Learning to Drive in California: Patterns in Novice Motor Vehicle Crashes and Traffic Violations in the Era of the Graduated Driver Licensing Law Scott Vincent Masten California DMV Research & Development Branch Center for Healthcare Policy and Research Seminar Series

Have you (or your spouse/partner) had a personal financial relationship in the last 12 months with the manufacturer of the products or services that will be discussed in this CME activity? ___ Yes _X_ No (If yes, please state disclosures and resolutions) Speaker’s Verbal Disclosure Statement

1. To describe how the crash rates of novice drivers change after licensure 2. To identify novice drivers with exceptionally high crash rates after the California graduated driver (GDL) licensing law was implemented 3. To discuss opportunities for reducing crash mortality and morbidity among age 18 and older novices Educational Objectives for this Seminar

CDC, WISQARS, 2014 Motor Vehicle Crashes Why should I care?  Over 2.7 million injuries per year  Leading cause of death for ages  Top 5 cause of death for ages 1-44

1.4% All-Age Causes of Death United States, 2010 CDC, WISQARS, 2014

Age Causes of Death United States, %

FARS; Fatal Year-Old Crashes United States, Annual  2,500 teen driver deaths (180 California)  1,600 teen passenger deaths (170 California)  10% of all crash fatalities are teens

Crash Rates by Driver Age United States, 2000 Crash rates decrease as age increases Highest rates among teens Many teens are just learning to drive (novices)

First Crash Incidence Each Month After Licensed to Drive Unsupervised Novice teen crash rates decrease markedly during the first year They continue to decrease at a slower rate for years Even a little driving experience results in much lower crash rates

Graduated Driver Licensing (GDL)  Reduce risk while experience gained  Implemented in all U.S. jurisdictions  Restrictions on novice teen driving are gradually removed in three stages: 1. Learner Stage May drive only with a licensed adult May drive only with a licensed adult 2. Intermediate Stage Unsupervised, but driving restrictions: Unsupervised, but driving restrictions: Nighttime Nighttime Passengers, usually other teens Passengers, usually other teens 3. Unrestricted (full) Driving Stage

Graduated Driver Licensing and Fatal Crashes Involving 16- to 19-Year-Old Drivers Scott V. Masten, Robert D. Foss, & Stephen W. Marshall

Nationwide Evaluation of GDL Design  Pooled cross-sectional time series Data  Fatality Analysis Reporting System (FARS)  Driver fatal crash involvements  Passenger vehicles  All states & D.C.  , quarterly  State-age group-quarters  Population data from the U.S. Census

Nationwide Evaluation of GDL Analysis  Poisson regression with GEEs  Separate models ages 16, 17, 18, 19, &  Control for non-GDL law changes, crude exposure, economic conditions  Trend & seasonality adjusted by state & age  Adult crash rate covariates - unmeasured confounders

U.S. Teen Fatal Crashes Post-GDL Age 16 crashes lower under GDL Age 18 crashes higher under GDL

Evaluation of the California Graduated Driver Licensing (GDL) Program Scott V. Masten & Robert A. Hagge Note: Originally completed in 2004; updated data presented here

 Implemented July 1998  Applies to all drivers licensed age <18 1. Learner Stage Min age 15; 15½ starting 2004 Min age 15; 15½ starting mo. mandatory learner permit 6 mo. mandatory learner permit 50 hours supervised practice 50 hours supervised practice 2. Intermediate Stage (age ≥16) Nighttime restriction - 12:00am-5:00am for 12 mo. Nighttime restriction - 12:00am-5:00am for 12 mo. 11:00pm-5:00am starting :00pm-5:00am starting 2006 Passengers – None < age 20 for 6 mo. Passengers – None < age 20 for 6 mo. 12 mo. starting mo. starting Unrestricted (full) Driving Stage Min age 17; automatic at age 18 Min age 17; automatic at age 18 The California GDL Program

1.How did CA population-based teen crash rates change after GDL? 2.How did CA driver-based teen injury crash rates change after GDL? 3.How did CA licensure rates change after GDL? Research Questions

Study Data  Statewide Integrated Traffic Records (SWITRS)  Driver injury crash involvements  Passenger vehicles  , monthly  Population data from the U.S. Census  License data from DMV

California Crashes, per capita Age 16 crashes decreased after GDL Age crashes increased after GDL

California Crashes, per driver No decrease in age 16 crash rates per driver after GDL Age increased after GDL

California Licensure Rates Age licensure decreased after GDL Age same or increased after GDL

1.CA crashes mirror the nationwide GDL study  Lower crashes for younger teens  Higher crashes for older teens 2.CA licensure rates after GDL:  Lower for ages  Same or higher for ages Study Conclusions What’s going on with older CA teens after GDL?

Crash Rates of Teens Delaying Licensure Compared with Those Not Delaying Licensure Eric A. Chapman & Scott V. Masten

 Nationally, GDL associated with higher 18–19- year-old fatal crash rates ( Masten, Foss, & Marshall, 2011; Masten & Hagge, 2003)  Nationally, GDL associated with higher 18–19- year-old fatal crash rates (Fell, Jones, Romano & Voas, 2011; Males, 2007; Masten, Foss, & Marshall, 2011; Masten & Hagge, 2003)  Possible mechanisms: 1.More 18–19 Novices: Delayed licensure to avoid GDL 2.Lower 18–19 Competency: GDL limits real- world driving experience Study Background

1.Do CA teens appear to delay licensure to avoid GDL? 2.How do CA teens who delay licensure drive compare to their same-age peers? 3.How do CA teens who delay licensure compare to novices of other ages? Research Questions

 Data  Random 10% of CA newly-licensed (novices), 1999–2007 (post-GDL)  3-year total & fatal/injury crashes  Analyses  Age of novice CA licensure  Novices vs. same-age peers licensed 1 or 2 years prior  Separate Poisson models 18, 19, 20, 21–24, & 25–35  Different-aged novices vs. each other Method

Age of Novice Licensure, Fewer at 17, suggesting… Delayed licensure until 18 Most novices at 16 or 18

Age 18 Novices vs. Age 18 Experienced Licensed at 18 (avoided GDL) Licensed at 17 (GDL) Licensed at 16 (GDL) Note: Rates adjusted for sex, year, & month of licensure.

Age 19 Novices vs. Age 19 Experienced Licensed at 19 (avoided GDL) Licensed at 18 (avoided GDL) Licensed at 17 (GDL) Note: Rates adjusted for sex, year, & month of licensure.

Age 20+ Novices vs. Age 20+ Experienced Age 20 Ages Experience associated with fewer crashes for all ages… Novices of all ages are worse drivers than same-age peers. Ages 25-35

Novices of Different Ages (Total Crashes) 18 novices start out worse than everyone… Even younger novices One age group does not fit the pattern Drop Note: Rates adjusted for sex, year, & month of licensure.

Novices of Different Ages (Fatal/Injury) Again 18 novices are worse than everyone 18 Does this explain the higher crash rates after CA GDL? Drop 19 novices also bad 19 Note: Rates adjusted for sex, year, & month of licensure.

Do CA teens appear to delay licensure to avoid GDL? Yes:  Fewer teens licensed at 17  Licensure pops up again at 18 Research Question #1

How do CA teens who delay licensure drive compare to their same-age peers? They have h igher crash rates:  CA 18 and 19 year-olds who delay licensure crash more than their same-aged peers…  But this is true for novices of all ages compared to their same-age peers Research Question #2

How do CA teens who delay licensure compare to novices of other ages? They have h igher crash rates:  Delaying 18 year-olds have higher total and fatal/injury crash rates than other novices.  Delaying 19 year-olds have higher fatal/injury crash rates than other novices. Research Question #3

 Some CA teens appear to delay licensure until age 18: No GDL or driver education.  novices who avoid GDL are worse than ALL other novices, even younger teens  Was this a result of implementing GDL?  All novices worse than their experienced peers: GDL may benefit novices of all ages. Study Conclusions

Crash and Traffic Violation Rates Before and After Licensure of Novice California Drivers Subject to Different Driver Licensing Requirements Eric A. Chapman, Scott V. Masten, & Kelly K. Browning

 When novice teens begin to drive unsupervised their crashes increase radically, even under GDL programs (Lewis-Evans, 2010; Mayhew et al., 2003; VicRoads, 2008)  Crash rates decrease dramatically within the first months of licensure, but remain high vs. older novices (Lewis-Evans, 2010; Masten & Foss, 2010; Mayhew et al., 2003; Twisk & Stacey, 2007; VicRoads, 2008)  Inexperience may cause high initial crash rates; teen rates may remain elevated because of overconfidence (Ericsson, Krampe, & Tesch-Römer, 1993) Study Background

1.How do crash and traffic violation rates of novice CA 16–17-year-old drivers licensed under GDL change over time? 2.How do the rates for novice drivers age 18 and older not licensed under GDL change over time? 3.How do the types of traffic violations vary during the course of licensure? Research Questions

 Data  All novices licensed in CA at age 16 or 17 ( )  10% sample of all age 18 to 35 novices ( )  3-year post-licensure crashes and traffic violations  Traffic violations categorized as inexperience-related vs. overconfidence-related  Analyses  Length learner permits are held by age  Crash and traffic violation rates over time  Overall & subtypes (e.g., fatal/injury, inexperience)  Separate Poisson models 16, 17, 18, 19, 20, 21–24, 25–35 Method

Learner Permit Holding by Age  Majorities of age 16 (57%) and age 17 (73%) hold learner permits longer than the required 6 months  31% of age 16 and 49% of age 17 hold permits for 9+ months  Majorities of age 18+ novices hold learner permits less than 6 months

Total Crash Rates Crash rates for all novices decrease most during 1 st year of driving Peak rates typically 2 nd or 3 rd month Age 18+ ramp-up of crashes before licensure

Fatal/Injury Crash Rates Age 18 and 19 novices initially crash more than younger novices Pre-licensure rates highest for age 18+

1.Crash rates of most novices are highest immediately after licensure 2.They decline quickly during their 1 st year 3.Then decline slower for the 2 nd and 3 rd years Crash Rate Findings Just like classic learning curves

4.Post-licensure crashes are higher for some age 18+ novices than those for ages 16–17 5.Pre-licensure crash rates for age 18+ novices ramp up immediately before licensure  Suggests they try to learn to drive during a very short time period  Contrary to good learning methods (spaced practice) 6.70% of age 16–17 novices are crash-free for the first 3 years of licensure Crash Rate Findings (cont)

Total Traffic Violation Rates Traffic violations for age 16 and 17 novices peak long after their crashes, around the time when they are age 18 Age 18+ violations highest during 1 st year or pre-license Wow

Inexperience vs. Overconfidence Violations Age 16-17: inexperience & overconfidence violations peak after crashes, when they turn age 18 Age 18+: inexperience and overconfidence violations peak 1 st year of licensure, when crashes peak too Inexperience Overconfidence

1.Age 16–17 novices’ traffic violation rates peak long after their crashes peak (when age 18) 2.Violation rates for age 18+ novices peak during their 1 st year of licensure. 3.Inexperience and overconfidence violations typically peak around the same time 4.45% of age 16–17 novices are traffic violation- free for the first 3 years of licensure Traffic Violation Rate Findings

1.Age 16–17 novices typically hold learner permits for longer than minimum 6 mo. 2.Older CA novices appear to rush learning to drive; do not hold permits very long 3.Novices driver crash rates for most ages follow a classic learning curve 4.Novice driver violation rates do not follow a classic learning curve—proxy for exposure Study Conclusions

1. To describe how the crash rates of novice drivers change after licensure Pattern follows classic learning curve Pattern follows classic learning curve Highest immediately after licensure Highest immediately after licensure Decrease dramatically during the 1 st year Decrease dramatically during the 1 st year Decrease at a slower rate subsequently Decrease at a slower rate subsequently Review of Educational Objective #1

2. To identify novice drivers with exceptionally high crash rates after the California graduated driver (GDL) licensing law was implemented Age crashes increased after GDL Age crashes increased after GDL Age crash rates now higher than all other novices, even younger teens Age crash rates now higher than all other novices, even younger teens Review of Educational Objective #2

3. To discuss opportunities for reducing crash mortality and morbidity among age 18 and older novices Given that age 18+ novices appear to cram learning to drive into a short period… Given that age 18+ novices appear to cram learning to drive into a short period… Maybe they would benefit from minimum learner permit holding periods Maybe they would benefit from minimum learner permit holding periods Given that age 18+ novices are also worse than their experienced peers… Given that age 18+ novices are also worse than their experienced peers… Maybe they would benefit if GDL was extended to them, particularly for ages Maybe they would benefit if GDL was extended to them, particularly for ages Review of Educational Objective #3

Thank you! Questions & Discussion Scott V. Masten