 miles each way I do share with Ken the joy that comes with commuting by bike. It's getting better each year as cars get more used to bike commuters (and on my route they are by and large respectful) and more bicycle infrastructure gets built like the DC cycle-tracks (seems like very cost-effective transportation spending). Mostly, though, whether in warm weather or cold, by bicycle I get to work exhilarated and I so look forward to the commute home at the end of each day. It's a very nice way to feel about a commute.

I admire what Ken Schantz, 62, is doing on his commute between the Mount Vernon area and Rockville -- and the fact that he's lost 25 pounds doing it. Lori Aratani profiled him and his trek in Sunday's Post.

I also admire the people who have figured out that it's possible to walk a few miles to and from work. More power to them, too.

One comment I think readers will debate: Whether the cycle-tracks are cost-effective transportation spending. I say yes, if you think long range.

My apologies if this is a dumb question, but it's something I've been wondering about for awhile. I remember when it came out a month or two ago that several of the red line stations in Montgomery County (Friendship Heights and Medical Center were the two most affected, I think) needed huge renovation work done because of constant leaks in their infrastructure. Would that also be the reason for the constant water dripping at the top of the Bethesda station's entrance escalator? It's really strange--looks like it's leaking through some kind of uncovered insulation, and some days (regardless of the weather), it's almost like walking through a mini rainstorm. Can you explain where it's coming from/what it is? I'm sure it's nothing harmful, but the idea of getting splashed by "metro water" is still a little gross...

Wherever that surface water might be coming from, I think it's a different issue from the tunnel leaks, which are deep underground. Probably easier to fix, too.

I have noticed that the relatively new signs at the Farragut West metro stop do not have directions to tell passengers which way is 17th Street and which way is 18trh Street. There is alot of other info on the signs, but I think putting the direction info would be helpful. I hope this is not true at all stop.

I'm asking Metro about this, because we're seeing new-style signs at many stations. Please let me know what you see, but here's what I've noticed at several stations: The signs on the tunnel walls now mark which stations are down the line on that side of the platform, but they no longer have the arrows pointing which way to which streets. Meanwhile, other platform signs are being installed that indicate the streets reached via different exits.

Dr. Gridlock, How bad is the situation going to get on I-395 with the construction of the 95 Express Lanes? Once a month, I have to get from just south of the Mixing Bowl to Capitol Hill, and I normally take 395 and get off on Washington Ave SW, then take a left to Independence, and take a right to go to where Pennsylvania splits off.

I think the spot we'll want to watch is on the southern part of your trip, around Edsall Road where the express lanes will end.

North of that, the HOV lanes will continue, just as they do today. But toll-paying drivers who don't have enough passengers to qualify for the High Occupancy Vehicle lanes will have to exit onto the regular lanes at Edsall Road.

That could slow traffic, but I'm not sure. I think it will depend on how many drivers are willing to pay whatever the variable toll turns out to be at rush hour.

This may sound like a silly question, but when is a pedestrian considered to be in the crosswalk? Is a person on corner still on the sidewalk waiting to cross considered in the crosswalk or only once they begin walking? For the most part, I only encounter crosswalks at intersections with either stop signs or traffic lights. There are a few places that have a crosswalk in the middle of a long block and it is these that I don't know how to handle. It is one of those things if traffic is going 45 miles per hour and nobody is stopping/yielding it is difficult to know there is a pedestrian waiting to cross until it is too late. Once they start to cross, it is much easier to see, although there are times with vehicles parked on the stree that you still don't see them until they reach the main lanes of traffic.

Drivers often ask about this. The region's traffic laws refer to pedestrians "in" the crosswalk. And when I ask law enforcement officers about it, they tell me that the burden is on the driver when the pedestrian is in the act of crossing -- not standing on the sidewalk contemplating the possibility of crossing.

We can make this common interaction even more complicated: Traffic laws put a burden on the pedestrian of giving the driver a reasonable chance to stop. (You can't step out right in front of a car and expect the driver to stop.)

Pedestrian safety experts point out to me that multi-lane crossings are particularly dangerous for everyone. From the ped's point of view: So one driver stops for you. Does that mean the drivers approaching in the other two lanes are going to stop? Can the walker even see the vehicles approaching in the other two lanes?


Do you know what the issue is with Yellow Line train arrival times often not appearing on station signs until the train is a minute or two away, while the Green or Blue arrivals at the same platform are displayed as expected? For example, the sign will show a Green Line train at 5 minutes and another at 20, and not the Yellow Line arrival in between. It has been like this at Gallery Place (and other stops) for as long as I can remember.

Well, for one thing, it's a primitive system that should be replaced. It doesn't take much to fool the little computer brain behind the platform information signs.

I think problems such as you describe show up most often at stations near where trains join a line.  Another issue that sometimes comes into play is the fact that the signs can't show more than three incoming trains.

Schedule disruptions also seem to be a factor in throwing off the train arrival displays.

I disagree with your assessment regarding the ever growing back up where the express lanes end on the inner loop of 495. i've been driving this route for 25 years and it has definitely worsened with the opening of the express lanes. It's so bad now I get on the express lanes at Tyson's Corner Mall just to get a half mile ahead of the back up. Even though it's not a great deal of traffic getting back on the main lanes of 495 it's enough to make the congestion worse.

First, my assessment: I hate left-side entrances and exits on highways. It's difficult for entering drivers to look over their right shoulders for oncoming traffic, and it's difficult for the oncoming traffic, since that's supposed to be the fast lane and the entering drivers are most likely going slower than the traffic already in the lane.

My own experience with the express lanes exit into the regular Beltway lanes north of Tysons: I haven't encountered a problem there so far beyond the normal safety issues of merging into the left-most of the four lanes.

Maybe some day if the express lanes become more popular. But right now, there seems to be a much greater volume of traffic entering the regular lanes from the Dulles Toll Road.

If the express lanes merge had caused traffic to worsen significantly, then I think I should be finding traffic flowing much better once I got north of that point. But that isn't the case. At rush hours, I find traffic very slow going up to the Legion Bridge, across the Legion Bridge and up to the I-270 split. Just like it was before the express lanes opened in November.

My feeling on travel time signs on roads I drive frequently is that I'm less interested in whether the number is accurate than I am in knowing what number is usually posted on the sign. In other words, if I know that a particular sign normally reads "12 minutes," when I see that sign saying "24 minutes" I interpret as meaning "slow traffic" and I find another route. Doesn't matter if the "12 minutes" is usually wrong and it takes me 20 minutes, because if the people who operate the signs are saying it will take twice as long as their normal estimate, that seems to me to suggest heavy traffic. (I'm less interested in the actual number because that can be wrong for any number of reasons. I believe they will not post a travel time that involves exceeding the posted speed limit, but I know if the Beltway in PG County is clear I'm not going to be the one creating a hazard by crawling along at 55 mph.)

I like this practical approach to sign interpretation. Look for something out of the ordinary, which would indicate trouble ahead, rather than using the sign as an exact measure of your travel time.

Once, on 395 South, the sign indicated it was a 1 minute trip to go 12 miles to the Occoquan. I'm not sure about the Dr's car, but mine for sure cannot go 720 mph!

I can assure you my 1997 RAV4 is not making the leap to hyperspace.

Has Metro decided how much to reduce rush hour service from Vienna in order to accommodate the Silver Line trains, as both lines need to use the Rosslyn tunnel? When will the Silver Line be running?

When the Silver Line opens early next year (no exact date), you should see Orange Line trains every six minutes at rush hours. No more Rush Plus on the Orange Line.

This will be an issue if you're boarding station is between Vienna and East Falls Church, where the Silver Line joins up. (The Silver Line also will be running trains every six minutes at rush hours.)

Please keep sending in your Silver Line questions. We've written a lot about the new line, but there are bound to be some very practical questions riders have that we haven't gotten to you. Send an e-mail to me any time at drgridlock@washpost.com.

While the signage I've seen is informative for those not familiar with the system, I don't think anybody bothered to consider where the signs were placed. For example, there is a new sign across the escalators at Farragut North. These tell riders which street they will be exiting if they take the escalator. However, if you are not near the center of the platform, these new signs block the "next train" arrival signs. I assume there's no chance of metro moving one of the signs?

I regularly bike-commute on the Capital Crescent trail, and I was confused by the story in Sunday's paper about the guy with the 2-hour-plus bike commute. It said he lives in Mount Vernon and commutes to Richmond -- is that right? If so, how is the Capital Crescent part of that commute? I found the story very confusing in terms of describing his route.

Now, that would be a bike commute I'd love to hear about -- Mount Vernon to Richmond. Get to work and turn right around for home.

(It was Rockville, not Richmond.)

I completely agree with the earlier post about how exhilarating it is to bike commute. I commute 11.5 miles each way, and after a tough day of difficult meetings, it's so great to get on your bike and head home, even if it's 90 degrees outside! Metro is great to have, but nothing beats the bike commuting.

For those thinking about joining in, the Confident City Cycling course may help.

The parking garage at F-S is always so much more crowded on rainy days and I always wondered who the extra people were (cyclists (understandable), bus riders who don't want to wait for the bus in the rain, drivers who don't like to drive in the rain, etc.), and if drivers, why they don't normally take the subway if it is a viable alternative. Any clues?

I think all your guesses are good. With the drivers, they may be making a very reasonable calculation that the traffic in the core will be much worse than normal and that they'll wind up saving time and hassle on the last part of their commutes.

Many of the region's traffic experts tell me that nothing contributes to a bad rush hour as much as bad weather -- even a very little amount of rain.

Has there been a change in policy on the Express Lanes that I'm not aware of? Admittedly, I don't use them often, but I've seen 18-wheelers in the lanes on multiple occasions over the past couple months, and the police presence in the lanes is not what it used to be. Are vehicles with more than two axles allowed in the Express Lanes now? Or do I happen to see drivers cheating the lanes more often than is the norm?

No change in policy on 18-wheelers in the express lanes. That's illegal.

With the state police, they have a contract with the express lane operator. I don't know of any change in that either. When I use the lanes, sometimes I don't see any police cars. Sometimes, I see three.

I'm pretty sure I know why that garage fills up on rainy days. Metro has a deal with Springfield Mall allowing Metro riders to park in the Macy's garage on certain levels (the ones without direct mall access) because the Macy's garage is never full. A lot of people do that to save $4.75 a day and then they walk to the Metro. Makes sense to save $23.75 a week! But when it rains, I'm pretty sure quite a few of those people park in the Metrorail garage instead because it's just a long enough walk from Macy's that you're likely to get pretty wet.

I preferred the older tunnel-wall signs that indicated the exits in the Metro stations. As the train was pulling into the station, I could look at those signs easily and know right away which way to walk to the exit. That way I didn't look too "touristy" or unfamiliar with my surroundings (a good thing for someone walking alone) and could walk confidently to the appropriate exit.

Funny the crosswalks across multiple lanes of traffic came up, because I was just thinking about that. There are several random crosswalks in Silver Spring that cross SIX lanes of traffic- the ones that come to mind are on Georgia Ave and 16th St, and one near the library on Colesville Red. I get that pedestrians need a place to cross but this seems unnecessarily dangerous. I'd prefer that a stoplight was put in at these places that pedestrians could call for the signal manually. I never know what to do if I see a pedestrian wanting to cross because no one else is stopping.

I think it would be safer NOT to have the crosswalk on Colesville by the library. The only thing it can do is give pedestrians a false sense of safety.

I recall asking the Maryland State Highway Administration about that crossing a few years ago, when a reader inquired about the possibility of installing a traffic signal. The answer was that on balance, it's not a good idea for safety or traffic flow. Colesville is such a high volume commuter route, that it would be better to have pedestrians go down to the traffic-signal controlled crossing at Spring Street.


I think the other problem with trains not showing up on the signs is that, during rush hours, the trains turn around at the Mount Vernon Square station -- they go off the grid, if you will. It's not until they start back toward Gallery Place that the time pops up.

Good point. Even on the Red Line, the only one that doesn't share tracks with another line, riders experience this, because of the turnbacks at Grosvenor and Silver Spring.

This has been true since the signs went into service. At Gallery Place the train doesn't seem to show until it is actually moving toward GP. Sort of the same at Braddock Road where it doesn't show until it starts moving from King Street. If there's a huge gap between green (at GP) and Blue (at BP) trains, you know a yellow line train falls in there someplace.

I've experienced issues with the signs at King Street, because of the Blue and Yellow lines coming together. To me, it was a Rush Plus issue. King Street is a point where a morning rider might need to know the upcoming gap between Blue Line trains, to figure whether it would be better to get on the next Yellow Line train instead. But you can't always make that call just be looking at the platform sign.

Could the Yellow Line sign issue have something to do with the pocket track north of Mount Vernon Square? If a train ends its run at Mount Vernon Square, it will "turn around" by going into the pocket and then waiting for its turn to go the other way. As long as it's in the pocket, it won't appear on the arrival signs.

Yep. If you want to maintain a sunny disposition, just think of it as a bonus train. But I'd rather see the current train information system replaced with a 21st Century version.

The issue you cite about some drivers not stopping is a serious problem. The other day I slowed down to stop for a guy who was about to cross the approach road to Memorial Bridge as I was coming from I-395. You probably know the spot, just south of the circle on the "Virginia side" of the bridge, although you're actually in DC there. The speed limit is 25, but nobody goes that slowly. Anyway, I slowed to stop just as the guy to my left floored it. The pedestrian quite wisely didn't step out when he saw me stopping, so the guy behind me honked at me because the way was clear. I know I did the right thing, but man, sometimes you can't win. I do have to say this, though: If I'm faced with a choice of not yielding to a pedestrian or getting rear-ended, I'll opt for not yielding to the pedestrian every time....plus if I get rear-ended, my car might then slam into the pedestrian anyway!

If the pedestrian or cyclist isn't in the crosswalk you don't have to stop. It's just not safe for you, the pedestrian or other drivers.

The driver behind you is what traffic experts call a jerk.

Drivers should be do the speed limit, maintain a safe following distance and be prepared to stop.


Metro has implemented a new policy that does not allow riders to exit with a negative balance. While that is fine, the fare adjustment machines do not accept credit card. Are they planning on adding a credit card feature to these machines, or replacing the primitive, ugly, bulky fare machines in the near future?

The negative balance limit dropped to $1.50 when Metro lowered the price of a SmarTrip card to $2. The negative balance policy is to prevent cheating, which as the commenter says, is fine. But the fact that the Exitfare machines don't take credit or debit cards is a problem. (They take $1, $5 and $10 bills and coins.)

I don't believe Metro is going to upgrade the Exitfare machines. All the talk is about bringing in a new generation of fare payment technology that will let people pay with smartphones, credit cards or debit cards right at the fare gate.

You noted: "If the pedestrian or cyclist isn't in the crosswalk you don't have to stop." I know. The thing is, though, that area is so busy that if someone doesn't take the initiative to stop for a pedestrian who's waiting to cross, the pedestrian will never get to cross. It goes to the point you made earlier about the pedestrian having to give the drivers reasonable time to stop. A pedestrian often cannot safely step out there at all unless the driver is stopping. So, as a driver, I try to think of it from the point of view I'd have when I'm walking somewhere. I'd appreciate it if someone helped me out when I want to cross, so in that situation I'll try to do the same for someone else within reason.

I know your goals are courtesy and safety, and that you're doing something that's too rare: Thinking about an interaction in traffic from the other traveler's point of view.

Both pedestrians and drivers have been injured in crashes at that crossing. The only really safe thing would be to separate the roadway and the trail.

If you're a regular rider, you can set your SmarTrip account so the card is auto-charged when the balance falls below $10. Then, you don't have to worry about the balance going negative and having to use a cash-only machine.

Yes, I did that recently with my SmarTrip card. So far, so good.

Travelers, thanks for joining me today. I'm going to go out and eye some of the station signs we've been talking about today and will write about that on the Dr. Gridlock blog.

Thanks for all the good questions and helpful comments. Stay safe out there, and rejoin us next Monday.

In This Chat
Robert Thomson
Robert Thomson is The Washington Post's Dr. Gridlock. He offers therapy for that most intimate relationship: the one between you and your commute. You can read his work on his namesake blog, as well as in the Metro section of The Washington Post.
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