TH 23CSAH 7 Road Safety Audit

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TH 23/CSAH 7 Road Safety Audit
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TH 23/CSAH 7 Road Safety Audit

• Background
• Data Collection and Review
• Field Review Observations
• Potential Mitigation Measures

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Background

• Purpose and Need for Road Safety Audit
• Intersection identified by City as safety problem
  location
• Recent fatal bike crash
• Road safety audit can identify potential safety
  solutions
• Pending Development north of TH 23
• Road Safety Audit Team
• Five Mn/DOT experts
• Minnesota State Patrol officer
• SEH traffic engineer

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Data Collection and Review

• Meeting with District 8 and Other Stakeholders
• Intersection Geometry and Traffic Control
• 4-lane expressway intersecting 2-lane road
• 55 mph speed limit on TH 23
• 40 mph speed limit on CSAH 7 north of TH 23 and
  55 mph speed limit on CSAH 7 south of TH 23
• Right and left turn lanes on TH 23 right turn
  lanes on CSAH 7
• Narrow median crossover (about 42 feet from edge
  to edge)
• TH 23 is uncontrolled
• Stop sign control for CSAH 7 and yield sign
  control for median crossover
• Bike crossing across east leg of intersection

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Data Collection and Review

• Traffic Volumes
• 5,800 to 5,900 veh./day on TH 23
• 3450 to 740 veh./day on CSAH 7
• 2,200 veh./day on CSAH 7 north of Country Club
  Drive
• 2,000 veh./day on Country Club Drive
• Future traffic increase due to anticipated
  residential development north of TH 23
• Intersection does not currently meet MMUTCD
  signal warrants

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Data Collection and Review

• Crash Data
• 17 crashes in approximately five year period
• One fatal crash and 11 crashes involving injuries
• Intersection crash rate is four times the
  statewide average rate
• 14 crashes were right angle type
• 12 crashes involved vehicles pulling away from
  median crossover

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Field Review Observations
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Field Review Observations

• Geometric Design and Lighting
• Curve in CSAH 7 north of TH 23 and curve in CSAH
  7 north of Country Club Drive
• Jog in CSAH 7 north of TH 23
• Vehicles waiting in median left turn lanes can
  limit sight distance for other traffic
• Limited storage space for vehicles waiting in the
  median crossover
• Radii in NW and SE corners is tight for large
  trucks
• No end treatment for bridge railings on CSAH 7
  bridge south of TH 23
• Existing street lighting

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Field Review Observations

• Signing and Pavement Markings
• Undersized signing for expressway intersection
  conditions
• SB STOP sign and median DO NOT ENTER signs
  mounted too low
• ONE WAY sign obscures shape of YIELD signs on
  median
• NB CSAH 7 STOP AHEAD sign too small
• Good route marker/directional signing identifies
  intersection
• Approaches have centerline, edge line, and lane
  line markings
• No pavement markings in median crossover area
• No yield line markings
• BIKE CROSSING signs are 30x30
• Delineator color wrong on curves

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Field Review Observations

• Other Observations
• No off-road pedestrian or bike facilities
• No development in any corners of intersection

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Potential Mitigation Measures

• General
• Grouped into short-term and long-term
  improvements
• Short-term measures not guaranteed to be
  successful

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Potential Mitigation Measures

• Short-Term Improvements
• Upgrade signing to meet current expressway
  intersection signing practices
• Increase size of NB STOP AHEAD sign on CSAH 7
• Add BIKE ROUTE sign with LEFT ARROW sign on EB TH
  23
• Increase size of BIKE CROSSING signs to 36x36
• Add flashers to BIKE CROSSING signs
• Change delineators on curves
• Add rumble strips along TH 23 edge lines
• Mark yield lines in the median crossover
• Reconstruct median ends and add defined pathway
  for bike crossing
• Add HAWK signal for bike crossing
• Increase corner radius in NW and SE corners of
  intersection to accommodate large trucks
• Add crashworthy end treatment to CSAH 7 bridge
  railings

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Potential Mitigation Measures

• Long-Term Improvements
• Change intersection to grade-separated
  interchange
• Reconfigure intersection to provide offset left
  turn lanes in median area
• Add free right and acceleration lane for SB CSAH
  7 movement
• Reconfigure intersection to ¾ access intersection
  
• Reconstruct and realign CSAH 7/Country Club Drive
  intersection

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Potential Mitigation Measures

• Other Considerations
• Provide sidewalks or trails along roadways
• Form Safe Communities Coalition

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Summary

• Alternative choices of improvements provided and
  need more detailed evaluation by District 8 staff
• Short-term improvements are only temporary
  solution
• Permanent solution can only be achieved through
  long-term improvement