University of Kansas
About the research
The reflectorized sleeves are designed to wrap around a standard reflectorized drum, providing an alternate color scheme (orange, white, and green stripes). The use in this evaluation was to apply the sleeves to drums on an exit within an Interstate work zone where the exit is delineated by drums. The intent of the application was to provide more positive guidance for the driver by more clearly defining which two drums on the mainline mark the mouth of the exit ramp. Three configurations of sleeves were compared to baseline data collected without the sleeves. The measure of effectiveness was the speed reductions occurring within the exiting stream before the vehicles leave the mainline. Speeds were monitored just upstream of the exit and immediately downstream of the exit on both the ramp and on the mainline. Custom software was developed to identify exiting vehicles in the downstream data and extract their speeds from the upstream data. The idea is that drivers often slow while still on the mainline, partly because the ramp is more difficult to identify when delineated by drums than under normal conditions. If the drum sleeves improve the delineation of the ramp, drivers will be less apt to slow down before exiting, thus providing for smoother flow on the mainline. The sleeves were easily installed, did not come off the drums even under severe duress (i.e., being blown over by a store and being run over by a truck), and they proved to be quite durable. Several drums were hit by vehicles during the test and only one sleeve suffered major damage. The speed data showed no statistically significant difference between the baseline and any of the three tested configurations. In retrospect, the site was less than ideal for this test because the location was nearly ideal for safety. The road was flat and straight, and only a short portion of the mainline was delineated by drums. Consequently, the ramp was very well delineated without the sleeves. While the may have some benefit, they were not needed at this site. Additionally, their effect would likely be most pronounced at night when delineation is most critical, but the traffic volumes on the exit at night were too low to support statistical analysis.