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Suggested Citation:"Appendix B. Comments on Survey Responses." National Academies of Sciences, Engineering, and Medicine. 2021. Application of Crash Modification Factors for Access Management, Volume 2: Research Overview. Washington, DC: The National Academies Press. doi: 10.17226/26162.
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Suggested Citation:"Appendix B. Comments on Survey Responses." National Academies of Sciences, Engineering, and Medicine. 2021. Application of Crash Modification Factors for Access Management, Volume 2: Research Overview. Washington, DC: The National Academies Press. doi: 10.17226/26162.
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Suggested Citation:"Appendix B. Comments on Survey Responses." National Academies of Sciences, Engineering, and Medicine. 2021. Application of Crash Modification Factors for Access Management, Volume 2: Research Overview. Washington, DC: The National Academies Press. doi: 10.17226/26162.
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Suggested Citation:"Appendix B. Comments on Survey Responses." National Academies of Sciences, Engineering, and Medicine. 2021. Application of Crash Modification Factors for Access Management, Volume 2: Research Overview. Washington, DC: The National Academies Press. doi: 10.17226/26162.
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Page 218

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B-1 A P P E N D I X B Comments on Survey Responses Some questions invited comments from responses in addition to the provided response, or as a follow up question. These comments are summarized below in through Table B-1 through Table B-5. Table B-1. Question 1- Do you quantify the safety effects of access management strategies to support related decisions? Comment We quantify the effects of access management by using applicable CMF’s from the clearing house (national study’s) - we do not have any specific to Oregon. We use CMFs for various treatments to evaluate safety projects and general TIP projects. Depending on the project we may use different methods. One common one we use is just reduction in conflict points. We use quantitative safety to consider different aspects of access control. This is mostly in the design / project scoping phase. But we want to. No but access management aspects are included in the Development Coordination Manual and Road Design Manual. This has quantified only for one particular project, inextricably combined with other factors. Only for projects that request Safety Program funding (state or federal). A naive before/after study was performed on a raised median installation combined with capacity improvements. Results showed a reduction in crashes and a substantial reduction in the KA crash rate. We attempt, where possible, to use criteria from the Safety Manual, our Design Manual, and established access management elements to determine the access management criteria for projects and applications for access to our highways. Some Corridor Management Plans include the safety effects of proposed strategies, most do not. The safety effects of individual improvements are not quantified outside of Corridor Plans at this time. Only because we have not advanced to this level of analysis. WSDOT has done analysis related to benefits on a few projects We look at crash data along corridors/ roadway segments to determine if strategies like adding a median would be appropriate (especially for safety driven projects). We also look at statewide historical crash data for determining best practices for typical section choices. By use of Crash Modification Factors and Benefit Cost Analysis.

B-2 Where information is available for a given strategy, this information would be used to quantify the anticipated benefit and might be used to help promote the strategy - both internally and with the community. WisDOT completes safety effectiveness evaluations for all of our HSIP projects including those that involve access management treatments. WisDOT has also evaluated a few corridor-wide access management projects to help support future access management decisions. WisDOT currently uses CMFs to support access management improvements in HSIP and sometimes in other traditional improvement projects. With Reduced conflict intersections, we have conducted before and after studies to determine the reduction in overall, injury, and fatal crashes. These numbers help support our decisions. In the past we have used an FHWA chart which shows the reduction in crashes based on number of access points along a corridor. This chart is now quite old, so an updated analysis would be helpful. Table B-2. Question 2- Do you have a policy or procedure for assessing the safety effects of access management strategies? Comment Access management strategies are defined/prescribed in Oregon Administrative rules (OAR 734-51) which include spacing, sight distance, channelization, and safety and operations considerations. For private approach permitting, safety is assessed by reviewing crash rates, weaving/queuing conditions, top 5% (Safety Priority Index System) SPIS location etc. For those locations in the top 5% SPIS list, they are reviewed closely to look more fully at measures that will help to improve safety. Most requests for safety monies that are associated with access management are projects that are dividing the highway either with a raised median or median barrier making the existing accesses subject to right-in- right-out traffic maneuvers. As such, a cost benefit assessment is conducted based on the expected crashes reduced by dividing the highway. This is done by either directly applying a CMF for the mitigation (preliminary), or more often with an expected crash analysis comparison between the two configurations as outlined in Part C of the Highway Safety Manual (1st Edition) (2010). Naive before/after studies. We have started to use the Highway Safety Manual (1st Edition) to try to quantify the potential reductions that access management could have within a project or city. Recognizing the importance of access management strategies, our design guidelines have basic restrictions on the number of access points per mile for rural and suburban locations. We have general policy, but not specifically to the safety effects of access management. We probably do, related to the typical section choices (see previous response), but I don't have the link. Occasionally a researcher will gather data for some projects, but nothing that is routine. Traffic safety does a good job detailing the benefits of RCI's. I am not aware of any other procedure.

B-3 Table B-3. Question 3- Do you track safety-related performance measures after implementing access management strategies? Comment No, we typically do not track safety-related performance measures after implementation; this isn’t part of our process. We mainly rely on determining the effectiveness of the strategies as identified in ODOT’s CRF list (http://www.oregon.gov/ODOT/Engineering/Pages/ARTS.aspx) Sometimes we conduct before-after analyses of batches of similar projects. We have done some studies but do not track anything official. Only for projects that have been funded with HSIP federal funds as required by the yearly report. Currently we provide a 3 year before and after analysis for the locations. See above. Although not for all applications, we have reviewed access management installations after the fact to determine effectiveness of the installation. We typically wait three years to make that determination. We may look at simple before and after for specific projects. Only occasionally Not as often as we should... Only if we do an after study. We track all safety funded projects and report to the legislature. On a limited basis we have quantified the safety impacts related to access management efforts. Our agency has conducted several Safety projects which have deployed access management features. These have primarily included J-turn (or RCUT) projects and the conversion of 5-lane undivided highways with a two-way continuous center left turn lane into divided highways with dedicated left turn lanes. Crash data is monitored on these HSIP projects. We have gone back and done some evaluations of access management projects but we don't track these projects statewide. Personally, I do not. Table B-4. Question 4- What is your priority need to estimate the safety effects of access management strategies? (Please select your higher priority) Comment Would also be helpful, with public outreach, to have some background information stating how the effects of combination strategies can improve safety (for example, PowerPoint slides, handouts etc.) Hard to pick one--both are site specific and are needed Both are desirable but isolated improvements are more likely to be achievable. These projects are only done if the local agencies support the enhancement. We attempt to use both of these elements, where applicable, equally. At this point, the majority of our focus is on individual strategies, making it a higher priority, but combination strategies would be helpful as well.

B-4 Difficult selection - both might be necessary in any given situation. I could see where it might be difficult to attribute a percentage of the overall safety benefit to one strategy where multiple strategies are deployed as part of the same project. With Access Management Plans we are identifying several safety improvements along/adjacent to a corridor. I think that showing the benefit of several improvements in concert will be more significant than showing the benefit of individual improvements. Table B-5. Question 7- Are there other access management strategies or combination(s) of strategies that should be prioritized in this project? Comment Median installation, reduction of driveway density, and addressing open access within the influence area of an intersection. Avoiding the addition of a fourth leg at a three-legged intersection. Prohibiting movements at a signalized intersection so as to avoid additional phases. I don't know any Not that I can think of. How do access management techniques impact pedestrian and bicyclists? Both from a crash perspective, and from how people feel using these facilities? Should the traffic volume of an access point affect the minimum spacing? For example, it seems that a high-volume access should be spaced farther from another high-volume access than from a low- volume access or between two low-volume accesses. The effect of access management on non-motorized. E.g., increased exposure Partnering with local agencies where they might adopt and enforce the State's Access Management Guidance/Policies in order to provide effective access management at interchanges & intersections that involve state highways and local roads. It would be good to quantify the general before and after benefits of displaced left turns as well as continuous flow T-intersections. I often wonder about the safety associated with the spacing of non-traditional intersections. E.g., since RCI's elongate an intersection, would the spacing needs be greater, or would they be less since the intersection operates more effectively. How would that impact safety? Aside from safety for cars, would the various strategies have positive or negative impacts on bike/ped traffic? Also, would bypass lanes generally show an increase or decrease in safety? For trucks needing to turn left from the minor leg to the major leg, do inside merging lanes work? There is definitely disagreement pertaining to this.

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Application of Crash Modification Factors for Access Management, Volume 2: Research Overview Get This Book
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The 1st Edition, in 2010, of the AASHTO Highway Safety Manual revolutionized the transportation engineering practice by providing crash modification factors and functions, along with methods that use safety performance functions for estimating the number of crashes within a corridor, subsequent to implementing safety countermeasures.

The TRB National Cooperative Highway Research Program's pre-publication draft ofNCHRP Research Report 974: Application of Crash Modification Factors for Access Management, Volume 2: Research Overview documents the research process related to access management features.

Supplementary to the report is the pre-publication draft of NCHRP Research Report 974: Application of Crash Modification Factors for Access Management, Volume 1: Practitioner’s Guide and a summary presentation for the two volumes.

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