Supporting Material to NCHRP Report 674 (2011) / Chapter Skim
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From page 16... ...
APPENDIX C: Team Treatment Survey This Appendix contains details about the team-internal treatment survey used to reduce the long list of treatments to a recommended short list.
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Appendix C: Team Treatment Survey Due to the limited financial resources and time constraints imposed by the project, the research team conducted an internal survey aimed at identifying candidate treatments to be installed at the sites described later in the report. A scale of 1 to 5 was used with 5 indicating the treatment as being very effective.
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Appendix C: Team Treatment Survey Table 4: Team Estimates of Treatment Effectiveness: Median Ratings by Research Team VEHICLES VEHICLES P(YD)
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Appendix C: Team Treatment Survey Table 5: Team Estimates of Treatment Effectiveness: AVERAGE Ratings by Research Team VEHICLES VEHICLES P(YD)
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Appendix C: Team Treatment Survey COMMENTS Base Case, Unassisted X-ing, Static Signs REVIEWER #1 REVIEWER #2 REVIEWER #3 - There will be great differences in yield and gap detection depending on the geometry of the baseline roundabout or channelized turn lane. I'm assuming a 2land RAB with no particular traffic calming other than what is expected in good RAB design.
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Appendix C: Team Treatment Survey In-roadway warning sign REVIEWER #1 - Not effective for blind peds unless paired with a yield detection system of some sort. I think an active intervention will be more effective than passive.
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Appendix C: Team Treatment Survey REVIEWER #8 - Ped Delay performance measures seem to be directly related to driver yielding behavior - more yielding, less delay (assuming yield detection) REVIEWER #9 - Potential maintenance challenges 'Active When Present' REVIEWER #1 - Not effective for blind peds unless paired with a yield detection system of some sort.
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Appendix C: Team Treatment Survey REVIEWER #6 - I don't see much benefit here - and it certainly would increased the likelihood of missed yields on the part of blind folk REVIEWER #7 - Would negatively affect blind pedestrians' ability to detect yielding vehicles, because cars would be further away; don't know that it would affect drivers' probability of yielding at all. Where do you put an advanced yield line for the exit crossings?
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Appendix C: Team Treatment Survey REVIEWER #9 - Geometric delay is less likely to be perceived by drivers than control (e.g., signal) delay.
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Appendix C: Team Treatment Survey decreased delay, but may not reduce risk decisions. Expected to have considerable benefit for wayfinding -- staying within crosswalk.
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Appendix C: Team Treatment Survey PEDESTRIAN INFORMATION TREATMENTS Surface Alterations / Rumble Str. REVIEWER #1 - If rumble strips are present primarily to give auditory info, there are problems with placement that are tough to overcome.
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Appendix C: Team Treatment Survey this over a signal. If you think about it, the system will only give you a 'crossable gap' indication, if there is no traffic - well if there isn't any traffic than you don't really have to worry about a signal causing vehicle delay!
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Appendix C: Team Treatment Survey REVIEWER #8 - This makes more sense than GD alone - but I am still hesitant of the effectiveness and reliability of the gap detect component of the system REVIEWER #9 DISTAL/MIDBLOCK CROSSING Set back XX feet BOTH CROSS. REVIEWER #1 - This logically seems to provide some useful effect but I don't think the effect is that great.
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Appendix C: Team Treatment Survey REVIEWER #4 - Not expected to result in much, if any, improvement in gap/yield detection. I think TTI data may be useful for modeling the effect of different speeds and widths on yielding.
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Appendix C: Team Treatment Survey REVIEWER #8 - The added benefits are obviously only at the exit leg to a roundabout - but they should be quite significant here. REVIEWER #9 - Depends on space to accomplish this.
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Appendix C: Team Treatment Survey REVIEWER #5 - Detection of gaps and yields are n/a if signal is present (or a 5.0 in terms of elimination of requirement)
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Appendix C: Team Treatment Survey HAWK Signal at Splitter Island - One Stage REVIEWER #1 - Ratings assume presence of an APS. With that, will provide excellent crossing info, testing done in Raleigh seemed to support this, but placement needs to be investigated.
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Appendix C: Team Treatment Survey REVIEWER #3 - Ratings assume presence of an APS. Expected to result in good yield/gap detection as well as yield rate.
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Appendix C: Team Treatment Survey REVIEWER #5 - Detection of gaps and yields are n/a if signal is present (or a 5.0 in terms of elimination of requirement)
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Appendix C: Team Treatment Survey REVIEWER #7 REVIEWER #8 REVIEWER #9 - Not practical for CTLs at signalized intersections due to queues at signal unless midblock crossing is 250+ ft away - doesn't qualify as treatment of intersection. Distal Ped.
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From page 36... ...
Appendix C: Team Treatment Survey REVIEWER #8 - more difficult at CTL - would have to go across entire intersection to make sense REVIEWER #9 - Eliminates interaction and therefore delay between vehicles and peds. Completely impractical and undesirable in 99.99% of all cases, plus unnecessary to test - recommend dropping.
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