Transcript Slide 1
Week 8, CE 552 - Typical crash rates and distributions - Crashes that take the highest toll on human life Why analyze crash data? • Identify patterns • Determine causes • Develop countermeasures Rates …why? • To compare locations • To decide if a location is at abnormal risk • Rate per million entering vehicles: This should really be RHMVM, shouldn’t it? Expected value analysis • Use only to compare “similar” sites (geometry, control, volume) • Problem: crashes are non-neg. count data (normal distribution does not apply) Cluster analysis • E.g., if a site has one right-angle, two rear-end and 6 left-turn crashes, one might say the leftturn crashes represent a cluster • But … what if the # of left turns is very high … then, is 6 high? • Need exposure data • Must usually use good engineering judgment Summarizing crash data Type Severity, e.g., KABCO, MAIS Time Periods a) b) c) Contributing Circumstances Hour Day Month Environmental Conditions a) light condition b) surface condition Typical crash rates Iowa data for risk by road type Oregon crash rates (compare to Iowa) Source: NCHRP Web Only Document 126 Guidelines for using NC crash rates Crash rate discussion Aussie rates – compare road types European crash rates by road type Low traffic flow roads – there are significant differences in fatal and serious accident rate between roads with less than 10,000 Average Annual Daily Traffic (AADT), roads with 10,000 to 20,000 AADT, and roads with more than 20,000 AADT. (The ratio of these differences is about 2.3:1.8:1); Note: to convert /bvkm to /HMVM, multiply by ~6 (Iowa K+A+B crash rate per HMVM in ~60, much lower than the numbers presented above for Europe if you multiply them by 6) http://www.eurorap.org/library/pdfs/roaddesignfactors.pdf Kentucky Intersection Crash Rates http://www.ktc.uky.edu/Reports/KTC_03_21_SPR258_03_2I.pdf Massachusetts Intersection Crash Rates From Oregon Study … http://www.oregon.gov/ODOT/HWY/TRAFFIC-ROADWAY/docs/pdf/safety_of_4-leg_vs_T.pdf http://www.oregon.gov/ODOT/HWY/TRAFFIC-ROADWAY/docs/pdf/safety_of_4-leg_vs_T.pdf http://www.oregon.gov/ODOT/HWY/TRAFFIC-ROADWAY/docs/pdf/safety_of_4-leg_vs_T.pdf http://www.oregon.gov/ODOT/HWY/TRAFFIC-ROADWAY/docs/pdf/safety_of_4-leg_vs_T.pdf Crashes that take the highest toll on human life • Head-ons, Intersections, ROR, VRU • Show iRAP video http://www.eurorap.org/library/pdfs/roaddesignfactors.pdf Head-on collisions • In this video, the ADAC Strassentest Car barely escapes a head-on crash. • Fatal Head On Accident Six Killed On US12 Near Morton WA • Truck crossing median – 7 fatals video http://onlinepubs.trb.org/onlinepubs/nchrp/nchrp_rpt_500v20.pdf Intersections (junctions) See: UMN captured crashes http://onlinepubs.trb.org/Onlinepubs/nchrp/nchrp_rpt_500v5.pdf Manner of collision Run-off the road (ROR) http://www.t2.unh.edu/nltapa/Pubs/fhwa's_roadway_departure_program.pdf http://www.t2.unh.edu/nltapa/Pubs/PLD-1.pdf http://onlinepubs.trb.org/Onlinep ubs/nchrp/nchrp_rpt_500v6.pdf http://www.t2.unh.edu/nltapa/Pubs/fhwa's _roadway_departure_program.pdf Vulnerable Road users Motorcycles, bikes, pedestrians • Bicyclists and Other Cyclists (DOT-HS-810-986) • http://onlinepubs.trb.org/Onlinepubs/nchrp/nchrp_rpt_500v10.pdf • http://onlinepubs.trb.org/onlinepubs/nchrp/nchrp_rpt_500v22.pdf Children