TRIBES AND TRANSPORTATION

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• TRIBES AND TRANSPORTATION
• AUDITS
• Dick Larson

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TRIBES and TRANSPORTATION Road Safety
Audits - October 18, 2006 The Mille Lacs County
Experience By Richard C. Larson P.E.
County Engineer
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• I promise myself, my family, and my fellow
  drivers
• To fasten all seatbelts in my vehicle
• To not tailgate or retaliate
• To relax and avoid road rage
• To look both ways twice at stop signs
• To concentrate on my driving
• To drive sober

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TZD

• FOUR SAFETY FACTORS
• Education
• Engineering
• Enforcement
• Emergence Medical Services

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TZD

• FOUR SAFETY FACTORS
• Education
• Engineering
• Enforcement
• Emergence Medical Services
• EVERYONE!

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Road Safety AuditsA Comprehensive Highway Safety
Plan Program

• TH 95 Safe Communities Project
• Mille Lacs County Audit Project
• District 3 Audit Project

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Minnesota DOT Districts
MINNESOTA DOT DISTRICTS
M
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DISTRICT
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Audit Process Flow Chart
Review Background Information - Crash Data -
Volume Data - Road System Data - Review Plan
Field Review Observations
Select Team Hold Meeting With Road Authority
Draft Technical Memo - Observations -
Deficiencies - Suggested Improvements
Review Draft T.M. Presentation to County and
Mn/DOT Staff
Final Technical Memo
Call to Action Written Response by Counties
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CHSP County Grant Program

• MN DOT District 3 Audit Project
• 13 Counties
• Focused on County Road, State Highway road
  intersections
• Included general review of sample roads
• CH2M Hill is the consulting firm

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Mille Lacs County Intersections
TH 169
TH 169
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TH 23
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• TH 169 CSAH 11
• TH 169 CSAH 9
• TH 169 CSAH 8
• TH 169 CSAH 12
• TH 169 CSAH 13
• TH 23 CSAH 18
• TH 23 CSAH 2
• TH 23 CSAH 1
• TH 95 CSAH 29
• TH 95 CSAH 7

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General Audit Observations and Suggestions
District 3 Road Safety Audits
District 3 Road Safety Audits
September 25, 2006
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General Audit Observations

• Intersection sight distance restrictions.
• Mn/DOTs typical layout of guide signs intercepts
  sight lines from stop signs.
• Layout/design of traffic control devices on
  county highway approaches are not consistent.
• Pavement markings along the county system were
  generally in fair to poor condition.
• Virtually no enforcement presence on the county
  system.
• Street lights were in place at fewer than 5 of
  the intersections reviewed in the Audit.

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General Audit Observations

• Signs along the county system were generally in
  good condition, but only one county has a written
  policy addressing schedules for inventory,
  repair, and replacement.
• The design and application of traffic control
  devices at combination right-turn and bypass
  lanes was not consistent.
• Expressway intersectionsthe primary factor
  contributing to crashes was the lack of adequate
  gaps.
• Signs at T-intersections were not consistent.
• Improvements can be made to reduce run-off-road
  crashes.

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TH 169 CSAH 12 Another good candidate for
lighting. High volumes, 33 nighttime crashes.
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LOOKING WEST FROM CSAH 12
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LOOKING WEST FROM CSAH 12
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LOOKING SOUTH DOWN TH 169
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LOOKING WEST ACROSS INTERSECTION
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LOOKING EAST FROM CASH 12
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LOOKING EAST FROM CSAH 12
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LOOKING EAST FROM CSAH 12
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TH 169 at CSAH 11, CSAH 9, CSAH 8, CSAH 12, and
CSAH 13 These five intersections have 98 angle
crashes 2.5 times what is expected. Consider
interim measures to address conflicts and lack of
gaps. Consider creating offset Ts, indirect
turns, inside acceleration lanes, etc.
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Signing
Revised Typical Layout of County Highway Traffic
Control Devices
Add can delineators to Stop sign
36, reserve 48 for intersections with
documented deficiency and where there are RR
grade crossings on the CH approach
Stop Bar, 12 to 24 wide, 8 to 12 back from
edgeline
½ distance between Stop Ahead and Stop

• Prioritized/Phasing
• Stop bar
• Stop sign
• Junction sign
• Stop Ahead Message
• Stop Ahead Sign

Provide three devices indicating up coming
intersection
½ distance between Stop Ahead and Junction sign
450 (min.) to 750 back, 1 size larger than Stop
(up to 48)
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TH 1 69 CSAH 9 Freeway styleguide signs on
TH 1 69.
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Priorities for Mille Lacs County

• Develop/adopt sign maintenance policy with
  specified replacement schedule
• Develop/adopt pavement marking maintenance policy
  with specified repainting schedule
• Work with Mn/DOT to identify/implement interim
  measures along TH 169 that addresses
  crossing/turning conflict problem.
• Work with Mn/DOT to improve intersection signing
• Consider implementing a rural street lighting
  program (night crashes over represented at 2 out
  of 10 intersections)
• Consider implementing low cost road departure
  mitigation strategies.

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• Intersection Sight Distance
• Observation
• Sight distance was restricted at numerous
  locations.

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• Observation
• Mn/DOTs typical layout of intersection guide
  signs intercepts sight lines from the stop signs.

Suggestion Develop/adopt a revised typical layout
that relocates all of the signs away from the
intersection.
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• Intersection Sight Distance
• Suggestions
• remove or relocate sight obstructions.
• signs
• vegetation
• utilities
• paint or reposition stop bar to improve sight
  lines.
• at a small number of locations, consider
  implementing long term geometric improvements
  that will improve intersection sight distance.

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Signing
Existing Typical Layout of Trunk Highway Guide
Signs
State Trunk Highway
Some intersections also contain Adopt A Highway
signs mixed with intersection guide signs.
County Highway
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Signing
Revised Typical Layout of Trunk Highway Guide
Signs
6-8 off edge of edgeline
State Trunk Highway
Relocate all Adopt A Highway signs that are
mixed in with the sequence of guide signs on the
approach to intersections.
County Highway
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Sight distance at stop sign.
Sight distance if stop bar is placed ahead of
stop sign.
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CHSP County Grant Program

• MILLE LACS County Audit Project
• County Road intersections
• Evaluation of County crash data
• SRF Consulting firm

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LOOKING SOUTH ON CSAH 1
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LOOKING NORTH ON CSAH 1
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LOOKING NORTH ON CSAH 1
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LOOKING EAST AT INTERSECTION AT STOP BAR
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LOOKING EAST IF STOP BAR WERE MOVED NORTH
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CSAH 13 and CSAH 1

• This intersection is all-way stop controlled
• Located in southeast part of county
• One personal injury in past 5 years
• Northbound vehicle failed to stop
• Sheriff notes intentional running a problem
• Existing 30 inch signs
• No delineation on sign posts

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CSAH 13 and CSAH 1

• Southbound stop sign is 12 from pavement
• Tree line southeast quadrant restrict sight
• Drop off to catch basin south east quadrant
• No Passing sign missing for northbound traffic

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CSAH 13 and CSAH 1

• Highly Recommended
• Trim trees to improve sight distance
• Relocate stop sign further north
• Potential High Impact
• Install No Passing Sign for northbound travel
• Suggestions
• Delineate catch basin in southeast quadrant

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CSAH 13 and CSAH 1
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• More Information web site
• www. tdz.state.mn.us/

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2005 County Crash Data
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Road Safety Audit Review Team
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• Traffic Control Devices Along County Highway
  Approaches
• Observation
• approaches to state highways was not consistent
  from road to road The layout/design of traffic
  control devices along county highway or county to
  county.

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• Traffic Control Devices Along County Highway
  Approaches
• Suggestions
• Develop/adopt a consistent layout design for
  traffic control devices along the county highway
  approaches.
• Provide 3 devices indicating an upcoming
  intersectionSTOP AHEAD sign and pavement message
  and the highway junction sign.
• Use a 36-inch stop signone size larger than the
  30-inch minimum.
• Reserve the use of 48-inch stop signs for unusual
  locations (such as vicinity of railroad
  crossings) or where there is a documented run the
  stop problem.

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• Traffic Control Devices Along County Highway
  Approaches
• Suggestions
• Use a second, left side stop sign on wide
  approaches and/or where it is more than 5 miles
  from the nearest stop sign.
• Transverse rumble strips are not recommended
  because they have not been proven effective, they
  address a factor that contributes to a minority
  of intersection crashes and most encountered in
  the field were barely audible because of lack of
  maintenance.

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Signing
Existing Typical Layout of County Highway Traffic
Control Devices
Stop Bar (found at 10)
30, 36 or 48

• Issues
• STOP sign size
• STOP bar
• Transverse rumble strips
• Junction sign
• Stop ahead

(found at 10)
Transverse Rumble Strips
(found at 10)
(found at 10)
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Pavement Markings

• Observations
• Pavement markings along the county system were
  generally in fair to poor condition.
• Most counties were on a 2- to 4-year cycle for
  repainting center and edge lines.
• It appears that over these extended periods of
  time, snow plows significantly reduce the
  retroreflective quality of the markings.

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Pavement Markings

• Suggestions
• Reevaluate maintenance priorities and policies in
  order to increase the frequency of repainting,
  especially the most critical elements of the
  systemcenterlines and edge lines on horizontal
  curves.
• To improve risk management efforts, consider
  developing and adopting a written pavement
  marking maintenance policy that identifies a
  countys priorities, a re-striping schedule, and
  a goal/date for completion each year.
• A copy of Cass Countys policy is included in the
  Appendix.
• Consider evaluating the use of edgeline rumble
  stripes. Initial research indicates better
  initial wet pavement retroreflectivity and longer
  service life of the glass beads (the plows cant
  get at the beads on the nearly vertical faces in
  the troughs).

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Edgeline painted over rumble strips.
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Enforcement Observations

• During 13 days in the field, there was virtually
  no enforcement presence along the County System.
• County Sheriffs Departments appear to be
  understaffed given their variety of assignments
  and the miles of road they have to patrol.
• Mn/DOT ATR data indicates an 85th percentile
  speed of almost 66 mph along county highways with
  almost 12 of drivers going faster than 10 mph
  over the limit.
• This 85th percentile speed on county highways is
  similar to 2-lane state highways, but the
  fraction of drivers over 65 mph is more than
  twice that on state highways.

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Enforcement Suggestions

• Refocus enforcement priorities in order to
  increase the presence and threat of enforcement
  along county highways. The goal is to reduce the
  level of aggressive driving.
• The Minnesota Speed Management Program, with
  increased levels of enforcement, has reduced the
  fraction of drivers over 65 mph by approximately
  40. A similar speed enforcement effort on the
  County System would likely have similar results.

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Street Lighting

• Observation
• Street lights were noted to be in place at fewer
  than 5 of the intersections in the Audit.
  However, the fraction of night crashes was above
  the statewide average at almost one-half of the
  intersections.

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Street Lighting

• Suggestions
• Proactively undertake a program to increase the
  use of street lights at rural intersections.
• Establish a short-term goal of doubling the
  number of rural intersections with street lights
  and a long-term goal of 25.
• Street lights are one of the high priority
  intersection strategies in Minnesotas CHSP and
  are proven to be effective (Mn/DOT/LRRB Report
  1999-17).
• Street lights
• makes drivers more aware of intersection.
• improves perception-reaction time.
• increases nighttime sight distance.

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ign Maintenance
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• Several sign post installations were observed
  that do not appear to be consistent with current
  crash test standards.

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Sign Maintenance

• Suggestions
• Develop and adopt a written sign maintenance
  policy that documents schedules for field
  inventories (including night inspections),
  recurring sign replacement (to address MUTCD
  requirements regarding retroreflectivity), and a
  prioritized approach to repair damaged signs. (A
  copy of Cass Countys Policy is included in the
  Appendix).

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Combination Right-Turn Lanes and/or Bypass Lanes

• Observations
• Combination right-turn and/or bypass lanes were
  observed at a number of both 4-leg and
  T-intersections, however, the design and
  application of traffic control devices varied
  from intersection to intersection.
• Bypass lanes and right-turn lanes should be
  signed and marked consistent with Mn/DOT
  guidelines.
• Geometry of bypass lanes and turn lanes should be
  consistent with Mn/DOT guidelines (length, width,
  and taper).

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Mn/DOT Road Design Manual
Broken white markings 3-foot line 12-foot skip
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Expressway Intersections

• Observations
• 16 expressway intersections were reviewed. The
  average crash rate for this group is at the
  statewide average (0.5) and the average crash
  frequency is 3 crashes/intersection/year. This
  does not indicate any particular crash problem.
• 2 crash characteristics standout. First, the
  fraction of angle crashes (45) is almost twice
  the statewide average (28) and nighttime crashes
  are overrepresented.
• It appears that most of these crashes are
  unrelated to intersection geometry and traffic
  control. The primary contributing factor appears
  to be a lack of adequate gaps.
• Research has shown that safety of at-grade
  expressways degrades (crash rates rise and the
  fraction of intersection-related crashes
  increases) when volumes on the expressway exceed
  20,000 vpd and/or volumes on the minor road
  exceed 2,000 vpd. The demand for gaps exceeds
  the availability of adequate gaps.

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Lack of gaps
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Expressway Intersections

• Suggestions
• Develop, adopt, and implement a corridor
  management plan that specifically addresses the
  issue of gaps and includes
• long term solutions
• construct interchanges at strategic locations.
• close adjacent intersections.
• lower-cost solutions
• close medians at selected locations
  (right-in/right-out).
• construct indirect intersections.
• interim improvements
• freeway-size/style guide signs
• accel lanes
• lighting

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T-intersections

• Observation
• The T-intersections reviewed were not consistent
  in the layout or application of highway signs.
  Some had route signs opposite the minor leg, some
  had confirming route signs along the TH legs and
  some had large arrow signs.
• Suggestions
• Install route markers opposite the minor leg to
  help define the intersection area.
• If these route markers are installed, consider
  removing the typical confirming route signs to
  reduce sign clutter in the intersection area.
• Adopt a practice of installing any sign on the
  far side of the minor approach to either the left
  or right of the extension of the approach lane in
  order to reduce nuisance hits.

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un-off-Road Crashes

• Observations
• The cross section and clear zones along the
  County Highway System were generally rated fair
  to very good (and in several cases better than
  along nearby state highways). However, a review
  of the distribution of crash types along a sample
  of county highways in District 3 (approximately
  250 miles) found that road departure crashes are
  the most prevalent type of crash.
• A review of statewide crash data indicates the
  need to increase efforts to address road
  departure crashes
• 959 fatal ROR crashes between 1998 and 2002 (34
  of all fatal crashes).
• Over half occurred on county and township roads
  (511 of 959, 53).
• Most common route type was CSAH roadways (385 of
  959, 40).
• ROR crashes are most often rural (693 of 959,
  72).

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Run-off-Road Crashes

• Suggestions
• Develop county safety programs that proactively
  implement low-cost strategies that are proven to
  reduce the number of road departure crashes.
  These include
• paved shoulders
• shoulder rumble strips
• the safety wedge
• upgrading safety hardware
• enhanced pavement markings
• regrading slopes
• providing clear recovery area

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Conclusion

• Most county highways were in relatively good
  condition. Notable exceptions
• pavement markings
• shoulders
• Tort liability issues prepare a written
  response.
• acknowledge the suggestions.
• identify those you decide to implement (and a
  schedule).
• identify those you decide not to implement (and
  cite a reason).
• Risk management technique adopt written
  maintenance policies.

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Conclusion

• Analytical techniques need to be improved.
• current techniques tend to direct safety
  investment to urban signalized intersections,
  which are not the characteristics associated with
  the location of most serious crashes.
• new analytical techniques need to be used that
  direct the safety investments to locations where
  the deficiencies are the greatest (but the
  numbers arent). Rural, 2-lane facilities on the
  local system.
• County Highway Departments should consider
  developing stand-alone Safety Improvement
  Programs.
• Develop a prioritized implementation strategy.
• traffic control devices add missing devices.
  Upgrade existing as part of scheduled maintenance
  programs.

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• THE END
• Questions?