Transcript McDonnell Roadside Design Guide and MASH

Keith A. Cota, New Hampshire Department of Transportation
Status of the
Roadside Design Guide
Update
AASHTO Subcommittee on Design
July 19-23 2009
Indianapolis, Indiana
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Roadside Design Guide
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Presentation Overview
• Update Objectives
• Research Studies
• Schedule for Completion
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Update Objectives
 Statistics Updated
 Incorporated Latest Research
 Resolved Conflicts related to Clear Zone
(NCHRP 20-7, Task 171) within
AASHTO Documents
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Clear zone
Clear recovery area
Horizontal clearance
Lateral offset
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Update Objectives
Minimum
Lateral Offset
vs.
Clear Zone
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Update Objectives
 Reduced listing of hardware by
referencing AASHTO-AGC-ARTBA
Task Force 13 Report, “A Guide To
Standardized Highway Barrier
Hardware”
 http://aashtotf13.org
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Update Objectives
 Referenced Acceptance Letters from
FHWA’s Office of Safety
http://safety.fhwa.dot.gov/roadway_dept/
road_hardware/index.htm
 Added Reference for Updated Crash
Test Criteria Under MASH and
FHWA/AASHTO Implementation Plan
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Update Objectives
 New chapter on Low Volume Roads,
including guidance on:
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Clear zone
Drainage placement
Slope and ditch cross-sections
Barriers (TL-2)
Sign supports
Utility pole placement
etc.
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Update Objectives
 Updated chapter for Urban Areas, including
guidance on:
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clear zone
lateral offset (4-6 ft)
landscaping (including median applications)
sidewalk placement
slope and ditch cross-sections
sign supports
utility poles placement
traffic signals
mailbox locations
etc.
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Urban Chapter Objectives
Urban rights-of-way are often extremely restricted,
limiting the applicability of clear-zone practice –
even in suburban-to-urban transitions.
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Urban Chapter
Landscape Buffer (Planting Strip) Configuration
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Update Objectives
• RSAP (Roadside Safety Analysis
Program)
– Update will maintain current RSAP
program
– Intent to supplement at time of completion
of NCHRP 22-27, “RSAP Update,”
currently under contract
– Anticipated completion – 2010 or sooner?
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Update Objectives
• Technical Assistance through
NCHRP 20-7, Task 240, “Update of
AASHTO Roadside Design Guide”
– Contract with King Mak
– Provide technical assistance, research
overview, and chapter consistency
review
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Research Studies
• NCHRP Project 22-17 – “Recommended Guidelines
for Curbs and Curb-Barrier Combinations”
• NCHRP 22-19 “Aesthetic Concrete Barrier and
Bridge Rail Designs”
• NCHRP 16-04 “Design Guidelines for Safe and
Aesthetic Roadside Treatments in Urban Areas”
• NCHRP 22-18 “Crashworthy Work Zone Traffic
Control Devices”
• NCHRP 20-7 (196) “Development of a Guide to
Crashworthy Bridge Rail Systems”
• NCHRP 16-04 “Median Intersection Design for Rural
High-Speed Divided Highways”
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Research Studies
• NCHRP 17-13 “Strategic Plan for Improving
Roadside Safety”
• NCHRP 20-7 (171) “Guidelines for the Selection of
Cable Barrier Systems”
• FHWA Memoranda on:
– “Guidelines for the Selection of W-Beam Barrier Terminal”
– “High Tension Cable on Slopes”
– “Design Considerations for Large Trucks”
• Midwest Pooled-Fund States Study “Development
of Guardrail Treatments at Intersecting Roadways”
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Schedule
• Schedule for Adoption
– Final chapter reviews and Technical
Committee balloting at September 2009
meeting in Delaware
– Ballot to SCOD in Fall 2009
– TCRS to address SCOD ballot
comments, Sept 2010 (or sooner)
– Ballot to SCOH in Fall 2010 (or sooner)
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AASHTO Manual for
Assessing Safety Hardware
(MASH)
Technical Committee on Roadside Safety
AASHTO Subcommittee on Design
Indianapolis, Indiana
July 19-23, 2009
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Background
1962: HRCS Circular 482 – one-page document, specified
vehicle mass, impact speed, and approach angle for
crash tests
1973: NCHRP Report 153 – 16-page document, based on
technical input from 70+ individuals and agencies
and a special ad-hoc panel
1978: TR Circular 191 – addressed minor issues
1980: NCHRP Report 230 – 36-page document, brought
procedures up to date with available technology and
practices, updated the evaluation criteria
1993: NCHRP Report 350 – Comprehensive update of 230
2009: Manual for Assessing Safety Hardware (MASH)
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MASH Summary of Changes
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Test matrices and conditions
Test installation
Test vehicle specifications
Evaluation criteria
Test documentation
In-service performance evaluation
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Test Matrices and Conditions
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Small car impact angle (20 degree to 25 degree).
Impact speed for single unit truck test (80
km/h [50 mph] to 90 km/h [56 mph]).
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Impact angle for terminals and crash
cushions (20 degree to 25 degrees).
Gating terminal/crash cushion (Reduce angle
from 15 degrees to 5 degrees).
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Mid-size car test (Add 1500A test vehicle for
staged impact attenuation devices).
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Test Matrices and Conditions
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Barrier Testing Heights (Establish max. for
small vehicle and min. height for pickup test)
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Critical Impact Points (CIPs) for reverse
direction impacts
 TMA optional tests to mandatory (Define
max/min truck weight, control ballast shifting and vehicle
braking)
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Variable message sign and arrow board
trailers (Require same test criteria as TMAs)
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Test Matrices and Conditions
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Support structures and work zone traffic
control devices (Add light truck test in addition to
the small vehicle testing criteria)
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Longitudinal channelizing barricades
(Add new category and recommended test matrix)
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EDR data collection (Provide data on impact
conditions and accelerations from vehicle)
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Test Installation

Soil Condition (soil type, gradation, compaction and
density)
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Embedment of Posts (not necessary
with
reporting of soil conditions)
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Components (provide documentation of components
used)
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Installation Lengths (document length of test
installation)
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Test Vehicles
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Test vehicles (change small vehicle and pickup)
 Single unit truck mass (from 18000 # to 22000 #)
 Light truck test vehicle (Min. c.g. height of 28 inches)
 Vehicle age (six years older or less)
 Truck box attachment (limit detachment, reduce
inconclusive testing results)
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Vehicle damage (document external vehicle crush
damage using NASS procedures)
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Crushable nose characteristics (develop updated
surrogate vehicle testing from 1981 Volkswagen Rabbit)
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TMA support vehicle (Report maximum weight of
support vehicle)
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Evaluation Criteria
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Occupant risk (Modify calculations for Occupancy
Impact Velocity and Ridedown Acceleration with vehicle
yawing)
Windshield damage (Provides more quantitative criteria;
apply criteria to structural support devices the same for
work zone devices)
Occupant compartment damage (Set objective criteria)
Marginal pass (Strictly pass or fail criteria results)
Maximum roll angle (Roll and pitch angle at 75 degrees)
Exit conditions (Report lane intrusions and exit angle
with exit box criteria)
Vehicle rebound for crash cushions (reporting criteria)
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In-Service Evaluation
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Encourage in-service evaluation to demonstrate
satisfactory field performance.
Pool resources (partnering) between State
proprietary device manufacturers.
Disseminate information through resource
channels like National Technical Information
Services (NTIS), FHWA regional resource centers,
and State pooled fund consortiums.
Consider the establishment of new national center
on in-service evaluation.
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Full Scale Crash Tests
Under NCHRP 22-14(02)
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Conducted several full-scale crash tests of
existing hardware, including:
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Strong Post W-Beam System
Midwest Guardrail System
New Jersey Shaped Concrete Barrier
F-Shape temp. concrete barrier with 3-loop connection
Iowa Transition
Tangent Guardrail terminal
New Jersey Shaped Concrete Barrier (32 inches),
failed TL-4 under MASH
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AASHTO/FHWA Joint
Implementation Plan
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All highway safety hardware accepted
using criteria contained in NCHRP 350
may remain in place and may continue to
be manufactured and installed.
Highway safety hardware accepted using
NCHRP Report 350 criteria is not required
to be retested or recertified using MASH
criteria.
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MASH Implementation
If highway safety hardware that has been
accepted by FHWA using criteria contained
in NCHRP Report 350 fails testing using
MASH criteria, AASHTO and FHWA will
jointly review the test results and
determine a course of action.
 Upon adoption of MASH by AASHTO, any
new highway safety hardware not
previously evaluated shall utilize MASH for
evaluation and testing.
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
MASH Implementation
Any new or revised highway safety
hardware under development at the time
the MASH is adopted may continue to be
tested using the criteria in NCHRP 350.
 However, FHWA will not issue acceptance
letters for new or revised highway safety
hardware tested using NCHRP Report 350
criteria after January 1, 2011.
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MASH Implementation
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Agencies are encouraged to upgrade
existing highway safety hardware that has
not been accepted under NCHRP Report
350 or MASH:
– during reconstruction projects,
– during 3R projects, or
– when the system is damaged beyond repair.
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MASH Implementation
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Highway safety hardware not accepted
under NCHRP Report 350 or MASH with no
suitable alternatives available may remain
in place and may continue to be installed.
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Contact Information
Keith A. Cota, Chairman
AASHTO Technical Committee on Roadside Safety
New Hampshire DOT
Hazen Drive, PO Box 483
Concord, NH 03302-0483
Tel: 603-271-1615
Email: [email protected]
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