Exercise I – Prediction of Safety Performance for Rural Multilane Highway and Comparison to Substantive Safety Performance - Session #4 HSM Applications to Multilane Rural Highways and Urban Suburban Streets 4-1

Exercise I – IL 64 North Avenue from Bloomingdale Road to Main Street-Glen Ellyn Learning Outcomes: ► Apply Rural Multilane Crash Prediction model ►Calculate Severity Rate ►Compare predicted safety performance to actual safety performance 4-2

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. Exercise I – IL 64 North Avenue from Bloomingdale Road to Main Street-Glen Ellyn 4-3

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Geometric Information: Cross-Section: Four 12-foot wide lanes with double yellow centerline dividing the opposing directions of travel (Undivided) 8 foot wide Gravel shoulders 12 foot wide left turn lanes at all major intersections No left turn lanes at minor street intersections nor at commercial driveways No highway illumination other than some minor intersection lighting by local municipalities and the County Highway Department; no automated speed enforcement Exercise I – IL 64 North Avenue from Bloomingdale Road to Main Street-Glen Ellyn 4-5

Study Section: Length of Section = 0.97 miles AADT= 37,000 vpd No Horizontal Curves side slope = 1:6 Trees and Power poles 18.0 feet from edge of pavement Exercise I – IL 64 North Avenue from Bloomingdale Road to Main Street-Glen Ellyn 4-6

Study Section: Number of Unsignalized Intersections with left turn lanes 0 Number of Unsignalized Intersections without turn lanes 9 Exercise I – IL 64 North Avenue from Bloomingdale Road to Main Street-Glen Ellyn 4-7 Driveways: Residential driveways 7 Minor commercial driveways (< 50 parking spaces) 7 Major commercial driveways (> 50 parking spaces)11 Total # of Driveways25

Unsignalized T- Intersections: Mildred 700 AADT Virginia 700 AADT Bernice 700 AADT Western 700 AADT Pearl 1,500 AADT Diane 700 AADT Evergreen 700 AADT Amy 700 AADT Newton 700 AADT Signalized 4-Approach Intersections: Bloomingdale Road16,100 AADT Shopping Center (north and south) 2,400 AADT Main Street-Glen Ellyn16,700 AADT Exercise I – IL 64 North Avenue from Bloomingdale Road to Main Street-Glen Ellyn

Study Section: Total Injury CrashesCrashesDay Night Rdwy Segment SubTotal: Crash data for 1986, 1987, 1988 – 3 years Exercise I – IL 64 North Avenue from Bloomingdale Road to Main Street-Glen Ellyn 4-9

Intersections:Total Injury DayNight Mildred Virginia Bernice Western Pearl Diane Evergreen Amy Newton Bloomingdale Rd Shopping Center Main St-Glen Ellyn Totals: Crash data for 1986, 1987, 1988 – 3 years 4-10

Study Section: Total Injury CrashesCrashesDay Night Rdwy Segment Intersections Totals: Crash data for 1986, 1987, 1988 – 3 years Exercise I – IL 64 North Avenue from Bloomingdale Road to Main Street-Glen Ellyn 4-11

1.Predict the Crash Performance for the segment using the Rural Undivided Multilane model for the following: a.Base Model for the Roadway Segment b.CMFs for; Lane Width, Shoulder Width and type, Side Slope, Lighting, and Automated Speed Enforcement c.Total Predicted Crashes for Segment (with CMF’s applied) Exercise I – IL 64 North Avenue from Bloomingdale Road to Main Street-Glen Ellyn 4-12

From the crash information, perform the following: 2.Compute the Severity Index (SI) for the segment and for the 3 signalized intersections SI segment = Fatal + Injury Crashes Total Crashes Is the Severity Index higher or lower than normal? Exercise I – IL 64 North Avenue from Bloomingdale Road to Main Street-Glen Ellyn 4-13

From the Crash Prediction analysis, answer the following question: 3.Is the actual Crash Frequency of the geometrics for IL 64 (Lane Width, Shoulder Width and Type, Sideslope, Lighting and Automated Spd Enf) less than the predicted Crash Frequency? ? crashes per year Actual Safety Performance = Predicted Segment Crashes = = ? crashes per year Yes or No? Exercise I – IL 64 North Avenue from Bloomingdale Road to Main Street-Glen Ellyn 4-14 Use Worksheet 1

1.Predict the Crash Frequency Performance for the segment using the Rural Undivided Multilane model for the following: a.Base Model for the Roadway Segment b.CMFs for; Lane Width, Shoulder Width and type, Side Slope, Lighting, and Automated Speed Enforcement c.Total Predicted Crashes for Segment (with CMF’s applied) Exercise I – IL 64 North Avenue from Bloomingdale Road to Main Street-Glen Ellyn 4-15

1.Predict the Crash Frequency Performance for the segment using the Rural Undivided Multilane model for the following: a.Base Model for the segment N spf ru = e (a + b Ln AADT + Ln L) = e ( Ln Ln 0.97) = e (2.6865) = crashes per year Exercise I – IL 64 North Avenue from Bloomingdale Road to Main Street-Glen Ellyn 4-16

1.Predict the Crash Frequency Performance for the segment using the Rural Undivided Multilane model for the following: b.CMF for Lane Width: 12’ CMF 1ru = (1.00-1) x = 1.00 Exercise I – IL 64 North Avenue from Bloomingdale Road to Main Street-Glen Ellyn 4-17

1.Predict the Crash Frequency Performance for the segment using the Rural Undivided Multilane model for the following: b.CMF for Shoulder Width: 8’ CMF wra =0.87 Exercise I – IL 64 North Avenue from Bloomingdale Road to Main Street-Glen Ellyn 4-18

1.Predict the Crash Frequency Performance for the segment using the Rural Undivided Multilane model for the following: b.CMF for Shoulder Type: 8’ aggregate CMF tra =1.02 Exercise I – IL 64 North Avenue from Bloomingdale Road to Main Street-Glen Ellyn 4-19

1.Predict the Crash Frequency Performance for the segment using the Rural Undivided Multilane model for the following: CMF 2ru = (CMF wra x CMF tra – 1.0) = 0.97 = (0.87 x ) b.CMF 2ru for Shoulder Width & Type: 8’ aggregate Exercise I – IL 64 North Avenue from Bloomingdale Road to Main Street-Glen Ellyn 4-20

1.Predict the Crash Frequency Performance for the segment using the Rural Undivided Multilane model for the following: b.CMF for Side Slope: 1:6 CMF 3ru =1.05 Exercise I – IL 64 North Avenue from Bloomingdale Road to Main Street-Glen Ellyn 4-21

1.Predict the Crash Frequency Performance for the segment using the Rural Undivided Multilane model for the following: b.CMF for Lighting : none CMF 4ru = 1.0 CMF 4ru = 1 – [(1– 0.72P inr – 0.83P pnr )P nr ] Exercise I – IL 64 North Avenue from Bloomingdale Road to Main Street-Glen Ellyn 4-22

1.Predict the Crash Frequency Performance for the segment using the Rural Undivided Multilane model for the following: b.CMF for Automated Speed Enforcement: none CMF 5ru = 1.0 Exercise I – IL 64 North Avenue from Bloomingdale Road to Main Street-Glen Ellyn 4-23

1.Predict the Crash Frequency Performance for the segment using the Rural Undivided Multilane model for the following: c.Predicted Crashes with CMF’s applied N ru = N spf ru x CMF 1ru x CMF 2ru x CMF 3ru x CMF 4ru x CMF 5ru = x 1.00 x x 1.05 x 1.00 x 1.00 = 14.9 crashes per year Exercise I – IL 64 North Avenue from Bloomingdale Road to Main Street-Glen Ellyn 4-24

From the crash information, perform the following: 2.Compute the Severity Index (SI) for the segment (Substantive and Predicted) SI segment = Fatal + Injury Crashes Total Crashes Is the Substantive Severity Index higher or lower than the Predicted Severity Index? Exercise I – IL 64 North Avenue from Bloomingdale Road to Main Street-Glen Ellyn 4-25

Severity Index for all highways and streets Severity index (SI) is the ratio of crashes involving an injury or fatality to total crashes 4-26 ►..however, for multilane rural highways, injury and fatal crash frequency SPF coefficients are available in Chapter 11, Table 11-3…..…..

2.Compute the Predicted Severity Index (SI) for the undivided highway segment: Exercise I – IL 64 North Avenue from Bloomingdale Road to Main Street-Glen Ellyn N spf ru = e (a + b Ln AADT + Ln L) = e ( Ln 37,000 + Ln 0.97) = 7.9 injury and fatal crashes per year 4-27

2.Compute the Predicted Severity Index (SI) for the segment: Exercise I – IL 64 North Avenue from Bloomingdale Road to Main Street-Glen Ellyn N spu-ru = 7.9 injury and fatal crashes/yr N spu-ru = total crashes/yr from #1 SI segment = Fatal + Injury Crashes Total Crashes = 7.9 injury + fatal crashes/yr total crashes/yr = 0.53 predicted severity index 4-28

From the crash information, perform the following: 2.Compute the Severity Index (SI) for the segment (Substantive and Predicted): Substantive SI segment = Fatal + Injury Crashes = 26 = 31% Total Segment Crashes 84 Exercise I – IL 64 North Avenue from Bloomingdale Road to Main Street-Glen Ellyn 4-29 ►Substantive Severity Index is lower than Predicted severity Index Predicted SI segment = 53%

From the Crash Prediction analysis, answer the following question: 3.Is the actual Crash Frequency Performance of the geometrics for IL 64 (Lane Width, Shoulder Width and Type, Sideslope, Lighting and Auto Spd Enf) less than the predicted value? Actual Safety Performance = Predicted Segment Crashes = = 14.9 crashes per year No! 2 x’s > predicted Exercise I – IL 64 North Avenue from Bloomingdale Road to Main Street-Glen Ellyn /3 = 28 crashes per year

Exercise I – IL 64 North Avenue from Bloomingdale Road to Main Street-Glen Ellyn Learning Outcomes: ► Calculated Severity Rate ►Applied Rural Multilane Crash Prediction model ►Compared predicted safety performance to actual safety performance 4-31

Questions and Discussion Exercise I – IL 64 North Avenue from Bloomingdale Road to Main Street-Glen Ellyn 4-32