Factors Affecting Highway Safety in Louisiana

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1 Factors Affecting Highway Safety in Louisiana Conducted by the Louisiana Transportation Research Center for the Louisiana Department of Transportation and Development

2 Results Fatality rates Fatalities per 100 million VMT LA AL AR CO KY MS OK TN FL TX USA States

3 Objective Identify and quantify factors contributing to the high crash record in Louisiana Identify and prioritize countermeasures that address the factors identified above

4 Data Louisiana Crash Database ( ) Louisiana DOTD Crash Database ( ) Louisiana DOTD segment data ( ) Fatality Analysis Reporting System (FARS) General Estimates System (GES) LSU Highway Safety Research Group website NHTSA Traffic Safety Fact documentation

5 Methodology Identify crash rates of subsections of crashes distinguished by the characteristics of the drivers, occupants, vehicle, or roadway. For example, crash rates of: Male and female drivers Number of occupants in vehicle Type of vehicle Class of roadway Compare crash rates of subsections between Louisiana and: Peer states (Alabama, Arkansas, Colorado, Kentucky, Mississippi, Oklahoma, and Tennessee) Rest of the nation

6 Statistic to compare between datasets z x x n n L b L b p where, total x n p(1 crash L L x n b b L L same in same in x n p) x n crash b b 1 n L frequency peer peer 1 n b of state frequency in state or or crash category in nation Louisiana nation Louisiana

7 Measuring over representation Over Representation Factor (ORF) = x x L b n n L b Example: If 45% of all crashes in Louisiana are alcohol related while only 38% of crashes in peer states are alcohol related, then ORF for alcohol related crashes in Louisiana = 0.45/0.38 = 1.2

8 Statistic to compare within a dataset Relative Crash Involvement Ratio (RCIR) RCIR x at fault, group i not at fault in multivehiclecrashes, group i x group i multivehiclecrashes, group i Example: Young drivers (15 17) are involved in 20,000 crashes/year in which they are at fault in 12, ,000 of all the crashes of this group are multivehicle crashes, in which they are not at fault in 5,000. Then, 12,000 RCIR n n 20,000 5,000 15,

9 Identifying problem areas High ORF combined with high percentage of crashes indicated a potential problem area Further analysis to try to identify root source of problem (e.g. high crash rate among young drivers is probably not associated with age per sé but possibly with inexperience, peer pressure, alcohol, and risk taking) No one statistic adequate to determine root causes

10 Addressing problem areas Countermeasures from literature (Highway Safety Manual and other sources) Crash Reduction Factors (CRFs) used to quantify effect of countermeasures to reduce incidence of crashes Mixed Logit model developed to estimate change in crash severity resulting from use of countermeasures

11 Prioritizing countermeasures Premise: priority depends on Extent of the need the countermeasure addresses Performance of countermeasure in alleviating need The cost of the countermeasure Priority index where, Need x Performance Cost 3 x x Li bi Need xlici i severity level i nl n ( ) 1 b Performance CRF Cost cost of countermeasure ($)

12 Initial identification of problem areas contributing to fatal crashes Area ORF peer ORF USA Crash % Imp peer Imp USA Alcohol related fatal crashes Fatal crashes by non use of seatbelts Fatal crashes by posted speed limit <25 mph mph mph mph Fatal crashes by drivers license Invalid CDL Non CDL license

13 Initial identification of problem areas associated with injury crashes Area ORF USA Crash % Importance Shoulder seatbelt used only (driver) Running a traffic signal/stop sign Driver age Pedestrian age Inattention/distraction Run off road injury crashes Light truck, pickup/suv Work zone One way traffic flow

14 Initial list of problem areas 23 problem areas were identified from previous analysis: Driver characteristics (8) Occupant characteristics (2) Pedestrian characteristics (2) Roadway characteristics (5) Crash characterstics (5) Vehicle characteristics (1) Further analysis conducted on these problem areas to try to determine root source

15 Seat belt non use 80.0% 70.0% 75.67% All drivers Percent seat belt non-use 60.0% 50.0% 40.0% 30.0% 61.7% 36.83% Alcohol involved drivers 20.0% 10.0% 0.0% 10.1% 9.11% 3.1% Fatal Injury PDO

16 Occupant seatbelt non use by age and gender 40 Occupant S\seat belt non-use rate Male Female Age

17 Speeding and disregarding traffic controls 800 speed related disregarding traffic control 600 Crash Rate DriverAge

18 Relative crash risk of year old drivers by number of passengers Relative crash rate fatal injury PDO Number of passengers

19 Inattention/distraction by age 20 Fatalities per 100, 000 licensed drivers Driver Age

20 Final problem areas Alcohol Young drivers Seatbelt use Licensing Speed Traffic control: stop and red signals Rural two lane roads Motorcycle safety

21 Priorities Problem area Priority Alcohol 1 Seatbelt use 2 Young drivers 3 Disregarding stop signs and red signals 4 Speed 5

22 Conclusions Human behavior most responsible for poor safety standard in Louisiana (alcohol, speeding, distraction/fatigue, low seatbelt use, invalid drivers license, repeat offences) Young drivers (<24) most culpable (3x the rate for year olds) Young males twice the fatality and injury rate of females

23 Recommendations Alter human behavior with: Point system that: Punishes bad behavior (DUI, speeding, non seatbelt use) Rewards good behavior (lower insurance, automatic driver license renewal, letter of congratulation) Extended Graduated Licensing Scheme: Increased supervised driving Limit passengers for young drivers (15 17) Promote proper and increased seatbelt use: Training of firemen, state police, and employees of state vehicle inspection facilities in proper use of child restraint systems Publicize proper use of child restraint systems, assistance available, and overall benefit of seatbelt use.

24 Impact of occupants on young male drivers year old male drivers Relative crash rate fatal injury PDO fatal injury PDO fatal injury PDO 0 14 Male occupant age groups Female occupant age groups Both male & female occupant age groups

25 Impact of occupants on young female drivers year old female drivers Relative crash rate fatal injury PDO fatal injury PDO fatal injury PDO Male occupant age groups Female occupant age groups Both male & female occupant age groups

26 Crashes by traffic control signal 80% Percent of crashes 60% 40% 20% fatal injury 0% stop yield red sig on yellow green green to yellow Traffic control signals right turn on red pdo

27 Motorcycle crash rates Fatal Injury PDO Crashes per million registered motor cycles per year

28 Impact of pavement width on crash rates 120 Non Alcohol Related 100 fatal: per 50,000,000 vmts Crahs Rate injury: per 1,000,000 vmts PDO: per 1,000,000 vmts Pavement Width (ft.)

29 Fatal off roadway crash event 40.0% 30.0% 20.0% 10.0% 0.0% Percent of Crashes Overturned Utility Pole Culvert Embankment Ditch Tree Most Harmful Event

30 Fatality rates with different measures Louisiana's relative crash rate 180% 160% 140% 120% 100% 80% 60% 40% 20% 0% Fatality per 100 Million Miles Fatality Fatality per 100,000 Population Fatality per 100,000 Registered Vehicles Fatality per 100,000 Licensed Drivers

31 Injury rates Injury 250% 200% 150% Louisiana's relative crash rate 100% 50% 0% Injury per 100 Million Miles Injury per 100,000 Population Injury per 100,000 Registered Vehicles Injury per 100,000 Licensed Drivers

32 PDO rates PDO 140% 120% % 80% Louisiana's relative crash rate 60% 40% 20% 0% PDO per 100 Million Miles PDO per 100,000 PopulationPDO per 100,000 Registered Vehicles PDO per 100,000 Licensed Drivers

FHWA/LA.11/ Title and Subtitle. Identification of Major Traffic Safety Problem Areas in Louisiana 7. Author(s)

FHWA/LA.11/ Title and Subtitle. Identification of Major Traffic Safety Problem Areas in Louisiana 7. Author(s) 1. Report No. TECHNICAL REPORT STANDARD PAGE 2. Government Accession No. 3. Recipient's Catalog No. FHWA/LA.11/434 4. Title and Subtitle 5. Report Date Statewide Traffic Safety Study Phase II: April 2012