The Safety Edge
What is it?
How does it work?
What are the benefits?
Mehdi Parvini
Ken
KenKochevar
Kochevar
SafetyDivision
and Design
Team Leader Sr. Pavement Engineer
FHWA
Office
National
Safety
andPrograms
Design Team LeaderOffice of Pavement Engineering
& Specification Development
FHWA Division Office
Ph: (916) 498-5853
Ph: (916) 498-5853
Caltrans Pavement Management
Program
Ph:(916) 227-5848
MAKING PAVEMENTS SAFER and MORE DURABLE
2
36,700 Fatal Crashes per Year
2006-2008 Average – Source: FARS
122
530
228
68
98
162
447
399
383
223
635
136
148
970
3525
1071 782
250
489
385
905
1133
646
366
663
373
1421
114
563
DC
DC=34
933
577
776
3084
857
797
1074
971
66
268
1387
382
215
344
1251
990
1472
869
67
2928
124
Average 40,409 Annual Fatalities
3
2008 Fatal Crashes (Based on FARS)
34,017
U.S. Fatal
Crashes
17,818 U.S.
Roadway
Departures
4
59 people will die in a roadway departure
crash in the United States today.
1 Fatality Every 24 minutes
5
13,242 Roadway Departure Fatalities
on Two Lane Undivided
Source: 2008 FARS Data
Focused Solution:



Low cost
Two Lane roadways
Roadway Departure
6
Are Drop-offs a Problem?
Vehicle Re-entry
7

Head-on

Roll Over

Opposite
Side

Roadside
Hazard
8
Was the drop-off
the cause?
9
Clip of TTI drop off road test:
http://fhwa.na3.acrobat.com/safetyedgedrop
10
11
12
Location of Drop-offs
1.
Horizontal Curves
2.
Near Mailboxes
3.
Turnouts
4.
Shaded Areas
5.
Eroded Areas (Drainage)
6.
Asphalt Pavement Overlay
13
Horizontal Curves
14
Mail Boxes
15
Shaded Areas
Sunlight = Vegetation
16
Asphalt Overlay
17
The Safety Edge:
A Practical Solution
18
The Hardware
GDOT Version IV
GDOT Version V
19
End Gate Springs
20
The Hardware
Trans Tech Shoulder Wedge Maker TM
www.transtechsys.com
Advant-Edge TM
www.advantedgepaving.com
21
Key Features
Self Adjusting Spring
300 Forming Edge
½” Radius Leading Edge
450 Compound Angle
22
Clip of safety shoe being installed
http://fhwa.na3.acrobat.com/seshoeinstall/
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Line Depicts
extension of
Pavement Surface
o
o
30 - 35
Line depicts a plane parallel to
Pavement Surface from the toe of the
wedge surface
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Construction
 Clip Shoulders
 Construct Overlay
 Pull Shoulders Flush
 No Effect on Production
 Minimal Monitoring
 12.5 mm or 9.5 mm SP
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Clip of paving without Safety Edge
http://fhwa.na3.acrobat.com/sewoshoe/
Clip of paving with Safety Edge
http://fhwa.na3.acrobat.com/seshoe/
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Breakpoint on wedge
Existing pavement
edge
Toe of wedge
New graded shoulder
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Breakpoint on wedge
Toe of wedge
Location of the
existing pavement
edge under overlay
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Iowa PCCP Safety Edge
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Increased Edge Compaction ?
With Safety Edge
Without Safety Edge
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Edge Compaction
Safety Edge
No Safety Edge
Six
Condition After One Year In-Service
31
Durability
32
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
33
Safety Edge Implementation
Standard Practice
Projects Built
State Evaluating Safety Edge
States without activity
Pool-fund States
34
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
35
What can FHWA offer ?
 10-12 demo projects for 2010-2011:






Free loaner equipment
Technical assistance
Project documentation
Promotional Material
Specifications
Tech Drawings
36
Safety Edge Detail
Original Width
Variable Width for Safety Edge
HMA/PCC Lane or Shoulder
Existing Lane or Shoulder
Safety Edge Angle
  30

Aggregate Shoulder or Shoulder Backing
Existing Shoulder or Shoulder Backing
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 AdvantEdge 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/paveme
nt/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
42
Challenge
What will you do this year to make our
highways safer ?
 Low Cost
 Focused
 Proven
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We need your help!
Questions??