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FHWA: Revision of Thirteen Controlling Criteria for Design; Notice for Request and Comment. Comments Due: December 7, 2015 Jeremy Fletcher, P.E., P.S.M.

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Presentation on theme: "FHWA: Revision of Thirteen Controlling Criteria for Design; Notice for Request and Comment. Comments Due: December 7, 2015 Jeremy Fletcher, P.E., P.S.M."— Presentation transcript:

1 FHWA: Revision of Thirteen Controlling Criteria for Design; Notice for Request and Comment. Comments Due: December 7, 2015 Jeremy Fletcher, P.E., P.S.M. (850) 414-4320

2 1998 DDE/DCPMEs

3 USDOT/FHWA Press Release

4  “Opens the way for more design choices, more bicyclist-pedestrian options nationwide.”  “Encourage the design of lower- speed roads to be more in-line with community and environmental needs.”  “…give states and communities the opportunity to be more innovative in designing their local projects” Secretary Foxx. USDOT/FHWA Press Release

5  Industry move towards Performance Based Practical Design Approach.  Rulemaking underway to adopt 2011 AASHTO Greenbook.  Updated Bike/Ped Guidance. Controlling Element Changes

6 CurrentRecommended Design Speed Lane Width Shoulder Width Bridge Width Structural Capacity Design Loading Structural Capacity Horizontal AlignmentHorizontal Curve Radius Vertical Alignment GradeMaximum Grade Stopping Sight Distance Cross Slope Superelevation Vertical Clearance Horizontal Clearance 10 HS Controlling Criteria 13 10 HS Controlling Criteria

7 CurrentRecommended Design Speed Lane Width Shoulder Width Bridge Width Structural Capacity Design Loading Structural Capacity Horizontal Alignment Vertical Alignment Grade Stopping Sight Distance Cross Slope Superelevation Vertical Clearance Horizontal Clearance 2 LS Controlling Criteria 13 2 LS Controlling Criteria

8  Since 1985 using same Controlling Elements  NCHRP Project 17-53 Quantified impacts on Capacity from the Highway Capacity Manual Quantified impacts on Safety from the Highway Safety Manual Objectives and Scope

9  Urban and rural roadway types Intersection design, access management and roadside design were not reviewed.  Includes: new construction and reconstruction projects Does not include RRR projects  New CMFs included  Recommendation to retain or not retain some controlling criteria 783 Objectives and Scope

10 Priorities Based on Safety Priority Rank Roadway Type Rural 2-lane highwaysRural multilane highwaysRural freeways TRAFFIC SAFETY 1Shoulder width 2Lane width 3GradeSSD w/hidden curve, intersection, or driveway Horizontal curve radius 4 SuperelevationSSD w/hidden curve or ramp junction 5SuperelevationGradeSuperelevation 6SSD w/hidden curve, intersection, or driveway Horizontal curve radiusGrade 7Bridge Width 8Cross Slope 9Sag vertical curve length 10SSD w/no hidden features 11Lateral offset

11 Priorities Based on Operations Priority Rank Roadway Type Rural 2-lane highways Rural multilane highways Rural freeways TRAFFIC OPERATIONS 1Shoulder widthLane width 2 Shoulder width 3Horizontal curve radius 4Grade 5Bridge width 6Superelevation 7SSD w/hidden curve, intersection, or driveway SSD w/hidden curve or ramp junction 8SSD w/no hidden features 9Sag vertical curve length 10Cross slope 11Lateral offset

12  All facilities: Retain as a controlling criterion for all facilities. AASHTO Ranges provide a lot of flexibility. More appropriate to analyze specific elements rather than D.S. Design Speed

13  Low Speed: Do not retain  High Speed: Retain Largest effect on crashes and operation of all 13 elements HSM CMFs available for most facilities. 2014 HSM Supplement ○ Freeways and Ramps (New CMFs Available) Shoulder Width

14  Low Speed: Do not retain.  High Speed: Retain Prepare Design Exceptions for lane widths less than 11’ Arterials ○ (CMF=1.05 for 11’) 12’ on Interstates. Known safety and operational effects in the Highway Safety Manual and Highway Capacity Manual. 2014 HSM Freeways and Ramps Lane Width

15  All Facilities: Remove as a controlling criteria as shoulder width covers this. No Variations or Exceptions for Low- Speed Bridges. Before/After Study Finding: “No evidence of increased crash frequencies or severities for bridges narrower than the approach roadway.” Bridge Width

16  Renamed to “Horizontal Curve Radius”  Low Speed: Do not retain  High Speed: Retain due to documented relationship to crash frequency. Horizontal Curve Radius

17  All Facilities: Removed as a controlling element. Crest curves are addressed through Stopping Sight Distance Evaluations. Grade covered Separately Sag Vertical Curves not an issue, day or night. Vertical Alignment

18 Grade  Applies to only maximum grades. Minimum grades do not alone ensure sufficient drainage.  Low Speed  Do Not Retain  High Speed  Retain as a controlling criterion.  New CMF for Grades Developed in Report 783 research. (CMF=1.0+0.016G)

19  Current Criteria: Evaluate all crest and horizontal curves against minimum AASHTO SSD.  Low Speed: Do not retain  High Speed: Retain due to long SSD needed to enable a vehicle to stop at D.S. Documented crash characteristics. Stopping Sight Distance

20  Lower in priority with regard to safety in priority rankings.  Low Speed: Do not retain  High Speed: Retain as a controlling criterion due to negative consequences of poor drainage.  NCHRP 03-105: Shoulder Breakover Research Planned Cross Slope

21  Criteria: Evaluate on all roads to meet AASHTO 4% and 12% Tables.  Low Speed: Remove as a controlling criterion for Design Speeds 45 mph and Less.  High Speed: Retain as a controlling criterion due to crash relationships for two-lane and multi-lane facilities. Superelevation

22  All Facilities: Remove as Controlling Element For Flush Shoulder facilities, shoulder width ensures offset width. For Curb Facilities, striking roadside objects and car opening are not as critical as other controlling elements.  Clear Zone has impacts on safety, but not reviewed in the Report 783 study. Horizontal Clearance/Lateral Offset

23  Low Speed: Not retained. (What about interchanges?)  High Speed: Retained, due to severe impacts on operations after bridge hits. (Road Closures) Vertical Clearance

24  All Facilities: Retain Related to design of the structure, not Load Rating. Impacts freight, emergency, military, and traveling public mobility.  Not addressed in 783 research. Design Loading Structural Capacity

25  Design Criteria not met  Existing Roadway conditions  Alternatives  Analysis of standards vs. proposed criteria  Quantitative Analysis  Impacts to r/w, environment, community, all users,  Project costs  Mitigation  Compatibility with adjacent sections  Future projects which will fix condition. FHWA Design Documentation Expectations

26  Comments Due by December 7.  The FHWA will respond to comments received on the guidance in the second Federal Register notice, to be published after the close of the comment period.  The Second notice will include the final guidance memorandum and reflect any changes implemented! Next Steps


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