GROUP EXERCISE “III” Prediction of Crash Frequency Performance for Multilane Rural Intersections and Comparison to Substantive Safety Performance
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.
Study Section: Bloomingdale Road to Main Street-Glen Ellyn Length of Section = 0.97 miles AADT = 37,000 vpd
Three Signalized intersections with single left turn lanes (no right turn lanes): Bloomingdale Road 16,100 AADT Shopping Center (north and south) 2,400 AADT Main Street-Glen Ellyn 16,700 AADT
Unsignalized T-Intersections w/o left turn lanes – stop control of minor street approach: 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 Intersections 4 approaches with single left turn lanes on all four approaches: Bloomingdale Road 16,100 AADT Shopping Center (north and south) 2,400 AADT Main Street-Glen Ellyn 16,700 AADT
Exercise IV – Prediction of Intersection Crashes for IL 64-North Avenue as a Rural Multilane 1 Highway Substantive Safety Performance: 3-years crash data 1986, 1987, 1988
Total Injury Crashes Crashes Day Night Rdwy Segment 84 26 57 27
Intersections: Total Injury Day Night Crashes Crashes Mildred 9 2 6 3 Virginia 12 3 9 3 Bernice 16 3 11 5 Western 11 4 7 4 Pearl 22 6 16 6 Diane 16 5 11 5 Evergreen 11 4 7 4 Amy 7 4 4 3 Newton 12 5 8 4 Bloomingdale Rd 170 68 122 48 Shopping Center 18 5 13 5 Main St-Glen Ellyn 146 45 100 46 Sub Total: 450 154 314 136 Total Segment + Intersections: 534 180 371 163
1. Predict the Crash Performance for the intersections using the Rural Multilane intersection models for the following: a. Bloomingdale Road (signalized) b. Shopping Center (signalized) c. Main Street-Glen Ellyn (signalized) d. Eight “T” non-signalized intersections (700 AADT) e. One “T” non-signalized intersection (1,500 AADT)
a. Bloomingdale Road (signalized) (See Table 11-8)
Nrural = exp(a + b ln(AADTMajor) + c ln(AADTMinor)
= exp(-7.182 + 0.722ln(37,000) + 0.337ln(16,100)
= exp( -7.182 + 7.594 + 3.264 )
Exercise IV – Prediction of Intersection Crashes3.676 for IL 64-North Avenue as a Rural Multilane 2 Highway = exp( )
= 39.5 crashes per year
b. Shopping Center (signalized)
Nrural = exp(a + b ln(AADTMajor) + c ln(AADTMinor)
= exp(-7.182 + 0.722ln(37,000) + 0.337ln(2,400)
= exp( -7.182 + 7.594 + 2.623 )
= exp( 3.035 )
= 20.8 crashes per year c. Main Street-Glen Ellyn (signalized)
Nrural = exp(a + b ln(AADTMajor) + c ln(AADTMinor)
= exp(-7.182 + 0.722ln(37,000) + 0.337ln(16,700)
= exp( -7.182 + 7.594 + 3.277 )
= exp( 3.689 )
= 40.0 crashes per year
d. Eight “T” stop control of approach at 700 AADT (See Table 11-7)
Nrural = exp(a + b ln(AADTMajor) + c ln(AADTMinor) Exercise IV – Prediction of Intersection Crashes for IL 64-North Avenue as a Rural Multilane 3 Highway = exp(-12.526 + 1.204ln(37,000) + 0.236ln(700)
= exp( -12.526 + 12.664 + 1.546 )
= exp( 1.684 )
= 5.39 crashes per year
= 8 x 5.39 crashes per year
= 43.12 crashes per year
e. One “T” stop control of approach at 1500 AADT
Nrural = exp(a + b ln(AADTMajor) + c ln(AADTMinor)
= exp(-12.526 + 1.204ln(37,000) + 0.236ln(1,500)
= exp( -12.526 + 12.664 + 1.726 )
= exp( 1.864 )
= 6.5 crashes per year
Exercise IV – Prediction of Intersection Crashes for IL 64-North Avenue as a Rural Multilane 4 Highway 2. Predict the Crash Performance for the intersections using the Rural Multilane intersection models for the following:
a. Bloomingdale Road (signalized) 39.5
b. Shopping Center (signalized) 20.8
c. Main Street-Glen Ellyn (signalized) 40.0
43.1 d. Eight “T” non-signalized intersections (700 ADT)
e. One “T” non-signalized intersection (1,500 ADT) 6.4
Total Predicted Intersection Crashes 149.9
3. Compare the Substantive Intersection Safety Performance to the Predicted Crash Frequency Performance
Substantive Safety Performance = 450 crashes in 3 years
= 150 crashes per year
Predicted Intersection Crashes 149.9 crashes per year Frequency per year =
Substantive Safety Performance less About Same Than Predicted Crash Frequenecy ?
Exercise IV – Prediction of Intersection Crashes for IL 64-North Avenue as a Rural Multilane 5 Highway