1. HSM Applications to Multilane Rural Highways and Urban Suburban Streets
Safety and Operational Effects of Geometric Design Features for Two-Lane Rural Highways Workshop
April 2009
Exercise II – Prediction of Safety Performance for Urban/Suburban Multilane Highway and Comparison to Substantive
Safety Performance
- Session #6
Instructor: Session #6– Exercise II –– Prediction of Safety Peformance for suburban/urban Multilane Highway and Comparison to Substantive Safety Performance
Photo is IL 64 case study in “before” condition of 4lanes with double yellow separating the opposing traffic lanes and 8 foot gravel shoulders
Session 5 –Exercise I

2. Apply Urban/Suburban Multilane Crash Prediction model
Exercise II – IL 64 North Avenue from Bloomingdale Road to Main Street-Glen Ellyn
Safety and Operational Effects of Geometric Design Features for Two-Lane Rural Highways Workshop
April 2009
Learning Outcomes:
Apply Urban/Suburban Multilane Crash Prediction model
Compare predicted safety performance to actual safety performance
Instructor:
Please review the Learning Objectives for Session #07 Exercise II
Session 5 –Exercise I

3. Safety and Operational Effects of Geometric Design Features for Two-Lane Rural Highways Workshop
April 2009
Exercise II – IL 64 North Ave from Bloomingdale Rd to Main St – Glen Ellyn
IL 64, DuPage County, Illinois:
IL Route 64, an east-west state highway initiates at Lake Michigan in the City of Chicago and terminates at the Mississippi River at the west border of Illinois. In DuPage County, 1987 population of 780,000, IL Route 64 is known as North Avenue traversing the cities of Elmhurst and Villa Park and through rural unincorporated areas west to St. Charles Illinois in Kane County. IL Route 64 was improved to 4 lanes in the 1960’s throughout this length with intersection improvements at major crossroads such as other state routes and county routes consisting of left turn lanes and traffic signal control during the 1960’s and 1970’s.
Instructor: IL 64 Geometric Plan information
Session 5 –Exercise I

4. Safety and Operational Effects of Geometric Design Features for Two-Lane Rural Highways Workshop
April 2009
Instructor: IL 64 location map
Session 5 –Exercise I

5. Safety and Operational Effects of Geometric Design Features for Two-Lane Rural Highways Workshop
April 2009
Exercise II – IL 64 North Ave from Bloomingdale Rd to Main St – Glen Ellyn
Geometric Information:
Cross-Section:
Four 12-foot wide lanes with double yellow centerline dividing the opposing directions of travel (Undivided)
8 foot wide aggregate shoulders
12 foot wide left turn lanes at all major intersections
No left turn lanes at minor street intersections nor at commercial driveways
Parking prohibited
No highway illumination other than some minor intersection lighting by local municipalities and the County Highway Department
Instructor: IL 64 Geometric Plan information
Session 5 –Exercise I

6. Safety and Operational Effects of Geometric Design Features for Two-Lane Rural Highways Workshop
April 2009
Exercise II – IL 64 North Ave from Bloomingdale Rd to Main St – Glen Ellyn
Study Section:
Length of Section = 0.97 miles
ADT = 37,000 vpd
No Horizontal Curves; 2.8% vertical curve west of Shopping Center for 0.35 mi
Driveways:
Minor Residential driveways 7
Minor commercial driveways (< 50 parking spaces) 7
Major commercial driveways (> 50 parking spaces) 11
Total # of Driveways
Instructor: Let’s keep the data the same as in Slide  Please note that one additional major driveway has been added to the driveway total – a new shared driveway to a McDonalds and a Portiollo’s and the Portiollo’s traffic is nearly double that of the McDonalds.
Session 5 –Exercise I

7. Safety and Operational Effects of Geometric Design Features for Two-Lane Rural Highways Workshop
April 2009
Exercise II – IL 64 North Ave from Bloomingdale Rd to Main St – Glen Ellyn
Study Section:
Number of Unsignalized Intersections with left turn lanes 0
Number of Unsignalized Intersections without turn lanes 9
Trees and Power poles 18.0 feet from edge of pavement with spacing of 160 foot apart, one side
Signalized Intersections:
Bloomingdale Road 16,100 AADT
Shopping Center (north and south) 2,400 AADT
Main Street-Glen Ellyn 16,700 AADT
Instructor: IL 64 Geometric Plan information
Session 5 –Exercise I

8. Safety and Operational Effects of Geometric Design Features for Two-Lane Rural Highways Workshop
April 2009
Exercise II – IL 64 North Ave from Bloomingdale Rd to Main St – Glen Ellyn
Unsignalized Intersections:
Mildred AADT
Virginia AADT
Bernice AADT
Western AADT
Pearl ,500 AADT
Diane AADT
Evergreen AADT
Amy AADT
Newton AADT
Signalized Intersections:
Bloomingdale Road 16,100 AADT
Shopping Center (north and south) 2,400 AADT
Main Street-Glen Ellyn 16,700 AADT
Instructor: North Avenue IL 64 intersection information for the mile segment from Bloomingdale Road on the west to Glen Ellyn Road on the east
Session 5 –Exercise I

9. Safety and Operational Effects of Geometric Design Features for Two-Lane Rural Highways Workshop
April 2009
Exercise II – IL 64 North Ave from Bloomingdale Rd to Main St – Glen Ellyn
Study Section:
Crash data for 1986, 1987, 1988 – 3 years
Total Injury
Crashes Crashes Day Night
Rdwy Segment
SubTotal:
Instructor: “Before” crash data from IDOT Safety Section from the Phase I study for North Avenue IL 64 project
Session 5 –Exercise I

10. Safety and Operational Effects of Geometric Design Features for Two-Lane Rural Highways Workshop
April 2009
Crash data for 1986, 1987, 1988 – 3 years
Intersections: Total Injury Day Night
Mildred
Virginia
Bernice
Western
Pearl
Diane
Evergreen
Amy
Newton
Bloomingdale Rd
Shopping Center
Main St-Glen Ellyn
Totals:
Instructor: “Before” crash data from IDOT Safety Section from the Phase I study for North Avenue IL 64 project
Total Crashes for the 12 intersections = 450 crashes
Injury Crashes for the 12 intersections = 154 crashes
Session 5 –Exercise I

11. Safety and Operational Effects of Geometric Design Features for Two-Lane Rural Highways Workshop
April 2009
Exercise II – IL 64 North Ave from Bloomingdale Rd to Main St – Glen Ellyn
Study Section:
Crash data for 1986, 1987, 1988 – 3 years
Total Injury
Crashes Crashes Day Night
Rdwy Segment
12 Intersections
Totals:
Instructor: “Before” crash data from IDOT Safety Section from the Phase I study for North Avenue IL 64 project
Session 5 –Exercise I

12. Safety and Operational Effects of Geometric Design Features for Two-Lane Rural Highways Workshop
April 2009
Exercise II – IL 64 North Ave from Bloomingdale Rd to Main St – Glen Ellyn
Predict the Crash Frequency Performance for the segment using the Suburban Multilane Undivided model (4U) for the following:
Base Model Multiple Vehicle Non-Driveway
Base Model Single Vehicle Non-Driveway
Driveway Related Crashes
CMF’s for Parking, Roadside Objects, and Lighting
Predicted Crashes with CMF’s Applied
Pedestrian Crashes
Bicycle Crashes
Total Predicted Crashes for Segment
Instructor: go thru Task #1 and the eight (8) sub tasks – subtask a through h - in Task 1
Session 5 –Exercise I

13. Safety and Operational Effects of Geometric Design Features for Two-Lane Rural Highways Workshop
April 2009
Exercise II – IL 64 North Ave from Bloomingdale Rd to Main St – Glen Ellyn
From the Crash Frequency Prediction analysis, perform the following:
Is the actual Crash Frequency Performance for the geometrics for IL 64 less than the Predicted Crash Frequency Performance?
Instructor: go thru task 2
And the crucial aspect is the substantive safety performance (actual crashes per year) safer than the predicted number of crashes or not; if not, then the safety performance needs improvement
Instructor should hold on this slide while the workshop participants do tasks 1 and 2 – should take about 20 minutes
Substantive Safety Performance = ?
Predicted Safety Performance = ?
Safer than Predicted
YES/NO?
Session 5 –Exercise I

14. Nrs = (Nbr + Npedr + Nbiker) Cr
Safety and Operational Effects of Geometric Design Features for Two-Lane Rural Highways Workshop
April 2009
Exercise II – IL 64 North Ave from Bloomingdale Rd to Main St – Glen Ellyn
Procedure for safety prediction for a roadway segment: Combine base models, CMFs, and calibration factor
Nrs = (Nbr + Npedr + Nbiker) Cr
Nbr = Nspf rs (CMF1r x CMF2r x … CMFnr)
Instructor: from Chapter 12 of the Draft Highway Safety Manual on Roadway Segments.
Remind participants of the prediction models and associated variables.
Nspf rs = Nbrmv + Nbrsv + Nbrdwy
Use Worksheet Exercise II
Session 5 –Exercise I

15. Nbr = Nspf rs(CMF1r x CMF2r x .. CMFnr)
Safety and Operational Effects of Geometric Design Features for Two-Lane Rural Highways Workshop
April 2009
Exercise II – IL 64 North Ave from Bloomingdale Rd to Main St – Glen Ellyn
Nbr = Nspf rs(CMF1r x CMF2r x .. CMFnr)
Where:
Nbr = Predicted number of total roadway segment crashes per year with CMFs applied
Nspf rs = Nbrmv + Nbrsv + Nbrdwy = 19.2 crashes/yr
CMF’s = Crash Modification Factors for roadway segments (Parking, Roadside Objects, and Lighting)
Instructor: from Chapter 12 of the Draft Highway Safety Manual
Now that we’ve calculated Nspf rs we can move on and calculate Nbr which appllies the CMFs to the predicted crash frequency for base conditions.
Session 5 –Exercise I

16. Safety and Operational Effects of Geometric Design Features for Two-Lane Rural Highways Workshop
April 2009
Exercise II – IL 64 North Ave from Bloomingdale Rd to Main St – Glen Ellyn
From the Crash Frequency Prediction analysis, perform the following:
Is the actual Crash Frequency performance for the geometrics for IL 64 (Driveways, parking, and lighting) less than the Predicted Crash Frequency?
Substantive Safety Performance =
Instructor: and the answer to “safer than predicted is…..” NO, it is not safer and it is not safer by a factor greater than 3
Please keep in mind that the crashes for the 9 side roads are included in the before segment crashes
____crashes per year
Predicted Crash Frequency =
____ crashes per year
Less than Predicted ?
YES/NO
Session 5 –Exercise I

17. Applied Rural Multilane Crash Prediction model
Safety and Operational Effects of Geometric Design Features for Two-Lane Rural Highways Workshop
April 2009
Exercise II – IL 64 North Ave from Bloomingdale Rd to Main St – Glen Ellyn
Learning Outcomes:
Applied Rural Multilane Crash Prediction model
Compared predicted safety performance to actual safety performance
Instructor: please review Learning Objectives for Session #7 – Exercise II
Session 5 –Exercise I

18. Questions and Discussion
Safety and Operational Effects of Geometric Design Features for Two-Lane Rural Highways Workshop
April 2009
Questions and Discussion
Session 5 –Exercise I