I’ve written here before about the transverse bars — which get closer to one another as the driver approaches a curve — installed on Chicago’s Lake Shore Drive to help ameliorate a crash hot spot where traditional signs and the like didn’t seem to be having much effect (for the primary reason that Chicago drivers seem to treat LSD like an Interstate highway facility). A discussion I had with CDOT some time ago seemed to reveal some early promise in the treatment, but now, the Nudge blog reports, some actual hard data is in, and the results are encouraging:

According to an analysis conducted by city traffic engineers, there were 36 percent fewer crashes in the six months after the lines were painted compared to the same 6-month period the year before (September 2006 – March 2007 and September 2005 – March 2006).

To see if it could make the road even safer, the city installed a series of overhead flashing beacons, yellow and black chevron alignment signs, and warning signs posting the reduced advisory speed limit. Again, accidents fell – 47 percent over a 6-month period (March 2007 – August 2007 and March 2006 – August 2006). Keep in mind that the post-six-month period effect included both the signs and the lines.

The more treatments the better is one conclusion to be drawn here, but the 36 percent reduction achieved with just the paint, without the added expense of the flashing signs, etc., is striking.

This entry was posted on Monday, January 11th, 2010 at 6:50 am and is filed under Traffic 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.