HSM Tables, Case Studies, and Sample Problems Table of Contents

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1 HSM Tables, Case Studies, and Sample Problems Table of Contents Chapter 10 Tables: HSM Default Tables Local Values (Michigan)... 1 Chapter 11 Tables: HSM Default Tables Local Values (Michigan)... 5 Chapter 12 Tables: HSM Default Tables Michigan Values Not Available Sample Problem 3-1: Sample Problem 4-1: Case Study 7-1: Case Study 9-1: Case Study 10-1: Case Study 11-1: Chap 10 Sample Problem 1: Chap 10 Sample Problem 2: Chap 10 Sample Problem 3: Chap 10 Sample Problem 4: Chap 10 Sample Problem 5: Chap 10 Sample Problem 6: Chap 11 Sample Problem 1: Chap 11 Sample Problem 2: Chap 11 Sample Problem 3: Chap 11 Sample Problem 4: Chap 11 Sample Problem 5: Chap 11 Sample Problem 6: Chapter 10 Sample Problems - Data Entry Tables HSM Chapter 10 Sample Problem HSM Chapter 10 Sample Problem Chapter 11 Sample Problems - Data Entry Tables HSM Chapter 11 Sample Problem HSM Chapter 11 Sample Problem Chapter 12 Sample Problems - Data Entry Tables HSM Chapter 10 Sample Problem HSM Chapter 12 Sample Problem HSM Chapter 10 Worksheets (Sample)

2 HSM Chapter 10 Tables Chapter 10 Tables: HSM Default Tables Local Values (Michigan) Table 10-3: Distribution for Crash Severity Level on Rural Two-Lane Two-Way Roadway Segments plus Michigan Derived Values Percentage of total roadway segment crashes Crash severity level HSM-Provided Values Locally-Derived Values (Michigan) Fatal Incapacitating Injury Non-incapacitating Injury Possible Injury Total Fatal Plus Injury Property Damage Only TOTAL Note: HSM-provided crash severity data based on HSIS data for Washington ( ). Locally-Derived Values provided courtesy of the Michigan Department of Transportation (MDOT). Table 10-4: Default Distribution by Collision Type for Specific Crash Severity Levels on Rural Two-Lane Two-Way Roadway Segments plus Michigan Derived Values Percentage of total roadway segment crashes by crash severity level HSM-Provided Values Locally-Derived Values (Michigan) TOTAL (all Property Total fatal Property Total fatal TOTAL severity levels damage and injury damage only and injury combined Collision type combined) only SINGLE-VEHICLE CRASHES Collision with animal Collision with bicycle Collision with pedestrian Overturned Ran off road Other single-vehicle crash Total single-vehicle crashes MULTIPLE-VEHICLE CRASHES Angle collision Head-on collision Rear-end collision Sideswipe collision Other multiple-vehicle collision Total multiple-vehicle crashes TOTAL CRASHES Note: HSM-provided values based on crash data for Washington ( ); includes approximately 70 % opposite-direction sideswipe and 30% same-direction sideswipe collisions. Locally-Derived Values provided courtesy of the Michigan Department of Transportation (MDOT). Table 10-5: Default Distribution for Crash Severity Level at Rural Two-Lane Two-Way Intersections Michigan Derived Values Percentage of total crashes HSM-Provided Values Locally-Derived Values (Michigan) Collision type 3ST 4ST 4SG 3ST 4ST 4SG Fatal Incapacitating injury Non-incapacitating injury Possible injury Total fatal plus injury Property damage only TOTAL Note: Locally-Derived Values provided courtesy of the Michigan Department of Transportation (MDOT). Chapter 10 Tables 1

3 HSM Chapter 10 Tables Table 10-6: Default Distribution for Collision Type and Manner of Collision at Rural Two-Way Intersections plus Michigan Derived Values Percentage of total crashes by collision type: HSM Default Values Three-leg stop-controlled Four-leg stop-controlled intersections intersections Four-leg signalized intersections Fatal and Property damage Total Fatal and Property damage Total Fatal and Property damage Total Collision type Injury only injury only injury only SINGLE-VEHICLE CRASHES Collision with animal Collision with bicycle Collision with pedestrian Overturned Ran off road Other single-vehicle crash Total single-vehicle crashes MULTIPLE-VEHICLE CRASHES Angle collision Head-on collision Rear-end collision Sideswipe collision Other multiple-vehicle collision Total multiple-vehicle crashes TOTAL CRASHES Percentage of total crashes by collision type: Locally Derived Values (Michigan) Three-leg stop-controlled Four-leg stop-controlled intersections intersections Four-leg signalized intersections Property Fatal Property Fatal Property Fatal and damage Total and damage Total and damage Injury Collision type only injury only injury only Total SINGLE-VEHICLE CRASHES Collision with animal Collision with bicycle Collision with pedestrian Overturned Ran off road Other single-vehicle crash Total single-vehicle crashes MULTIPLE-VEHICLE CRASHES Angle collision Head-on collision Rear-end collision Sideswipe collision Other multiple-vehicle collision Total multiple-vehicle crashes TOTAL CRASHES Note: Locally-Derived Values provided courtesy of the Michigan Department of Transportation (MDOT). Chapter 10 Tables 2

4 HSM Chapter 10 Tables Table 10-8: CMF for Lane Width on Roadway Segments (CMFra) AADT (veh/day) Lane Width (ft) < to 2000 > Table 10-9: CMF for Shoulder Width on Roadway Segments (CMFwra) AADT (veh/day) Shoulder Width (ft) < to 2000 > Table 10-10: Crash Modification Factors for Shoulder Types and Shoulder Widths on Roadway Segments (CMFtra) Shoulder Shoulder width (ft) Type Paved Gravel Composite Turf Note: The values for composite shoulders in this exhibit represent a shoulder for which 50 percent of the shoulder width is paved and 50 percent of the shoulder width is turf. Table 10-11: Crash Modification Factors (CMF5r) for Grade of Roadway Segments Approximate Grade (%) Level Grade ( 3% ) Moderate Terrain ( 3% < grade 6% ) Steep Terrain ( >6% ) Table 10-12: Nighttime Crash Proportions for Unlighted Roadway Segments plus Michigan Derived Values HSM Default Values Locally Derived Values (Michigan) Roadway Proportion of total nighttime crashes by severity level Proportion of crashes that occur at night Proportion of total nighttime crashes by severity level Proportion of crashes that occur at night Type Fatal and Injury pinr PDO ppnr pnr Fatal and Injury pinr PDO ppnr pnr 2U Note: HSM-provided values based on HSIS data for Washington ( ). Locally-Derived Values provided courtesy of the Michigan Department of Transportation (MDOT). Chapter 10 Tables 3

5 HSM Chapter 10 Tables Table 10-13: CMF for Installation of Left-Turn Lanes on Intersection Approaches (CMF2i) Number of approaches with left-turn lanes Intersection traffic control a Intersection type Three-leg intersection Minor road stop control b Minor road stop control Four-leg intersection b Traffic signal Table 10-14: CMF for Installation of Right-Turn Lanes on Intersection Approaches (CMF3i) Number of approaches with left-turn lanes a Intersection type Intersection traffic control Three-leg intersection Minor road stop control b Four-leg intersection Minor road stop control b Traffic signal a Stop-controlled approaches are not considered in determining the number of approaches with left-turn lanes b Stop signs present on minor road approaches only. Table 10-15: Nighttime Crash Proportions for Unlighted Intersections Proportion of crashes that occur at night, pni Intersection Type HSM Provided Values Locally-Derived Values (Michigan) 3ST ST SG Note: Locally-Derived Values provided courtesy of the Michigan Department of Transportation (MDOT). Notes for Tables 8 & 9 for AADT See HSM for determining values Chapter 10 Tables 4

6 HSM Chapter 11 Tables Chapter 11 Tables: HSM Default Tables Local Values (Michigan) Table 11-4: Distribution of Crashes by Collision Type and Crash Severity Level for Undivided Roadway Segments Proportion of crashes by collision type and crash severity level HSM-Provided Values Locally-Derived Values (Michigan) Fatal Fatal Fatal and Fatal and Total and PDO Total and injury injury Collision type injury a injury a PDO Head-on Sideswipe Rear-end Angle Single Other SV run-off-rd, Head-on, Sideswipe Note: Locally-Derived Values provided courtesy of the Michigan Department of Transportation (MDOT). Table 11-6: Distribution of Crashes by Collision Type and Crash Severity Level for Divided Roadway Segments Proportion of crashes by collision type and crash severity level HSM-Provided Values Locally-Derived Values (Michigan) Fatal and Fatal and Fatal and Fatal and Total PDO Total Collision type injury injury a injury injury a PDO Head-on Sideswipe Rear-end Angle Single Other SV run-off-rd, Head-on, Sideswipe Note: Locally-Derived Values provided courtesy of the Michigan Department of Transportation (MDOT). Chapter 11 Tables 5

7 HSM Chapter 11 Tables Table 11-9: Distribution of Intersection Crashes by Collision Type and Crash Severity Proportion of crashes by collision type and crash severity level HSM-Provided Values Locally-Derived Values (Michigan) Fatal Fatal and Fatal and Fatal and Total PDO Total and injury injury Collision type injury injury a PDO Three-leg intersections with minor road stop control Head-on Sideswipe Rear-end Angle Single Other SV run-off-rd, Head-on, Sideswipe Four-leg intersections with minor road stop control Head-on Sideswipe Rear-end Angle Single Other SV run-off-rd, Head-on, Sideswipe Four-leg signalized intersections Head-on Sideswipe Rear-end Angle Single Other SV run-off-rd, Head-on, Sideswipe NOTE: a Using the KABCO scale, these include only KAB crashes. Crashes with severity level C (possible injury) are not included. Locally-Derived Values provided courtesy of the Michigan Department of Transportation (MDOT). Table 11-10: Summary of CMFs in Chapter 11 and the Corresponding SPFs Applicable SPF CMF CMF Description CMF Equations and Exhibits CMF1ru Lane Width on Undivided Segments Equation 11-12, Table and Figure 11-8 CMF2ru Shoulder Width and Shoulder Type Equation 11-14, Figure 11-9, Tables and Undivided Roadway CMF3ru Sideslopes Table Segment SPF CMF4ru Lighting Equation 11-15, Table CMF5ru Automated Speed Enforcement See text Divided Roadway Segment SPF Three- and Four-Leg Stop-Controlled Intersection SPFs CMF1rd Lane Width on Divided Segments Equation 11-16, Table 11-16, Figure CMF2rd Right Shoulder Width on Divided Roadway Segment Table CMF3rd Median Width Table CMF4rd Lighting Equation 11-17, Table CMF5rd Automated Speed Enforcement See text CMF1i Intersection Angle Tables 11-20, CMF2i Left-Turn Lane on Major Road Tables 11-20, CMF3i Right-Turn Lane on Major Road Tables 11-20, CMF4i Lighting Tables 11-20, Chapter 11 Tables 6

8 HSM Chapter 11 Tables Table 11-11: CMF for Lane Width on Undivided Roadway Segments (CMFRA) AADT (veh/day) Lane Width (ft) < to 2000 > Note: The collision types related to lane width to which this CMF applies include run-off-the-road, head-on crashes, and sideswipes. Table 11-12: CMF for Collision Types Related to Shoulder Width (CMFWRA) AADT (veh/day) Shoulder Width (ft) < to 2000 > Note: The collision types related to shoulder width to which this CMF applies include single-vehicle run-off-the-road and multiple-vehicle headon, opposite-direction sideswipe, and same-direction sideswipe crashes. Table 11-13: CMF for Collision Types Related to Shoulder Types and Shoulder Widths (CMFTRA) Shoulder width (ft) Shoulder Type Paved Gravel Composite Turf Table 11-14: CMF for Side Slope on Undivided Roadway Segments (CMF3ru) 1:2 or Steeper 1:3 1:4 1:5 1:6 1:7 or Flatter Table 11-15: Night-time Crash Proportions for Unlighted Roadway Segments HSM-Provided Values Locally-Derived Values (Michigan) Proportion of total night-time crashes by severity level Proportion of crashes that occur at night Proportion of total night-time crashes by severity level Proportion of crashes that occur at night Roadway Type Fatal and injury, pinr PDO, ppnr pnr Fatal and injury, pinr PDO, ppnr pnr 4U Note: Locally-Derived Values provided courtesy of the Michigan Department of Transportation (MDOT). Chapter 11 Tables 7

9 HSM Chapter 11 Tables Table 11-16: CMF for Lane Width on Divided Roadway Segments (CMFRA) AADT (veh/day) Lane Width (ft) < to 2000 > Note: The collision types related to lane width to which this CMF applies include run-off-the-road, head-on crashes, and sideswipes. Table 11-17: CMF for Right Shoulder Width on Divided Roadway Segments (CMF2rd) Average Shoulder Width (ft) CMF Table 11-18: CMF for Median Width on Divided Roadway Segments without a Median Barrier (CMF3rd) Median Width (ft) CMF Table 11-19: Night-time Crash Proportions for Unlighted Roadway Segments HSM-Provided Values Locally-Derived Values (Michigan) Proportion of total night-time crashes by severity level Proportion of crashes that occur at night Proportion of total night-time crashes by severity level Proportion of crashes that occur at night Roadway Type Fatal and injury, pinr PDO, ppnr pnr Fatal and injury, pinr PDO, ppnr pnr 4D Note: Locally-Derived Values provided courtesy of the Michigan Department of Transportation (MDOT). Chapter 11 Tables 8

10 HSM Chapter 11 Tables Table 11-22: Crash Modification Factors (CMF2i) for Installation of Left-Turn Lanes on Intersection Approaches Number of Non-Stop-Controlled Approaches with Left-turn Lanes a Intersection Type Crash Severity Level One Approach Two Approaches Three-leg minor-road stop Total control b Fatal and Injury Four-leg minor-road stop Total control b Fatal and Injury a Stop-controlled approaches are not considered in determining the number of approaches with left-turn lanes b Stop signs present on minor-road approaches only Table 11-23: Crash Modification Factors (CMF3i) for Installation of Right-Turn Lanes on Intersection Approaches Number of Non-Stop-Controlled Approaches with Right-turn Lanes a Intersection Type Crash Severity Level One Approach Two Approaches Three-leg minor-road stop Total control b Fatal and Injury Four-leg minor-road stop Total control b Fatal and Injury a Stop-controlled approaches are not considered in determining the number of approaches with right-turn lanes b Stop signs present on minor-road approaches only Table 11-24: Night-time Crash Proportions for Unlighted Intersections HSM-Provided Values Locally-Derived Values (Michigan) Proportion of total night-time crashes by severity level Proportion of crashes that occur at night Proportion of total night-time crashes by severity level Proportion of crashes that occur at night Roadway Type Fatal and injury, pini PDO, ppnr pni Fatal and injury, pinr PDO, ppnr pni 3ST ST Note: Locally-Derived Values provided courtesy of the Michigan Department of Transportation (MDOT). Notes for Tables 11-11, and for AADT see HSM. Chapter 11 Tables 9

11 HSM Chapter 12 Tables: HSM Default Tables Michigan Values Not Available Chapter 12 Tables: HSM Default Tables Michigan Values Not Available Table 12-3: SPF Coefficients for Multiple-Vehicle Non-driveway Collisions on Roadway Segments Coefficients use in Eqn Overdispersion Intercept AADT parameter (k) Road type (a) (b) Total crashes 2U T U D T Fatal-and-injury crashes 2U T U D T Property-damage-only crashes 2U T U D T Table 12-4: Distribution of Multiple-Vehicle Non-driveway Collisions for Roadway Segments by Manner of Collision Type Proportion of crashes by severity level for specific road types HSM-Provided Values 2U 3T 4U 4D 5T Collision type FI PDO FI PDO FI PDO FI PDO FI PDO Rear-end collision Head-on collision Angle collision Sideswipe, same direction Sideswipe, opposite direction Other multiple-vehicle collision Source: HSIS data for Washington ( ) Locally-Derived Values 2U 3T 4U 4D 5T Collision type FI PDO FI PDO FI PDO FI PDO FI PDO Rear-end collision Head-on collision Angle collision Sideswipe, same direction Sideswipe, opposite direction Other multiple-vehicle collision Note: HSM-Provided values based on HSIS data for Washington ( ) Chapter 12 Tables 10

12 HSM Chapter 12 Tables: HSM Default Tables Michigan Values Not Available Table 12-5: SPF Coefficients for Single-Vehicle Collisions on Roadway Segments Coefficients use in Eqn Overdispersion Intercept AADT parameter (k) Road type (a) (b) Total crashes 2U T U D T Fatal-and-injury crashes 2U T U D T Property-damage-only crashes 2U T U D T Table 12-6: Distribution of Single-Vehicle Collisions for Roadway Segments by Collision Type Proportion of crashes by severity level for specific road types HSM-Provided Values 2U 3T 4U 4D 5T Collision type FI PDO FI PDO FI PDO FI PDO FI PDO Collision with animal Collision with fixed object Collision with other object Other single-vehicle collision Source: HSIS data for Washington ( ) Locally-Derived Values 2U 3T 4U 4D 5T Collision type FI PDO FI PDO FI PDO FI PDO FI PDO Collision with animal Collision with fixed object Collision with other object Other single-vehicle collision Table 12-8: Pedestrian Crash Adjustment Factor for Roadway Segments Pedestrian Crash Adjustment Factor (fpedr) HSM-Provided Values Locally-Derived Values Road type Posted Speed 30 mph or Lower Posted Speed Greater than 30 mph Posted Speed 30 mph or Lower Posted Speed Greater than 30 mph 2U T U D T Note: These factors apply to the methodology for predicting total crashes (all severity levels combined). All pedestrian collisions resulting from this adjustment factor are treated as fatal-and-injury crashes and none as property-damage-only crashes. Source: HSIS data for Washington ( ) Chapter 12 Tables 11

13 HSM Chapter 12 Tables: HSM Default Tables Michigan Values Not Available Table 12-9: Bicycle Crash Adjustment Factor for Roadway Segments Bicycle Crash Adjustment Factor (fbiker) HSM-Provided Values Locally-Derived Values Road type Posted Speed 30 mph or Lower Posted Speed Greater than 30 mph Posted Speed 30 mph or Lower Posted Speed Greater than 30 mph 2U T U D T Note: These factors apply to the methodology for predicting total crashes (all severity levels combined). All pedestrian collisions resulting from this adjustment factor are treated as fatal-and-injury crashes and none as property-damage-only crashes. Source: HSIS data for Washington ( ) Table 12-10: SPF Coefficients for Multiple-Vehicle Collisions at Intersections Coefficients use in Eqn Overdispersion Intercept AADTmaj AADTmin parameter (k) Intersection type (a) (b) (c) Total crashes 3ST SG ST SG Fatal-and-injury crashes 3ST SG ST SG Property-damage-only crashes 3ST SG ST SG Table 12-11: Distribution of Multiple-Vehicle Collisions for Intersections by Collision Type Proportion of crashes by severity level for specific intersection types HSM-Provided Values 3ST 3SG 4ST 4SG Collision type FI PDO FI PDO FI PDO FI PDO Rear-end collision Head-on collision Angle collision Sideswipe Other multiple-vehicle collision Source: HSIS data for Washington ( ) Locally-Derived Values 3ST 3SG 4ST 4SG Collision type FI PDO FI PDO FI PDO FI PDO Rear-end collision Head-on collision Angle collision Sideswipe Other multiple-vehicle collision Note: HSM-Provided values based on HSIS data for California ( ) Chapter 12 Tables 12

14 HSM Chapter 12 Tables: HSM Default Tables Michigan Values Not Available Table 12-12: SPF Coefficients for Single-Vehicle Crashes at Intersections Coefficients use in Eqn Overdispersion Intercept AADTmaj AADTmin parameter (k) Intersection type (a) (b) (c) Total crashes 3ST SG ST SG Fatal-and-injury crashes 3ST SG ST SG Property-damage-only crashes 3ST SG ST SG Note: Where no models are available, the equation used is Nbisv(FI) = Nbisv(TOTAL) x fbisv Table 12-13: Distribution of Single-Vehicle Crashes for Intersections by Collision Type Proportion of crashes by severity level for specific intersection types HSM-Provided Values 3ST 3SG 4ST 4SG Collision type FI PDO FI PDO FI PDO FI PDO Collision with parked vehicle Collision with animal Collision with fixed object Collision with other object Other single-vehicle collision Noncollision Source: HSM-Provided values base on HSIS data for California ( ) Locally-Derived Values 3ST 3SG 4ST 4SG Collision type FI PDO FI PDO FI PDO FI PDO Collision with parked vehicle Collision with animal Collision with fixed object Collision with other object Other single-vehicle collision Noncollision Table 12-14: SPF for Vehicle-Pedestrian Collisions at Signalized Intersections Coefficients use in Eqn Overdispersion Intersection Intercept AADTtot AADTmin/AADTmaj PedVol nlanesx parameter (k) type (a) (b) (c) (d) (e) Total crashes 3SG SG Chapter 12 Tables 13

15 HSM Chapter 12 Tables: HSM Default Tables Michigan Values Not Available Table 12-15: Estimates of Pedestrian Crossing Volumes Based on General Level of Pedestrian Activity Estimate of PedVol (pedestrians/day) for Use in Equation General Level of Pedestrian Activity 3SG Intersections 4SG Intersections High 1, Medium-high Medium Medium-low Low Table 12-16: Pedestrian Crash Adjustment Factors for Stop-Controlled Intersections Intersection Type Pedestrian Crash Adjustment Factor (fpedi) 3ST ST Table 12-17: Bicycle Crash Adjustment Factors for Intersections Intersection Type Bicycle Crash Adjustment Factor (fbikei) 3ST SG ST SG Table 12-19: Values of fpk Used in Determining the CMF for On-Street Parking Type of Parking and Land Use Parallel Parking Angle Parking Road Type Residential/ Other Commercial or Industrial/ Institutional Residential/ Other Commercial or Industrial/ Institutional U T U D T Note: These factors apply to the methodology for predicting total crashes (all severity levels combined). All bicycle collisions resulting from this adjustment factor are treated as fatal-and-injury crashes and none as property-damage-only crashes. Source: HSIS data for Washington ( ) Table 12-22: CMFs for Median Widths on Divided Roadway Segments without a Median Barrier (CMF3r) Median Width (ft) CMF Chapter 12 Tables 14

16 HSM Chapter 12 Tables: HSM Default Tables Michigan Values Not Available Table 12-23: Nighttime Crash Proportions for Unlighted Roadway Segments HSM-Provided Values Proportion of Proportion of Total Nighttime Proportion of Total Nighttime Crashes that Crashes by Severity Level Crashes by Severity Level Occur at Night Road Type Fatal and Injury (pinr) PDO (ppnr) (pnr) 2U T U D T Fatal and Injury (pinr) Locally-Derived Values PDO (ppnr) Proportion of Crashes that Occur at Night (pnr) Table 12-24: Crash Modification Factor (CMF1i) for Installation of Left-Turn Lanes on Intersection Approaches Intersection Number of approaches with left-turn lanes Intersection traffic control Type One approach Two approaches Three approaches Four approaches 3ST Minor-road STOP control b SG Traffic signal ST Minor-road STOP control a SG Traffic signal a STOP-controlled approaches are not considered in determining the number of approaches with left-turn lanes. b Stop signs present on minor-road approaches only. Table 12-25: Crash Modification Factor (CMF2i) for Type of Left-Turn Signal Phasing Type of Left-Turn Signal Phasing CMF2i Permissive 1.00 Protected/permissive or permissive/protective 0.99 Protected 0.94 Note: Use CMF2i = 1.00 for all un-signalized intersections. If several approaches to a signalized intersection left-turn phasing, the values of CMF2i for each approach are multiplied together Table 12-26: Crash Modification Factor (CMF3i) for Installation of Right-Turn Lanes on Intersection Approaches Intersection Number of approaches with right-turn lanes Intersection traffic control Type One approach Two approaches Three approaches Four approaches 3ST Minor-road STOP control b SG Traffic signal ST Minor-road STOP control a SG Traffic signal a STOP-controlled approaches are not considered in determining the number of approaches with left-turn lanes. b Stop signs present on minor-road approaches only. Table 12-27: Nighttime Crash Proportions for Unlighted Intersections Proportion of crashes that occur at night, pni Intersection Type HSM-Provided Values Locally-Derived Values 3ST ST SG SG Chapter 12 Tables 15

17 HSM Chapter 12 Tables: HSM Default Tables Michigan Values Not Available Table 12-28: Crash Modification Factor (CMF1p) for the Presence of Bus Stops Near the Intersection Number of Bus Stops within 1,000 ft. of the Intersection CMF1p or or more 4.15 Table 12-29: Crash Modification Factor (CMF2p) for the Presence of Schools Near the Intersection Number of Schools within 1,000 ft. of the Intersection CMF2p No school present 1.00 School present 1.35 Table 12-30: Crash Modification Factor (CMF3p) for the Number of Alcohol Sales Establishment near the Intersection Number of Alcohol Sales Establishments within 1,000 ft. of the Intersection CMF3p or more 1.56 Chapter 12 Tables 16

18 HSM Module 3: Crash Modification Factors Sample Problem 3-1: Effectiveness of treatments on two-lane rural highway segment Brief Description of the Project/Case This analysis of a roadway segment involves County Road 63. The segment under review extends from CR 637 to CR 345. The roadway is a two-lane facility in a rural setting. Currently, the roadway segment consists of 12 lanes with 4 paved shoulders. What will be the likely change in expected run-off-the-road crashes and total crashes if the County narrows the lane widths to 11 and widens the shoulder widths to 5? The 2008 traffic count indicates that the average annual daily traffic (AADT) for the segment was 4,494 vehicles per day. Table 3-1 summarizes the crash history for the segment. Table 3-1. Crash History for Segment Year Run-off-the-road, headon, and sideswipe Total segment crashes crashes Total 33 (11.00 per year, 53.2% of total crashes) 62 (20.67 per year) Step 1. Calculate the existing CMF for 12 lanes Student Notes Sample Problem

19 HSM Module 3: Crash Modification Factors To adjust the lane width CMF for total crash assessment (based on proportion of crashes), use HSM Equation 13-3, p Run-off-the-road, Head-on, & Total Crashes Sideswipe Crashes CMF = 1.00 (per Table 13-2) CMF = ( ) x (per Equation 13-3) CMF = 1.00 Step 2. Calculate the CMF for proposed 11 lanes Run-off-the-road, Head-on, & Total Crashes Sideswipe Crashes CMF = 1.05 (per Table 13-2) CMF = ( ) x (per Equation 13-3) CMF = Step 3. Calculate the treatment corresponding to the change in lane width for runoff-the-road crashes and total crashes Run-off-the-road, Head-on, & Total Crashes Sideswipe Crashes CMF Treatment = = 1.05 CMF Treatment = = Step 4. Apply the treatment CMF to the expected number of crashes Run-off-the-road, Head-on, & Total Crashes Sideswipe Crashes For lane width CMFs - use Table 13-2, p of the HSM. The percentage of run-off-the-road, head-on, and sideswipe crashes is 53.2% per Table 3-1 of this sample problem. (If local crash type % values are unknown, HSM Table 10-6 provides defaults.) CMF Treatment = CMF 11 lane CMF 12 lane Where CMFfor 11 from Step 2 CMFfor 12 from Step 1 Use results from Step 3 and Table = crashes/year = crashes/year Step 5. Change in expected crashes due to proposed lane width changes Run-off-the-road, Head-on, & Total Crashes Sideswipe Crashes = 0.55 crashes/year (So an increase of 0.55 crashes/year) = 0.56 crashes/year (So an increase of 0.56 crashes/year) Use results from Step 4 and Table 3-1 Step 6. Calculate the existing CMF for 4 paved shoulders To adjust the paved shoulder width CMF for total crash assessment (based on proportion of crashes), use HSM Equation 13-3, p Run-off-the-road, Head-on, & Total Crashes Sideswipe Crashes CMF = 1.15 (per Table 13-7) CMF = ( ) x (per Equation 13-3) CMF = 1.08 For paved shoulder width CMFs - use Table 13-7, p of the HSM. The percentage of run-off-theroad, head-on, and sideswipe crashes is 53.2% per Table 3-1. Step 7. Calculate the CMF for proposed 5 paved shoulders and 4,494 vpd Sample Problem

20 HSM Module 3: Crash Modification Factors Run-off-the-road, Head-on, & Total Crashes Sideswipe Crashes CMF = (per Table 13-7) CMF = ( ) x (per Equation 13-3) CMF = 1.04 Step 8. Calculate the treatment corresponding to the change in shoulder width for run-off-the-road crashes and total crashes Run-off-the-road, Head-on, & Total Crashes Sideswipe Crashes CMF Treatment = = CMF Treatment = = Step 9. Apply the treatment CMF to the expected number of crashes Run-off-the-road, Head-on, & Sideswipe Crashes Total Crashes CMF Treatment = CMF 5 shld CMF 4 shld Where CMFfor 5 from Step 7 CMFfor 4 from Step 6 Use results from Step 8 and Table = crashes/year = crashes/year Step 10. Calculate the change in crashes due to proposed shoulder width changes. Run-off-the-road, Head-on, & Total Crashes Sideswipe Crashes = crashes/year (So a decrease of 0.71 crashes/year) = crashes/year (So a decrease of 0.76 crashes/year) Use results from Step 9 and Table 3-1 Step 11. Total change in expected crashes due to lane and shoulder width changes Run-off-the-road, Head-on, & Sideswipe Crashes Crashes = = (So an overall decrease of 0.16 crashes/year) = expected crashes following treatment Total Crashes Crashes = = (So an overall decrease of 0.20 crashes/year ) = expected crashes following treatment Use results from Step 5 and Step 10 SUMMARY The proposed changes will slightly decrease the run-off-the-road, head-on, and sideswipe crashes as well as total crashes. Sample Problem

21 HSM Module 4: Predictive Method Process Sample Problem 4-1: Design Exception Case Study Brief Description of the Project/Case The intersection of a four-lane undivided rural highway with minor road (STOP-controlled) currently does not have turn lanes and the lane width and shoulder width adhere to AASHTO policies. Student Notes As a possible way of improving safety at the intersection, an agency is considering narrowing the paved lane and shoulder widths so that they can maintain existing right-of-way widths and potentially add left and/or right turn-lanes on the mainline approaches. Using the predictive methodologies included in the HSM Vol. 2 (Part C) Chapter 11: Multilane Rural Highways, evaluate the impact of the proposed alternative designs on expected crash frequency for the year Step 1 Identify data needs for the facility Existing Road (study segment length of 0.38 miles): Mainline (major road) AADT of 30,000 vpd in 2009 (assume does not change at intersection) 66 cross-section (4 lanes + 2 shlds) [Lane Widths = 12, Paved Shlds = 8 ] Design Speed = 50 mph No lighting or automated speed enforcement No turn lanes and no intersection skew Roadside slope = 1:7 Intersecting Highway (minor road) AADT of 5,000 vpd in 2009 (assume does not change at intersection) Lane Widths = 11, No Shoulders (graded or paved) Design Speed = 50 mph Proposed Design A : Mainline (major road) changes Lane Widths reduced from 12 to 11 (does not meet policy and so requires an exception) Shoulder widths reduced from 8 to 6 (does not meet policy and so requires an exception) Add left-turn lanes in each direction (10 wide, 500 in length) Sample Problem

22 HSM Module 4: Predictive Method Process Proposed Design B : Mainline (major road) changes Lane Widths reduced from 12 to 10 (does not meet policy) Shoulder widths reduced from 8 to 3 (does not meet policy) Add left-turn lanes and right-turn-lanes in each direction (10 wide, 500 in length) Step 2 Divide locations into homogeneous segments or intersections For this study, all alternatives apply to one intersection location so this can be perceived as a single homogeneous segment site and a single homogeneous intersection site. Step 3 Apply the appropriate SPF It is appropriate to compute the SPF values for segments and intersections and then add them together. Since this location has modifications that directly influence lane and shoulder widths (safety influences captured during segment analysis), it is important to include this step. N predicted = N spf (CMF 1x CMF 2x CMF yx ) C x For all designs, the same SPF will be used but some of the CMF values will change due to the various proposed designs. Since this location is consistent for all candidate designs, the calibration factor will be the same for all designs. Predicted Segment Crashes for Base Conditions: Using Equation 11-7, the segment SPF for base conditions can be determined as follows: N spf segment [a+b ln(aadt)+ ln(l)] = e Sample Problem

23 HSM Module 4: Predictive Method Process The variables are defined from Table 11-3 for the various severity levels: N spf total segment crashes = e [ ln(30,000)+ ln(0.38)] = 4.49 Predicted Intersection Crashes for Base Conditions: Using Equation 11-11, the intersection SPF for base conditions can be determined as follows: N spf = e [a+b ln(aadt maj)+c ln(aadt min )] The variables are defined from Table 11-7 for the various severity levels: N spf total = e [ ln(30,000) ln(5,000)] = int crashes Sample Problem

24 HSM Module 4: Predictive Method Process Step 4 Apply CMFs as needed Segment Base Conditions (Undivided Roadway): Lane Width = 12 Shoulder Width = 6 Shoulder Type = Paved Side Slopes = 1V:7H or flatter No lighting or automated speed enforcement CMFs will be needed for any conditions that do not meet these base conditions, so for the proposed designs the lane width and shoulder width CMF values are required. Lane Width CMF (applicable for run-off-road, head-on, & sideswipe): So, LW=11 has CMF RA=1.04, LW=10 has CMF RA=1.23 (related crashes) CMF 1ru = (CMF RA 1. 0) p RA For 11 lanes: CMF 1ru = ( ) = Sample Problem

25 HSM Module 4: Predictive Method Process For 10 lanes: CMF 1ru = ( ) = Shoulder Width CMF (applicable for run-off-road, head-on, & sideswipe): So, SW=8 has CMF WRA=0.87, LW=3 has CMF WRA=1.225 (related crashes) Since the shoulder is paved, this will have a CMF TRA value of 1.00 for all cases. Apply Shoulder CMF values for each segment scenario: CMF 2ru = (CMF WRA CMF TRA 1. 0) p RA For 8 paved shoulders: CMF 2ru = ( ) = For 6 paved shoulders: CMF 2ru = ( ) = For 3 paved shoulders: CMF 2ru = ( ) = Sample Problem

26 HSM Module 4: Predictive Method Process Existing Conditions (12 lanes, 8 shoulders): N predicted = N spf (CMF 1ru CMF 2ru ) N predicted = 4.49 ( ) = 4.33 Proposed Design A (11 lanes, 6 shoulders): N predicted = 4.49 ( ) = 4.54 Proposed Design B (10 lanes, 3 shoulders): N predicted = 4.49 ( ) = 5.06 Intersection Base Conditions (4-Leg Minor STOP-controlled): Intersection Skew Angle of 0-degrees No left-turn or right-turn lanes (unless stop-controlled) No lighting CMFs will be needed for any conditions that do not meet these intersection base conditions, so for the proposed designs the addition of turn lanes require CMF adjustments. CMF values of 1.0 will be used for the skew and lighting CMF as these adhere to base conditions. Sample Problem

27 HSM Module 4: Predictive Method Process Left-turn Lane CMF: For left-turn lanes on two approaches (total crashes): CMF 2i = For no left-turn lanes: CMF 2i = Right-turn Lane CMF: For right-turn lanes on two approaches (total crashes): CMF 3i = For no right-turn lanes: CMF 3i = Sample Problem

28 HSM Module 4: Predictive Method Process To determine predicted crashes at intersections for each option: Existing Conditions (12 lanes, 8 shoulders): N adjusted = N spf (CMF 1i CMF 2i CMF 3i CMF 4i ) predicted N total int = ( ) = crashes adj Proposed Design A (add left-turn lanes, no right-turn lanes): N total int = ( ) = 6.66 crashes adj Proposed Design B (add left-turn lanes and right-turn lanes): N total int = ( ) = 4.93 crashes adj Combine Predicted Crashes for Segment and Intersections: Scenario Segment Crashes for 2009 Intersection Crashes for 2009 Total Predicted Crashes for 2009 Existing A B Step 5 Apply Local Calibration Factor For site-specific comparisons, the calibration factor is the same for all scenarios. If the goal is to simply determine which scenario would generate the lowest number of crashes (by comparison), then the calibration factor is not required here. If the goal is to more accurately the actual number of crashes for each scenario, then multiply each value obtained in Step 4 by the local calibration factor. For the two alternative scenarios, Proposed Design B with the narrower lanes and shoulders but left and right-turn lanes results in the fewest expected crashes at this location (9.71 for the year 2009). Acknowledgement: The original sample problem was developed by Michael Dimaiuta, Larry Sutherland, and Karen Dixon. Sample Problem

29 Module 7: Network Screening Case Study 7-1: Network Screening Vol. 1 (Part B) Case Study Brief Description of the Project/Case The following case study provides sample data for ten intersections with five-years of crash data ( ). A county is undertaking an effort to improve safety on their highway network and is screening ten intersections to identify sites with potential for reducing crashes depending on various criteria. The county will follow the HSM Roadway Safety Management Process beginning with Network Screening. Your first objective is to perform a network screening analysis for the 10 candidate intersections using the crash rate ranking, EPDO ranking, and expected crash frequency with EB adjustment network screening procedures. Group Discussion Questions: What are the strengths and/or weaknesses of each analysis procedure? Do the individual procedures provide dramatically different results? Which intersections should be the target for additional analysis? Case Study

30 Module 7: Network Screening Acquire data for the network screening of the selected intersections Available Data: For performing the network screening process, you will need crash data (crash type and crash severity) as well as traffic volume for the candidate intersections. Table 7-1. Sample Intersections Traffic Control and Entering Volumes Location Area Type & Traffic Intersection Major Route Minor Route Control Major Route ADT Minor Route ADT 1 Morris Blvd Chicago Ave Signalized 33,300 13, st Ave Golf Rd Signalized 34,800 17,500 3 Devon Ave Main St Signalized 27,800 18, rd St Park Ave Signalized 29,200 1,100 5 Wilson Rd Lake St Signalized 16,600 16,100 6 Kennedy Blvd Main St Signalized 33,300 13,200 7 Roosevelt Rd Lake St Signalized 20,300 17, th St Chicago Ave Signalized 30,800 18,500 9 Cicero Ave Banks Dr Signalized 37,500 17, Dawson Ave Howard St Signalized 13,100 12,700 Table 7-2. Sample Intersections Crash Severity ( ) Location Crashes by Severity Intersection Major Route Minor Route K A B C PDO 1 Morris Blvd Chicago Ave st Ave Golf Rd Devon Ave Main St rd St Park Ave Wilson Rd Lake St Kennedy Blvd Main St Roosevelt Rd Lake St th St Chicago Ave Cicero Ave Banks Dr Dawson Ave Howard St Case Study

31 Module 7: Network Screening Table 7-3. Sample Intersections Crash Type ( ) Intersection Location Major Route Minor Route Head-On and Opposite Direction Sideswipe Fixed Object and Overturned Angle and Turning Rear End and Same Direction Sideswipe Animal Pedestrian and Pedalcyclist Other Non- Collision and Other Object and Parked Car & Train 1 Morris Blvd Chicago Ave st Ave Golf Rd Devon Ave Main St rd St Park Ave Wilson Rd Lake St Kennedy Blvd Main St Roosevelt Rd Lake St th St Chicago Ave Cicero Ave Banks Dr Dawson Ave Howard St Table 7-4. Sample Intersections Light Condition Location Minor Day/ Intersection Major Route Route Daylight Dawn/ Dusk Light Condition Lighted Night/ Dark Unknown Total Total Crashes 1 Morris Blvd Chicago Ave st Ave Golf Rd Devon Ave Main St rd St Park Ave Wilson Rd Lake St Kennedy Blvd Main St Roosevelt Rd Lake St th St Chicago Ave Cicero Ave Banks Dr Dawson Ave Howard St Table 7-5. Sample Intersections Surface Condition Case Study

32 Module 7: Network Screening Location Intersection Major Route Minor Route Dry Wet Ice/Snow/Slush Other/ Unknown Total Crashes 1 Morris Blvd Chicago Ave st Ave Golf Rd Devon Ave Main St rd St Park Ave Wilson Rd Lake St Kennedy Blvd Main St Roosevelt Rd Lake St th St Chicago Ave Cicero Ave Banks Dr Dawson Ave Howard St Next Step: Next, perform network screening using the (1) crash rate ranking, (2) EPDO ranking, and (3) expected crash frequency with EB adjustment procedures. Case Study

33 Module 7: Network Screening Network Screening Method 1: Step 1: Calculate Million Entering Vehicles (MEV): Performance Measure 1: Crash Rate Ranking MEV = (TEV/1,000,000) x (n) x (365) Reference: Equation 4-2, p of HSM Where: TEV = Total entering vehicles per day, n = Number of years of crash data Step 2: Calculate Crash Rate: Crash Rate (R ) = N observed i(total) / MEV i Reference: Equation 4-3, p of HSM For Intersection 1: MEV = (( )/1,000,000) x 5 x 365 = R = 257/84.86 = 3.03 Step 3: Rank Locations: Intersection Total Crashes MEV Crash Rate (CR) Rank Case Study

34 Module 7: Network Screening Network Screening Method 2: Performance Measure 2: EPDO - Ranking Step 1: Calculate EPDO Weights: f y = CC y/cc PDO Reference: Equation 4-4 (p.4-30 HSM) EPDO Weight (Injury Crash) = $82,600/$7,400 = EPDO Weight (Fatal Crash) = $4,008,900/$7,400 = (Every Injury Crash is equivalent to PDO Crash) (Every Fatal Crash is equivalent to PDO Crash) Severity Comprehensive Cost (2001 Dollars) Equivalent Weights (Refer to Table 4-7 on p.4-29) Fatal (K) $4,008, Injury Crashes (A/B/C) $82, PDO $7,400 1 Step 2: Calculate EPDO Score: Total EPDO Score = (Total Fatal Crashes) (Total Injury Crashes) + 1 (Total PDO Crashes) For Intersection 1 - EPDO Score = ( x 0) + (11.16 x 63) + (1 x 194) = 897 Step 3: Rank Sites: Intersection EPDO Score Rank Case Study

35 Module 7: Network Screening Network Screening Method 3: Performance Measure 3: Expected Crash Frequency with Empirical Bayesian (EB) Adjustment Intersection Ranking with expected average crash frequency using EB adjustment TOTAL crashes Fatal and Injury Crashes (KABC) PDO crashes (O) Intersection Intersection Intersection Intersection Intersection Intersection Intersection Intersection Intersection Intersection Summary of Network Screen Assessment: Based on the crash rate ranking, EPDO ranking, and the expected crash frequency with EB adjustment we see that Intersections 2, 6, and 8 are all ranked as the top three locations where there is the most opportunity for crash reduction. Though the ranking between first and second varies between Intersections 2 and 8, this network screen assessment can confirm that each of these three intersections merit additional diagnosis and evaluation. Acknowledgements: The original case study was developed by Darren Torbic and Ingrid Potts from MRI. Case Study

36 Module 9: Diagnosis and Countermeasure Selection Case Study 9-1: Diagnosis and Countermeasure Selection Vol. 1 (Part B) Case Study Brief Description of the Project/Case As introduced in Module #7, Case Study 7-1, one continuous sample problem has been developed to demonstrate the entire roadway safety management process. Case Study 7-1 identified three candidate intersection locations that require additional analysis to see if there are opportunities to reduce crashes at these locations. One of the intersections that ranked highly by all three of the demonstrated network screening evaluations was Intersection 2 (1 st Avenue and Golf Road). In this portion of the case study, the agency has now elected to focus on Intersection 2, diagnose the intersection, and then identify candidate countermeasures for this location. In addition to a site visit and general review of the crash history at this location, the analyst can calculate the predicted average number of crashes at the intersection and then evaluate two countermeasures that have been recommended by their staff. The two candidate countermeasures include (1) changing the intersection to a roundabout, and keeping the intersection and adding a protected left-turn traffic signal phase. An aerial photo of the intersection location is shown below: Case Study