Part 1 -Topics of Interest to State DOT Safety Engineers

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Part 1 -Topics of Interest to State DOT Safety
Engineers

• CE 552
• Monday, April 16, 2007

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State Highway Safety Engineers

• 268 subscribers
• Who are these folks?
• How many states have a safety engineer?
• The list serve http//statehighwaysafetyengineers
  .org
• Topics

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Topics

• 2004
• Rumble strips
• 2005
• Context Sensitive Design
• Work Zones
• Safety Performance Measures
• Decel Lanes for Median Crossovers
• Top 5 High Risk Roads
• Signal Clearance Timing
• Safety Accountability
• Safety Countermeasure Effectiveness Studies
• High Speed Signals
• Raised Pavement Markers as projectiles
• Context Sensitive Solutions-Design Exceptions
  Mitigation Measures
• Safety Belt Usage
• Empirical Bayes and EB adjustment in the after
  period
• State Capabilities for mapping local crashes
• Collision Diagramming Tools
• Speed Limit increase on High Speed Roads

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2004
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Nevada Fatality Rate per 100MVM
Rumble Strips
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Nevada Fatality Rate per 100,000 Population
Rumble Strips
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Hazard Elimination Program Project Examples
Rumble Strips

• Rural Milled Rumble Strip Project
• Installed in 1998
• Over 700 miles of rural roadway on the Interstate
  and US routes

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Nevada Interstate Rural Fatal Rates
Rumble Strips
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2005
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Context Sensitive Design - Exceptions

• FHWA developing guidance for design exceptions
• for example, a design exception is necessary for
  design speed.  Did the agency take any mitigation
  measures, such as
• lowering the posted speed limit,
• taking geometric design measures (such as
  narrowing the cross section) or 
• traffic calming measures to self-regulate
  operating speeds, etc.
• looking for good case studies for the
  following design criteria
• design speed
• lane width
• shoulder width
• bridge width
• horizontal alignment
• vertical alignment
• grade
• stopping sight distance
• cross slope
• superelevation
• vertical clearance
• horizontal clearance (not clear zone)

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TRB Circular on Context Sensitive Design Around
the Country
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Work Zone Speeding Fines

• North Carolina
• 250 (has to meet specified criteria)
• in addition to any moving violation fines/points
• Illinois
• 375 minimum for the first offense
• 1,000 minimum for the 2nd offense, plus 90 day
  suspension of license.
• Ohio
• up to 150 plus court costs

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Collision Diagramming Tools

• using intersection magic and wondering if there
  is other similar products that might better serve
  their needs
• AIMS GIS Accident Software would need
  extensive modification to be compatible with
  PENNDOT Crash Records System
• Easy Street Draw (for input not the same thing)

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Before-After Methods for Safety Evaluations

• Search for when improvement was made data
• Debate between EB and simpler? Before and After
  methods (mainly practitioner/researcher) - Which
  research approach is better?
• B/A, Yoked pairs, control group, FB
• EB better than CG, but only slightly
• Griffith paper (2 pages) Discussion of Two
  Methodologies for Conducting Before-After Safety
  Evaluations (EB and CG)
• Persaud and Lyon paper (13 pages) EMPIRICAL
  BAYES BEFORE-AFTER SAFETY STUDIES LESSONS
  LEARNED FROM TWO DECADES OF EXPERIENCE
• Tell the story about bias on reviewing papers!
  (Moreno, 7 and 24 Oct 2005)
• How much influence should the research community
  have on the conduct and publication of research
  studies?
• Apply EB adjustment in the after period?

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Speed Limit Changes
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Speed Limit Changes (cont.)
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Speed Limit Changes (cont.)

• Minnesota study
• five years before and 5 years after changes
  (1997).
• large group of highways that stayed the same
  (8,728 mi of 55 mph)
• This "control group" showed fatal crashes going
  down by 3
• 16 when rate adjusted
• roads that went from 55 to 65 (primarily rural
  expressways - 815 mi) showed a 93 increase in
  fatal crashes!!
• Even rate adjusted, was a 54 increase
• roads that went from 65 to 70 (rural interstate -
  726 mi) showed 70 number
• 32 rate increases!
• NCHRP study controversial not released as
  report (web only)
• http//gulliver.trb.org/news/blurb_detail.asp?id6
  069

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Speed Limit Changes (cont.)

• 80 mph speed limit in Texas
• Engineers calculate that drivers burn 7 more gas
  per mile for every 5-mph increase in speed above
  60 mph
• Texans calculate that their Hummers need bigger
  gas tanks
• 85 of drivers averaging 80 mph, 5 mph above the
  current 75-mph speed limit

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Speed Limit Changes (cont.)
See full report here
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Safety Effectiveness of HIGH Speed Traffic
Signals
Souleyrette and Knox
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Safety Belt

• Fines and Court Costs For Not Wearing
• Economic Costs of Low Usage

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Informal survey of 50 state highway safety
engineers, 12/2005
Top 5 - Do states collect data on all roads???

• Reg Souleyrette, Iowa State University
• Co-chair, TRB ABJ60
• Spatial Data and Information Sciences

Draft
R Souleyrette, 11/2005
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Draft
State highway crashes mapable
Yes ??? No response
R Souleyrette, 12/2005
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seldom have local ADT, MP not always accurate,
only 30 officer reported, some city crashes
located
street address and GPS sometimes recorded on
locals
link-node mile offset, GQL
crashes in counties and major cities by int.
node others by city only
state police geocode 70 (65 accurate) on state
roads, very little local road attributes
started using GPS
Tribal and BIA data problematic, county by
section only, city by road number
all have road ID, not all have MP

Uses some private geodata
logmile to GPS problematic, no local attributes
may not be mapped - report contains various road
names, working on base map


local road problematic (45 OK)
report available
Crashes not mapped in 2 counties and independent
cities upgrading to GIS but wont have
attributes on 11K miles

Draft
Attributes on HPMS sample only
70 of crashes mapped

Local crashes mapable?
80 of crashes mapped and growing

need for local crash location has been contended
Yes ??? No No Response
working on using GPS and e-capture
Some districts have some GIS capabilities
Working on it
R Souleyrette, 12/2005
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Raised Pavement Markers

• Snow plow issues
• Pavement failure
• Potential projectile?
• See http//www.trb.org/news/blurb_detail.asp?id61
  68
• Alternatives
• 3 foot section of milled in wet reflective tape
• Epoxy and/or Polyurea markings
• Recessed markers
• delineators on guardrail and median guard cable
• installing edgeline stripes (and some centerline
  stripes) in a rumble strip
• NCHRP Study on Pavement Markings and Safety
• relationship of enhanced pavement markings and
  safety

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Safety Accountability

• Should safety performance be part of job
  performance?
• Chief Engineers
• District engineers
• even CEO's (Directors/Secretaries of Transp.)

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Remember usRAP?
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Signal Clearance timing safety study

• Richmond, VA, implemented amber red clearance
  intervals recommended by ITE
• includes a standard all red clearance interval of
  2 seconds.
• injury rates decreased from 4,000 injuries per
  year to 2,600
• Minnesota
• yellow approach speed divided by 10
• 3 seconds in a 30 zone, up to 6.5 seconds for a
  rural expressway
• Grades and other factors - additional
  consideration
• time the all red for a divided highway
  intersection with a wide median
• last vehicle entering on the side street is a
  large truck
• typically don't provide an all red long enough
  for that truck to fully clear,which could be 4 to
  5 seconds
• long enough so that the truck is fully visible to
  traffic getting the green on the far roadway
  (2-2.5 seconds)

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Paving deceleration lanes on freeway crossovers
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2006
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Risk Factors from CODESrisk of fatal or major
injury relative to speed, age, belt usage , DUI ,
hitting a fixed object  etc
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safety challenges for AASHTO Policy
Recommendations

• Efforts to reduce to the fatality rate to the
  goal of 1.0 fatalities per 100 million VMT  have
  been and will continue to be face several
  challenges. These include
• 1. An aging driver population 
• 2. Increased motorcycle registration
• 3. More high speed congestion 
• 4. Increased SUV and pick-up truck sales
• 5. More multi tasking/distracted drivers 
• 6. Increased rural speed limits
• 7.A disproportionate increase in heavy truck
  volumes
• 8. Increased immigration is adding  additional
  "challenged"  drivers to the roadway 
• 9. A Reduction in enforcement officer staffing
  due to budget cuts and military call ups
• 10. A reduction in  rural volunteer emergency
  medical response staffing 
• 11. A reduction in rural hospital emergency rooms
  and trauma centers . 
• 12. An increase in recreational bicycling ,
  jogging and walking along our roadways  
• 13.  Driver / citizen apathy to authority, laws
  and regulations  

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Median Cable

• guard cable was effective (i.e. it did not allow
  a vehicle to cross into the opposing lanes) 94
  of the time
• Failures often include
• large trucks,
• extremely high speeds, or
• steep angles of collision with the cables
  (sometimes caused by running off the road right,
  and then overcorrecting left).
• Motorcycles?
• traffic signal analogy
• C-shaped posts?
• See South Dakota Road
• Design Manual Chapter 10

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See also http//cms.transportation.org/?siteid57
pageid1031 and http//www.ncdot.org/doh/preconstr
uct/traffic/reports/AASHTO/default.html
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Median Cable (cont)

• References
• http//cms.transportation.org/?siteid57pageid10
  31
• http//www.ncdot.org/doh/preconstruct/traffic/repo
  rts/AASHTO/default.html
• 2006 FHWA Brochure http//www.fhwa.dot.gov/crt/mar
  ketready/cable.pdf
• 2004 WSDOT Brochure
• 2003 NCDOT Brochure    
• 2005 Public Roads http//www.tfhrc.gov/pubrds/05ja
  n/06.htm
• 2006 NCDOT Update
• http//www.ncdot.org/doh/preconstruct/traffic/repo
  rts/AASHTO/default.html
• TIG-CMB Information Module Outline
• ODOT - 2 Year in service evaluation  
• NCDOT Design Specs    
• Midwest States Scanning Tour     -    
  http//sftp.cee.uiuc.edu/research/tol/TOLseries18.
  htm

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Where it didnt work (NJ)
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Where it did work (UT)
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Status of Strategic Hwy Safety Plans and
challenges DOT's are incurring
See Two pager
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Miscellaneous

• Safety Engineers Peer Exchange Notification
• Work zone delay - assessment, policy
• Survey ITS applications to improve highway
  safety (no responses)
• STOP AHEAD Pavement Marking

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Move Over, Slow Down

• 700 law enforcement officers have died during
  traffic incidents in the past ten years
• http//www.dps.mo.gov/
• http//www.dps.mo.gov/home/MoveOverVideo.htm