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.