Are electronic signs causing Beltway slowdowns?
Ira Geller of Baltimore has noticed traffiic slowing on the west side of the Beltway each evening, and he thinks he knows why. He's not the first to reach the conclusion that electronic message signs are the culprit. As you'll see from the reply, the State Highway Administration is not dismissing his concerns out of hand. Here's what Geller had to say:
I travel the inner loop of the Balto. Beltway every weekday from Arbutus towards Towson at around 6PM. The traffic is always slow, 15 -30mph from Catonsville to Woodlawn. Motorists usually slow down to read the digital message board in front of Martin's West Caterers. Then, as soon as drivers pass the board the average speed goes up to 40 - 45 mph.
If you don't believe me, drive thru this area of 695 during rush hour.
How can we get the State Highway Administrator engineers to realize the problem with these boards exists and turn them off during rush hour traffic? Do we really need a message board to tell motorists that the traffic is heavy and that it might take a little longer to get to their destination?
Dave Buck, spokesman for the SHA, provided a detailed response. It seems thhe SHA is interested in whether its messages are always providing a service rather than a hindrance.
In general, it is difficult to know whether traffic slows because of a specific message or in this instance, because all traffic on I-70 going toward the inner loop is merging with all of the inner loop traffic right before this overhead message sign near Martin's West.
Every afternoon, traffic on the inner loop slows as the I-70 and I-695 traffic merges, then it tends to free up again toward I-795 before slowing near Greenspring Avenue. This caused inner loop delays back into Catonsville and EB I-70 delays back toward Howard County.
The brightness of the information on the sign also may play a role as at 6 p.m. in mid to late fall when it is dark, the message appears much brighter, which could cause some delay vs. late spring into summer when the sun is much higher and the sign message fades into the background more.
Overall, we have had similar questions ever since SHA began using overhead variable messages signs more than 20 years ago back -
- Does the message contain a valuable piece of information to motorists?
- Is the message clear and concise?
- Can the message be read at highway speeds?
- Is the message causing additional delay?These overhead signs are one of SHA's most visible means to convey information to the motorist while they are on the road and our goal is to make the messages meaningful and clear without causing any delay.
Over the years, we have added features included flashing beacons on top of the signs to highlight a particularly significant incident or backup, using rotating safety messages to remind motorists about certain laws, adding LED signs to replace the old style flip-disk technology, travel time messages, Amber Alerts, game-day messages, Homeland Security messages, event info, bridge height restriction info, etc...
As a side note, SHA is hoping to partner with the Univ of MD on a study to research this exact question - do the overhead DMS (Dynamic Message Signs) slow traffic specifically as a result of the message or are there other factors (merging traffic, sun glare, regular delays) that play a significant role as well. Our goal is to begin a research project with U of Md in the next year or two, if funding allows.
We appreciate Mr. Geller's email and if he is able to provide a specific date, we would be more than happy to take a look at the specific message and see if there is anything that can be done to minimize any additional delay.
Comments
When the signs provide useful information (e.g. travel times, accidents) I don't mind if traffic slows a bit before the sign. I REALLY object when the sign shows useless messages like the current favorite asking use to call (from our car?!?!?!) a TIPS line we we see anything suspicious. I fine the Amber alerts equally pointless because they are rarely targeted to a specific location but seem to be broadcast system/Baltimore Metro wide, additionally the Amber alters never seem to be in close proximity to when the incident precipitating the Amber alert occurs.
Posted by: Paul | October 25, 2010 4:30 PM
I've noticed this phenomenon many times on the northeast side of the inner loop around the Bel Air Road and Harford Road exits. Traffic always slows down to a crawl at the sign and right after it, traffic speed picks up. I personally think the signs are useless and agree with Paul's comments.
Posted by: Bruce | October 25, 2010 4:49 PM
Yes yes yes, electronic signs most definitely slow down drivers. Traveling to Baltimore City from exit 38A (Columbia) on 95 N I can always expect there to be a delay, partly because of the merging but mostly I can always expect that the traffic is due to the signs. The reason I can credit the signs for this is because after I have passed the electronic signs there no longer seems be a traffic jam, it's amazing. The signs also display the same thing every day, you would think travelers would find little need to read them, but everyone does, and the traffic is always slow. They need to be turned off during rush hour, it's pointless to tell us there is a delay ahead.. of course there is, we're in one now and we'll be in one again, it's rush hour!
Posted by: Britt | October 25, 2010 5:28 PM
As I recall, when those signs were introduced many years ago, the SHA said that they would only be used for emergencies and urgent messages because it was felt that drivers would not pay attention to them if they were on constantly.
Nowadays it seems as though there is hardly a time when they are not on, displaying something like "Report Suspicious Activity" or "Motorcycle Safety Week", if not actual traffic informaton or Amber Alerts
Posted by: Gary | October 26, 2010 12:49 AM
I will also confirm traffic slowdowns at most signs that I pass in my (admittedly limited) driving.
Posted by: Jed | October 26, 2010 12:03 PM
Using the DMS's to provide a public service message ("Report Suspicious Activity") or promote an ongoing event ("Share The Road") is, I think, useless. Traffice alerts, however, are very appropriate. Providing travel times or warning of an accident or congestion should be what these DMS's are all about. And as for the people complaining, take a speed reading course, have your eyes checked, or switch over to a secondary road and get off the Interstates. What are you going to do when satellites provide this information directly to you in your vehicle?
Posted by: trebort49 | October 26, 2010 1:37 PM
While I personally like the signs displaying the travel times or other relevant info (as opposed to generic safety messages), it would seem the easiest way to study whether the slow downs are in fact caused by slow readers as opposed to heavy merging traffic at both locations mentioned above would be to monitor speeds just before the signs and keep them blank (when there isn't actual important info to share) certain days. If there's a consistent improvement in speed when there is no message, then SHA would know to only use them for crucial info. days. If there is not a significant difference, they could go back to being used for traffic info. I do agree they shouldn't be used as SHA billboards for any old message; they should be used crucial info like delays or closures or otherwise for static messages like travel times.
Posted by: Drew | October 26, 2010 1:51 PM
With the state implementing the 511 system why do I need a sign to tell me that traffic is slow.
Also, it does not take a 'study' to figure out that these signs slow down traffic. Even when it's not rush hour people slow down 20mph below the speed limit to read them. Maybe the SHA needs to come back to reality and realize the millions they've spend on these things was for the most part a waste. They should only be turned on if the freeway is shutdown.
I'm still shocked that they think they need a study to determine that people slow down to read these signs.
Posted by: Phillip | October 26, 2010 2:51 PM
This is also a problem on 295 northbound approaching 195. You can see people hitting the brakes just in front of the signs. It happens even when there isn't significant traffic on the road. All one has to do is sit there in view of the sign and it's obvious people are braking to read it.
Posted by: BigDragon | October 27, 2010 10:29 AM