PART IV: Summary of Comments - SCOR/RAC

PART IV: Summary of Comments17-May-10Reviewer Comments Distribution of RatingsItem #26:G-08Strategies for Improving the Safety of Horizontal Curves(17)(46)NR 0 1 2 3 4 5SCOR 1 2 1 7 6RAC 1 2 8 14 14 10Standing Committee on Research■ This is an interesting project, but care should be taken that it is compatible with procedures in the new Highway SafetyManual. States will be investing considerable resources in gearing up for HSM adoption, and I worry that this projectmay produce a competing methodology for examining horizontal curves. Interesting topic. Attempt to overcometraditional statistical approaches. Challenge would be validation of the "structure" models.■ Seems an impossible task on any sort of national level and the literature review is sparse. Though examining curvecrashes make sense. Efforts like the ones underway in Iowa and other states seem to be going well. Suggest rewrite theproposal to examine states' efforts and develop a next-phase project.■ It is not clear whether a macroscopic model will be successful in predicting the accidents, but it seems worthwhile to try.■ Needed research to help understand contributing factors in crashes at a site.■ Good problem and can be analytically robust, but not sure how much of applications to the real world will actuallyhappen.■ [Rating: 4] The topic is very important to research and gain better understanding, however there are so many variables toinclude and so much research going on already in this area that the problem statement may be too broad to effectivelymanage as written.Research Advisory Committee■ NC has made several (NCDOT funded) recent Safety Research efforts to attempt to address and improve identificationand treatment of horizontal curves. NC is also looking at additional systemic approaches to address lane departurecrashes and horizontal curves are a key component of that effort. Unfortunately much of the research on horizontalcurves has been filtered to simple curves whereas in reality there are many complex curves with variable/non symmetricradii (that were never engineered to begin with), vertical/superelevation and grade issues, and increasingly more locationswith acess points (driveways and street intersections within the influence area if not inside the curve itself).■ This proposal does a good job of outlining the issue, and makes a reasonably strong case for a more holistic approach tohorizontal curve safety analysis. The probability of success is unclear as the availability of some data elements may be alimiting issue. IHSDM may have explored some of this.■ Once various strategies are identified and tested, the implementation should at a minimum significantly improve thecurrent process. Highway crash data supports addressing the horizontal curve problem.■ There seems to be a lot of other research out there already on rumble strips, longitudinal barrier, etc.Other■ [Rating: 4]Item #27:G-18Safety Evaluation of the 13 Controlling Criteria forDesign(17)(46)NR 0 1 2 3 4 5SCOR 2 6 6 3RAC 1 7 16 14 11Standing Committee on Research■ Good idea but all features such as turn lanes are not included. The 13 critieria should be revisited.We are likely to gaina lot more knowledge as we implement the HSM. It can wait until enough progress of implementing the HSM is made.■ It would be prudent to evaluate the assumptions that were used in establishing the original controlling criteria andIV-15