1 / 12

Consideration of Roadside Features in the Highway Safety Manual

Consideration of Roadside Features in the Highway Safety Manual. Project PI: Malcolm H. Ray, P.E., PhD RoadSafe LLC mac@roadsafellc.com 207-514-5474 Presented by Team Member: Karen K. Dixon, P.E., PhD Emails: karen.dixon@oregonstate.edu OR k-dixon@tamu.edu . N C H R P 17-54.

mina
Download Presentation

Consideration of Roadside Features in the Highway Safety Manual

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Consideration of Roadside Features in the Highway Safety Manual Project PI: Malcolm H. Ray, P.E., PhD RoadSafe LLC mac@roadsafellc.com 207-514-5474 Presented by Team Member: Karen K. Dixon, P.E., PhD Emails: karen.dixon@oregonstate.edu OR k-dixon@tamu.edu N C H R P 17-54

  2. Objective of NCHRP 17-54 • Develop quantitative measures that can be incorporated into the HSM to evaluate the effects of roadside designs and features on the frequency and severity of lane departure crashes.

  3. 17-54 Phase I completed • Literature review • Compared RSAPv3 and the HSM • Encroachment method • Crash-based method • Recommendations for use of both methods • Analyzed sample scenarios • Very different results • Different base conditions • Different units (i.e., single vehicle crashes vs. ROR crashes) • Identified potential data sources and existing CMFs • Interim Report submitted June 6, 2012.

  4. Schedule • 17-54 Interim Report meeting: May 2012 • Modifications to RSAPv3: June 2012 • Quantitative Measures for HSM: Early 2013 • Final Report: Summer 2013

  5. Rural Two-Lane Two-Way Segments Default distribution incudes SVROR crashes (52%) and Overturned (2.5%). No separate SPF for SVRORs (Calculated as a proportion of the total). SVROR is a major crash type but SVROR is only a part of ROR. HSM SPF functional form increases with ADT (generally linear shape). Roadside Hazard Rating is the main measure of roadside condition.

  6. Rural Multi-Lane Highways Segments Default distribution includes SV crashes (77%) . SV are a major crash type for this highway type but ROR crashes are not exactly the same as SV crashes. No separate SPF for SV crashes (Calculated as a proportion of the total). HSM SPF functional form increases with ADT (generally linear shape).

  7. Urban and Suburban Arterial Segments A separate SPF for SV crashes by road type. SV overlaps with ROR but is not the same. Different coefficients for the SPF based on road type. Separate SPFs for vehicle-pedestrian and vehicle-bicyclist. Non-linear relationship between ADT and crash frequency.

  8. Freeway Segments Research just completed Not part of the NCHRP 17-54 Contract

  9. Conclusions • The current SPFs for each road types handle ROR crashes differently. All lump ROR crashes in with something else (i.e., SV or SVROR) • Per Panel Instructions, Project 17-54 will develop new RORSPFs and CMFs for each road type • Phase II – Rural 2-lane and multilane (current effort) • Phase III – Urban and Suburban

  10. Expectations for Use • RSAPv3 will continue to be the go-to tool for the analysis of detailed roadside design scenarios and the development of roadside policy. • The new HSM ROR Predictive method and companion CMFs will be the go-to tool for preliminary design and scoping of roadside issues.

  11. Questions to Consider How should we integrate these new SPFs into an updated HSM? - A new section in each chapter for ROR? - A new chapter on ROR? - How do we handle inconsistencies between the new ROR SPFs and the existing ones? What about double counting?

  12. While some things have changed… Some remain the same!

More Related