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The Safety Edge . What is it? How does it work? What are the benefits?. Ken Kochevar FHWA Division Office Safety and Design Team Leader Ph: (916) 498-5853. Mehdi Parvini Sr. Pavement Engineer Office of Pavement Engineering & Specification Development
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The Safety Edge What is it? How does it work? What are the benefits? Ken Kochevar FHWA Division Office Safety and Design Team Leader Ph: (916) 498-5853 Mehdi Parvini Sr. Pavement Engineer Office of Pavement Engineering & Specification Development Caltrans Pavement Management Program Ph:(916) 227-5848 Ken Kochevar Safety and Design Team Leader National Programs FHWA Division Office Ph: (916) 498-5853
122 530 68 162 228 98 447 399 383 223 635 136 1251 148 970 66 1387 382 268 215 1133 646 782 250 344 1071 3525 366 489 114 857 385 905 797 563 1421 1074 DC DC=34 663 971 933 577 373 1472 990 776 3084 869 67 2928 124 36,700 Fatal Crashes per Year 2006-2008 Average – Source: FARS Average 40,409 Annual Fatalities
2008 Fatal Crashes (Based on FARS) 34,017 U.S. Fatal Crashes 17,818 U.S. Roadway Departures
59 people will die in a roadway departure crash in the United States today. 1 Fatality Every 24 minutes
13,242 Roadway Departure Fatalities on Two Lane UndividedSource: 2008 FARS Data Focused Solution: • Low cost • Two Lane roadways • Roadway Departure
Vehicle Re-entry Are Drop-offs a Problem?
Head-on • Roll Over • Opposite Side • Roadside Hazard
Clip of TTI drop off road test: http://fhwa.na3.acrobat.com/safetyedgedrop
Location of Drop-offs 1.Horizontal Curves 2.Near Mailboxes 3.Turnouts 4.Shaded Areas 5.Eroded Areas (Drainage) 6. Asphalt Pavement Overlay
Shaded Areas Sunlight = Vegetation
Asphalt Overlay 2” Asphalt Overlay + Existing 5” Drop-off = Extreme Unsafe Condition
The Hardware GDOT Version IV GDOT Version V
The Hardware Advant-Edge TM Trans Tech Shoulder Wedge Maker TM www.transtechsys.com www.advantedgepaving.com
Key Features Self Adjusting Spring ½” Radius Leading Edge 450 Compound Angle 300 Forming Edge
Clip of safety shoe being installed http://fhwa.na3.acrobat.com/seshoeinstall/
Line Depicts extension of Pavement Surface 30o - 35o Line depicts a plane parallel to Pavement Surface from the toe of the wedge surface
Construction • Clip Shoulders • Construct Overlay • Pull Shoulders Flush • No Effect on Production • Minimal Monitoring • 12.5 mm or 9.5 mm SP
Clip of paving with Safety Edge http://fhwa.na3.acrobat.com/seshoe/ Clip of paving without Safety Edge http://fhwa.na3.acrobat.com/sewoshoe/
Existing pavement edge Breakpoint on wedge Toe of wedge New graded shoulder
Breakpoint on wedge Toe of wedge Location of the existing pavement edge under overlay
Increased Edge Compaction ? With Safety Edge Without Safety Edge
Safety Edge No Safety Edge Condition After One Year In-Service Six Edge Compaction
Benefits of A Safe Edge • Temporary safety benefit during construction • Permanent Solution for future drop-off re-emergence • Reduce tort liability – Providing “Due Care” • Minimal hardware, labor, or material costs • Increased Pavement Edge durability
Safety Edge Implementation Standard Practice Projects Built State Evaluating Safety Edge States without activity Pool-fund States
Every Day Counts (EDC) Initiative • Initiated Spring of 2010 • EDC designed to identify and deploy innovation • Shortening Project Delivery • Enhancing Safety of our Roadways • Improving Environmental Sustainability • Safety Edge: 1 of 5 solutions • Goal: 40 states adopting Safety Edge by Dec. 2011
What can FHWA offer ? • 10-12 demo projects for 2010-2011: • Free loaner equipment • Technical assistance • Project documentation • Promotional Material • Specifications • Tech Drawings
Safety Edge Detail Original Width Variable Width for Safety Edge HMA/PCC Lane or Shoulder Aggregate Shoulder or Shoulder Backing Existing Lane or Shoulder Existing Shoulder or Shoulder Backing Safety Edge Angle
Factors that Impact the Effectiveness of the Safety Edge • Edge drop off height • Type of highway (undivided, number of lanes) • Shoulder width • Design speed • Curve • Rumble strip • Ditch/guard rail at the edge
Criteria for Using Safety Edge For demonstration projects: • All new and rehabilitation pavement projects that create pavement edge drop off more that 0.15 ft For subsequent projects: • Further crash data analysis is underway to come up with most efficient locations for the safety edge
Safety Edge Specification The contractor shall attach a device to the screed of the paver that confines the material at the end gate and extrudes the asphalt material in such a way that results in a compacted wedge shape pavement edge of approximately 30 degrees (not steeper than 35 degrees). The device shall maintain contact to the road shoulder surface. It shall also allow for automatic transition to cross roads, driveways and obstructions. The device shall constrain the asphalt head reducing the area by 10 to 15% increasing the density of the extruded profile. Conventional single plate strike off are not allowed. The contractor may use the TransTech Shoulder Wedge Maker or the Advant-Edge or a similar device that produces the same wedge consolidation results. If the contractor uses a similar device, he must provide proof that his device has been used on previous projects with acceptable results or the contractor shall construct a test section prior to the beginning of work and demonstrate wedge compaction to the satisfaction of the engineer. Short sections of handwork will be allowed when necessary for transitions and turnouts or otherwise authorized by the engineer. This work will be included in the pay item Hot Mix Asphalt.
Safety Edge Cost • Equipment – about $3,500 (one time expense) • Material – 1% to 2.5% of a typical overlay cost
More Information • http://safety.fhwa.dot.gov/roadway_dept/pavement/safedge/ • www.pooledfund.org • TPF-5(097) Evaluation of the Safety Edge • Specifications and Drawings • Safety Impacts of Pavement Edge Drop-offs: www.aaafoundation.org, September 2006
Challenge What will you do this year to make our highways safer ? • Low Cost • Focused • Proven