Talking Traffic

Last week I blogged about the Northside HOV Exit in Atlanta where the Bluffton University bus crash occurred. Since then, the Georgia Department of Transportation has installed some new pavement markings. Let’s take a look!

You can see the most obvious new feature for pavement markings in the images above. The giant Interstate 75 shield that has been placed on the roadway was a shock when we first drove over it. It’s not something I’m used to seeing on the roadway. I don’t know the exact dimensions of the shield, but it looks to me like nine feet wide by twenty feet long (or so). The Large SOUTH pavement marking is also new, leading up to that shield.

Another new pavement marking installed is the EXIT ONLY words and attendant raised pavement markers just on the left side of the dotted yellow stripe. You can see the white stripe, although you can’t read the words, in the second picture above. This is new.

Everything else you see has been in place for over a year. If you click through to the Flickr page on this photo, I’ve notated everything.

In the next few months, new overhead signs will be going up which will be in line with the MUTCD¹.

Will this additional striping prevent all future accidental exits here at the Northside Drive HOV exit? I don’t think so. At least, not 100%. It will help; that I do not disagree with. Hopefully it will help enough to prevent another Bluffton.

¹: There have been some significant changes in HOV-related signing in the past few years, significantly affected by the Bluffton crash. If you want to read the true skinny, go to the Manual on Uniform Traffic Control Devices (2003 Revision 2) and read starting at section 2E.59. Also be aware that another significant revision to the entire manual is under work, slated for publication this year.

You may recall from March 2007 the Bluffton University baseball team bus that mistakenly exited the interstate in Atlanta on a left-hand ramp, failed to recognize the stop condition at the top of the ramp and crashed through the barrier wall on the opposite side of the cross road, falling to the interstate and killing seven.

It has happened again, thankfully without any crashes or injuries. A bus driver thought that the left-hand exit was a continuation of the through lane and took the ramp, but the increased signage, striping and raised reflective pavement markers brought to his attention that he should stop.

The question here is, what to do? You might think from that AJC story I linked that the Georgia Dept. of Transportation is being lackadaisical about this problem, but I assure you they are not! I don’t have any good before/after images of the exit ramp signage and striping but if you were familiar with the road, you’d realize that it was a night and day difference. And there is a project in the works to put in large overhead guidesigns at all of the HOV exits around town.

Yet despite the extremely over-signed-and-marked left-hand exit at Northside Drive, another bus driver made the same mistake. Why?

From my own experience driving that stretch of HOV lane, it’s easy to see how you might do it. The road is in a slight left turn at that location and if you are following the left edgeline, you might just drift into the exit lane and proceed up the ramp. GDOT has used a dotted white stripe to indicate that the edgeline continues across the ramp exit, but I can still see how the mistake might be made.

However, let’s not forget that despite the driver error in this case, the signage was sufficient to alert him to the dangerous condition and the bus was stopped safely at the stop sign. I think that’s a win, don’t you?

171,000 vehicles per day passed this spot in 2007, according to GDOT’s coverage traffic counts. Extrapolating that to today means 124 million vehicles have gone through. Using some guesses of 0.5% bus traffic and perhaps a third of those using the HOV lane, that means 208,000 buses have passed this exit and only two (that we know of) have incorrectly evaluated the situation. That’s 0.0009 percent of the buses making a bad call.

Could this ramp have been designed better? You betcha! Are signs and striping going to “solve” the problem? Probably not. Unless you define the problem as “keep people from dying by driving over the top of Northside drive bridge thinking it’s I-75″. That I think is already solved. If you define the problem as “keep people from taking this ramp, thinking it’s I-75″ then I expect to hear of more cases in the future.

Topics: Signs and Striping on our Nation’s Roads. The National Manual on Uniform Traffic Control Devices (MUTCD)

 

 Episode 9 - Signs, Striping, MUTCD [13:52m]: Play Now | Play in Popup | Download

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