Double Yellow Line Danger on I-170 (Updated)

In a previous post, we saw how the lane shift at Tamm avenue caused drivers to wander out of their lanes. At least they were all going in the same direction. Recent changes on I-170 near Highway 40 have resulted in two way traffic separated by just a double yellow line. Let’s see how drivers handle this situation:

In the few minutes I watched traffic at I-170 and Galleria Parkway, nearly 50% of cars in the outside lane touched or crossed the dashed white line. Fewer crossed the double yellow line, but it only takes one car to do it at the wrong time before you have a serious head-on collision (like this crossover accident on I-64 in Illinois this week). It seems that southbound drivers are approaching this area too quickly to negotiate the lane shift to the right without wandering out of their lanes.

Median Crossover GuidelinesI looked at the federal guidelines to see what they specify for such a situation. Although these guidelines are always subject to interpretation, the guidance I found would recommend use of channelizing devices instead of just the double yellow line. The figure to the right shows the guidance for median crossover on a freeway. It specifies as a standard “Channelizing devices or temporary traffic barriers shall be used to separate opposing vehicular traffic.”

Another section of the federal guidelines addresses a similar situation to I-170, but just for a total of two lanes:

When two-lane, two-way traffic control must be maintained on one roadway of a normally divided highway, opposing vehicular traffic shall be separated with either temporary traffic barriers (concrete safety-shape or approved alternate) or with channelizing devices throughout the length of the two-way operation. The use of markings and complementary signing, by themselves, shall not be used.

Tubular channelizing deviceBased on what I’ve seen at I-170, I would recommend avoiding this section of roadway until some sort of channelizing device is put into place to separate opposing traffic. The device shown at the right could be put in place with little impact on spacing. If you are concerned about this section of roadway, share a comment here, but, most importantly, let the I-64 construction team know by leaving them a comment on their web site. I will be.

Update 07/06/07:

The team at was once again prompt and professional in their response to my concerns about this section of I-170. Here’s what they had to say:

The area you describe is not a typical interstate construction zone. The freeway currently ends and begins at Eager Rd. In the current construction configuration, it operates as a typical 4-lane arterial roadway, with the double yellow line separating the north- and south-bound traffic. Traffic in this area is posted with a workzone speed limit of 45 mph. Vehicles in this section are approaching a stop or just leaving from a stop, so the interstate standards are not relevant. A channelizing device is not required for that type of roadway condition.

I agree that northbound traffic is leaving a stop and is more cautious going through this construction zone. However, it’s the southbound I-170 drivers that think they’re on a interstate when they enter this construction zone. That area around Galleria Parkway sees high speed southbound drivers, and I do think that some channelizing device would reduce the risk of a head-on collision.

This entry was posted on Sunday, July 1st, 2007 at 3:55 pm and is filed under I-170, Safety. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.

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