The impact on alcohol-related collisions of the partial decriminalization of impaired driving in British Columbia, Canada

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ContentslistsavailableatSciVerseScienceDirect

Accident

Analysis

and

Prevention

jo u r n al ho me p a g e :w w w . e l s e v i e r . c o m / l o c a t e / a a p

The

impact

on

alcohol-related

collisions

of

the

partial

decriminalization

of

impaired

driving

in

British

Columbia,

Canada

夽

Scott

Macdonald

a,b,∗

_,

_Jinhui

_Zhao

a

_,

_Gina

_Martin

a

_,

_Jeff

_Brubacher

c

_,

_Tim

_Stockwell

a,d

_,

Neil

Arason

e

_,

_Susanne

_Steinmetz

e

_,

_Herbert

_Chan

c

a_Centre_for_Addictions_Research_of_BC,_University_of_Victoria,₂₃₀₀_McKenzie_Avenue,_BC,_Canada_V8P_5C2 b_School_of_Health_information_Science,_University_of_Victoria,₂₃₀₀_McKenzie_Avenue,_BC,_Canada_V8P_5C2

c_Department_of_Emergency_Medicine,_University_of_British_Columbia,₉₁₀_West_10th_Avenue,_Vancouver,_BC,_Canada_V5Z1M9 d_Department_of_Psychology,_University_of_Victoria,₂₃₀₀_McKenzie_Avenue,_BC,_Canada_V8P_5C2

e_The_Ofﬁce_of_the_{Superintendent}_of_Motor_Vehicles,_British_Columbia_Ministry_of_Justice,_P.O._Box_9254,_STN_Prov_Govt,_Victoria,_BC,_Canada_V8W_9J2

a

r

t

i

c

l

e

i

n

f

o

Articlehistory: Received2March2013

Receivedinrevisedform10May2013 Accepted15May2013

Keywords:

Immediateroadsideprohibitions Alcohol-relatedcollision Interruptedtimeseriesdesign

a

b

s

t

r

a

c

t

Introduction:Thepurposeofthispaperistoassesstheimpactofadministrativesanctionsintroducedas

partofanewlawfordrinkingdriversinBritishColumbia,Canada.Thenewlaw,knownasimmediate

roadsideprohibitions(IRP),aimedtoincreasetheefﬁciencyofpoliceandcourtsforprocessingdrinking

drivers,therebyincreasingthecertaintyoftheirbeingapprehendedandpunished.However,inorderto

maintaintheseefﬁciencies,sanctionsunderthisnewlawlargelyreplacedlawsundertheCriminalCodeof

CanadaforDrivingWhileImpaired(DWI)byalcohol,whichhadmoreseverepenaltiesbutlowercertainty

ofpunishment.Weexaminedwhethertheinterventionwasrelatedtoabruptsigniﬁcantdeclinesinthree

typesofalcohol-relatedcollisions(i.e.fatalities,injuriesorpropertydamageonly)comparedtothesame

typeofcollisionswithoutalcoholinvolvement.

Methods:Aninterruptedtimeseriesdesign,withanon-equivalentcontrolwasused,testingforan

inter-ventioneffect.Monthlyratesofthethreetypesofcollisionswithandwithoutalcoholinvolvementwere

calculatedforthe15-yearperiodbeforeandthe1-yearperiodafterimplementationofthenewlaw.

ARIMAtimeseriesanalysiswasconductedcontrollingfortrendeffects,seasonality,autocorrelation,and

collisionswithoutalcohol.

Results:Signiﬁcantaveragedeclines(p<0.05)inalcohol-relatedcollisionswerefoundasfollows:40.4%

forfatalcollisions,23.4%forinjurycollisionsand19.5%forpropertydamageonlycollisions.Nosigniﬁcant

effectswerefoundforanyofthethreecomparablenon-alcohol-relatedtypesofcollisions.

Conclusions:Theseresultssuggestthatprovinciallawofadministrativesanctionsfordrinkingdrivers

andassociatedpublicitywasmoreeffectiveforminimizingalcohol-relatedcollisionsthanlawsunder

theCanadianCriminalCode.

1. Introduction

Experimentalresearchhasconﬁrmedthedeleteriouseffectsof

alcoholonsensory,cognitiveandmotorfunctionsneededfor driv-ing(LiuandHo,2010).Similarly,epidemiologicalstudiesclearly

show that risk of a collision increases exponentially as Blood

AlcoholConcentration(BAC)increases(Blombergetal.,2009).In

夽 Thisisanopen-accessarticledistributedunderthetermsoftheCreative Com-monsAttribution-NonCommercial-NoDerivativeWorksLicense,whichpermits non-commercialuse,distribution,andreproductioninanymedium,providedthe originalauthorandsourcearecredited.

∗ Correspondingauthorat:CentreforAddictionsResearchofBC,Room273,2300 McKenzieAvenue,UniversityofVictoria,BC,CanadaV8P5C2.Tel.:+12504725933; fax:+12504725933;mobile:+12502131669.

E-mailaddress:scottmac@uvic.ca(S.Macdonald).

Canada,estimates from2008 indicate that close to 600fatally

injureddrivershadbeendrinking(CanadianCentreonSubstance

Abuse,2011).Injuriesanddeathsassociatedwithalcoholimpaired

drivinghave led manycountries toadoptvarious penalties for

drivingwithaBACgreater thana setper selevel(Mannetal.,

2001).Theseinterventionsareguidedbythedeterrencemodel,

whereperceivedcertainty,severityandswiftnessofpunishment

fordrinkinganddrivingarethoughttocontributetoreductions

inthis behaviour(Mannetal., 2001;Vingiliset al.,1988).

Sev-eralstudies have founda decrease in alcohol-related collisions

associatedwithlowerperselimits(Wagenaaretal.,2007;Mann etal.,2001).Recentresearchfoundasigniﬁcantinterventioneffect ontotalfatalitieswhen90dayadministrativelicencesuspensions

wereimplementedatthe80mg/100mllevelinOntario(Asbridge

etal.,2009).Researchsuggeststhatincreasingperceivedcertainty

ofbeingcaughthasagreaterimpactonchangingbehaviourthan

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increasingtheseverityofthepunishment.Littleresearchhasbeen

conductedontheswiftnessofpunishmentalthoughithasbeen

speculatedtobeimportant(NaginandPogarsky,2001;Jiang,1994). Additionally,publicityofthelawsisanecessaryconditionfor effec-tiveness(Vingilisetal.,1988).

UndertheCriminalCodeofCanada,itisacriminaloffenceto DriveWhileImpaired(DWI)byalcoholwithaBAC>80mg/100ml,

ortorefuse a breath test.However, enforcementof theselaws

istimeconsumingandexpensiveforboththepoliceandcourts.

Collectingevidencebypolicerequiressophisticatednon-portable evidentialbreathtestingequipmentinthepolicestationand con-siderablepaperwork.Researchhasshowedthatasinglechargefor

impaireddrivingbyalcoholunderCriminalCode tookpolicean

averageof2h48mintoprocessand4hofpolicetimeincourt,if thecasegoestotrial(Jonahetal.,1999).Although,theperselimit

fortheCanadianlawis80mg/100ml,researchshowsthat

driv-ingatlowerBAC’sat50mg/100mlis associatedwithincreased

collisionrisk(Blombergetal.,2009).In responsetothis,nearly allCanadianprovincesandterritorieshaveenactedadministrative sanctionsfordriverswithBAClevelsbetween40and80mg/100ml (ChamberlainandSolomon,2002).

BritishColumbia(BC)introducednewimmediateroadside

pro-hibition(IRP)sanctionsfordrinkingdriversonSeptember20,2010

in order to addresssome limitations of the Canadian law.The

newsanctionsweredesignedtomaximizethedeterrenteffectby

increasingthecertainty,severityandswiftnessofsanctions.

Cer-taintyofdetectionwasincreasedbyreducingtheadministrative

timetochargeoffenders.Sincelesspoliceandcourtresourcesfor

chargingandconvictingindividualswererequiredunderthenew

provinciallaw,policewereabletospendamuchgreaterproportion oftheirworkdirectedtowardsdrinkinganddrivingdetectionand enforcement.Theprovinciallegislationrequiredmuchless

paper-workandusedevidencegatheredattheroadsidefromaportable

handheld breathalyzer device. Compared to the old provincial

laws,thenewBClegislation alsoincreasedtheseverityof

pun-ishmentfordriverswithBAClevelsbetween50and80mg/100mL,

andemphasizedswiftnessofsanctions.FordriverswithBAC

lev-elsbetween50and80mg/100ml,thenewpenaltiesincludedan

immediate3daysdriver’slicencesuspension(upfroma24h

sus-pension)andpossiblevehicleimpoundment.FordriverswithBACs

over80mg/100ml,thenewpenaltiesincludedanimmediate90

daylicensesuspension(ratherthana21daywaitperiod)anda

mandatory30 dayvehicleimpoundment. A mandatory

respon-sibledriverprogramme andanignitioninterlockdeviceintheir

vehiclewererequiredforthosedriverswhowishedtore-instate

theirdriver’slicence(MinistryofJustice,2012).Finally,the

imple-mentationof these sanctions wasimmediate, thus maximizing

swiftness.However,inordertoachievetheseaforementioned efﬁ-ciencies,drinkinganddrivingoffendersneededtobechargedunder

provincial legislation rather than theCriminal Code of Canada.

Thus,provincialoffenderswouldnotreceiveacriminalrecordthat couldhavelong-termnegativeconsequences,suchastravel

restric-tionsoutsidethecountryorreducededucationalandemployment

opportunities.

Inorderforanewinterventiontobeeffective,citizensmustbe

awareofit.Bothpublicawarenesscampaignsandmediaattention

helped tomaximize awareness. Criticism that the new

legisla-tionwastoostrictandfailedtoallowthoseaccusedafairappeal

attractedconsiderablemediaattention.Potentialunfairnesswas

highlightedinmediareportsindicatedthatasmanyas100

hand-heldbreathalyzerswerecalibratedincorrectlyandwereunreliable atcertaintemperatures(Theodore,2011).OnNovember30,2011, theBCSupremeCourtruledthatpartoftheIRPlegislationinfringed

on the Federal Charter of Rights and Freedoms because those

chargedcouldnotmeaningfullychallengeresultforBACsabove

80mg/ml(i.e.90dayfail).Thenewlawthatappliedtothosewith

BACabove80mg/mlweresuspendeduntilJune15th,2012,when

amendedlawswereintroduced.Thelawfor50mg/mlremainedin

effectthroughouttheentirepost-interventionperiod.Inaddition tothemediaattention,thegovernmentinitiatedanumberof

pub-licawarenessactivitiesandeventsremindingdriversofthenew

legislationandextrapoliceenforcement.

TheBCGovernmentnoteda40%dropinalcohol-relatedroad

fatalitiesintheyearfollowingthenewlawscomparedtothe pre-vious5yearaverage(MinistryofJustice,2011).Inthisstudy,we

conductedamoresophisticatedevaluationusing15yearsof

pre-interventiondata with2years ofpost-interventiondata,taking

intoaccounttrends,seasonality,autocorrelationandmoving aver-ageeffects.Wealsocontrolledfortrendsinnon-alcohol-related

collisions in order toaccount for potential confounding effects

ofother factorsthatmayaffectallcollisions, suchasimproved roadconditionsorotherroadsafetyinitiatives.Finally,we

con-ducteda newspapermediaanalysistoassesswhethertheissue

ofdrinkinganddrivingreceivedincreasedcoverageafterthenew legislation.

2. Hypotheses

Theaimofthisstudyistoexaminetheimpactofthenewlawson threetypesofalcohol-relatedcollisions:fatalcollisions,injury col-lisions,andpropertydamageonlycollisions.Sincetheintervention

wasaimedspeciﬁcallyatalcohol-relatedcollisions,we

hypothe-sized thata successfulinterventionwould beassociatedwitha

significantdeclineinalcohol-relatedcollisionsandnochangein thosewithoutalcohol.Specifichypotheseswereasfollows:(1) sig-nificantdeclinesinthreetypesofalcohol-relatedcollisionswould

be foundin relationto theintervention, and (2) no signiﬁcant

declineswouldbefoundinrelationtotheinterventionsforthree typesofcollisionswithoutalcohol.

3. Methods

The study is an interrupted time series design with a

non-equivalentcontrolgroup.Dataincludedmonthlycountsofpolice

reported:(a)fatalcollisions,(b)injurycollisions,and(c)property damageonlycollisions.Collisionsweredeemedtobealcohol-related ifpolicecited“alcoholinvolvement”,“alcoholsuspected”,or

“abil-ity impairedbyalcohol”as a contributoryfactor for anydriver

(includingcyclists)orpedestrianinvolvedinthecrash.Fatalities wereregisteredwhenavictimdieswithin30daysofacollision. Injuriesrefertocollisionsresultinginanylevelofinjurybutnot death.Propertydamageonlycollisionsarethosewherepolicewere

inattendanceandcompletedareportoftheincident.Policeare

legallyobligatedtoattendallfatalcollisionssothecountoffatal

collisionswascomprehensive.Thecountsofinjuryandproperty

damageonlycollisionswerenot comprehensive,aspolice were

notrequiredtoattendallofthese.In2006,approximately41%of injurycollisionsand24%ofpropertydamagecollisions,compared

toinsurancedata,werereportedbypoliceand includedinthis

data.By2010,about34%ofinjurycollisionsand19%ofproperty

damagewereincludedinthepolicedatabase.Sinceouranalytic

approachwastoassessadifferentialeffectforalcoholand non-alcohol-relatedcollisions,wedonotseethislackofcomprehensive dataasa majorlimitation.Countsofeachtypeofcollisionwith

andwithoutalcoholwereaggregatedbymonthanddividedbythe

numberofmonthlylicenseddriversestimatedusingcubicspline

interpolation (DeBoor,1981; Mcneil et al., 1977) multipliedby 1,000,000toproducerates.Monthlycollisionrateswereadjusted

toaccountfornumberofdaysinthemonth.Datawerecollected

for177monthsbeforeand24monthsaftertheintervention,

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decidedaprioriinordertoexceedtherecommendedminimum

numberofobservations(50observations)requiredforanARIMA

model(BoxandJenkins,1976).Ethicsapprovalwasobtainedfrom theUniversityofVictoria(#12-029).

Data were analyzed withARIMAmodels that controlled for

trends,seasonality,autocorrelationand/ormovingaverageeffect patterns(McDowalletal.,1976).Timeseriesmodelsforeachtypeof alcohol-relatedcollisionweredevelopedtoexamineeffectsofthe interventionforthe2-yearperiodafteritwasintroduced.October 1,2010wastreatedastheinterventiondateasthiswastheﬁrst fullmonthafterthelegislationwasineffect.Someinitial

trans-formationswereconductedinordertomeettheassumptionsof

ARIMA. Firstthelogarithm of collisionrates wasusedto make

variancestationary.Second,thedifferenceofthecollisionseries

fromoneperiodtothenextwascalculatedtoremovethetrend

overtime.Finally,aseasonalARIMAmodelforthelog-transformed rateswasidentiﬁed,withdifferencingrequiredatlags1and12to eliminatetheseasonalandtrendeffects(i.e.thecurrent period-to-periodcollisionsandthechange12periodsago).Fatal,injury

andpropertydamageonlycollisionswithoutalcoholinvolvement

wereusedascontrolvariablestoaccountforothergeneral

condi-tionsthatcouldpotentiallyconfoundtheresults.Wethenadded

theinterventionindicatorandtransferfunctiontoassesswhether signiﬁcantchangesinalcohol-relatedcollisionsoccurred2years aftertheintervention(BoxandJenkins,1976;SASInstitute,2011).

Themodelwasﬁttedbytheconditionalleastsquaresmethodand

theeffectwastestedasabruptandpermanent.Wealsoconducted

similaranalysestoassesswhethertheinterventionwasassociated withasigniﬁcantchangeforthethreetypesofnon-alcohol-related collisions.Aconservativetwotailedtestwasusedatthe5%levelof signiﬁcance.

Inordertoassesswhetherotherinterventionsmayhave

inﬂu-encedalcohol-relatedcollisions,wereviewedothertrafﬁcsafety initiativesthatwereimplementedduringthe17-yearperiodofthe

study.WealsoexaminedtheintensitytheBCgovernment’s

adver-tisingofthelegislation.Additionally,toexaminemediaattentionof drinkinganddrivingbeforeandaftertheinterventionasearchwas conductedonMay7th,2013ofnewspaperarticlesthatincludedthe

searchterms:“drinkinganddriving”or“drunkdriver”or“drunk

driving”or“alcohol-relatedcrash”fromtheCanadianNewsstand

Paciﬁcdatabase,whichincludesmajorpapersaswellassmaller

dailiesandweekliesintheBCarea.Thesearchwasrestrictedto

September21st–September20thfortheyearperiodspriortoand

thetwoyearsfollowingtheIRPlaw.Finally,thenumbersofcharges

undertheoldlaws,bothprovincialandCriminalCode,andunder

thenewlawsweredocumentedforthesame1yearperiodsbefore

andafterthenewlaw.Finally,wealsodocumentedchangesinthe

numberofvariouspolicechargesrelatedtodrinkinganddriving

fortheseperiods.

4. Results

During the whole study period, there were 76,205 police

reportedalcohol-relatedcollisions,accountingforapproximately

10%of total police investigated collisions.These included1636

alcohol-relatedfatalcollisions(about8permonth),32,710

alcohol-related injury collisions (about 167 per month) and 41,859

alcohol-relatedproperty damageonly collisions(about 212per

month). Figs. 1–3 illustrate monthly rates of alcohol-related

fatal,injury and property damage onlycollisionsper 1,000,000

licensed drivers. The seasonal pattern peaked in the summer

months (July–September) and declined in the winter months

(January–March).Theseseasonalpatternswereobservedforboth

alcoholandnon-alcoholrelatedcollisions.Alcohol-relatedfatal col-lisionratesandpropertydamageonlycollisionratesappeartohave

Alcohol related fatal collision

Moving average alcohol related fatal collision

Intervention 0 1 2 3 4 5 6 7 8 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 20112012

Alcohol related fatal collision rate

Date

Fig.1.Monthlyalcohol-relatedfatalcollisionrateper1,000,000licenseddriversin BC,1996–2012.

Alcohol related injured collision

Moving average alcohol related injured collision

Intervention 0 20 40 60 80 100 120 19961997199819992000200120022003 200420052006200720082009201020112012

Alcohol related injured collision rate

Date

Fig.2.Monthlyalcohol-relatedinjuredcollisionrateper1,000,000licenseddrivers inBC,1996–2012.

Alcohol related property damage only collision

Moving average alcohol related property damage

only collision

Intervention

0 20 40 60 80 100 120 1 7 1 7 1 7 1 7 1 7 1 7 1 7 1 7 1 7 1 7 1 7 1 7 1 7 1 7 1 7 1 7 1 7 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 20112012 Al cohol r elat ed pr op ert y d ama ge onl y c ol lis ion ra te Date

Fig.3.Monthlyalcohol-relatedpropertydamageonlycollisionrateper1,000,000 licenseddriversinBC,1996–2012.

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Table1

Interventioneffectsforalcohol-relatedfatal,injuryandpropertydamageonlycollisionscontrollingforcomparablenon-alcohol-relatedcollisions,trendandseasonality (bydifferencing),movingaverageandautocorrelation(BritishColumbia,1996–2012).

Parameter Estimate Standarderror Probabilityvalue

ModelI:alcohol-relatedfatalcollisions

Movingaverageatlag1 0.835 0.041 <0.0001

Autocorrelationatlag8 −0.140 0.071 =0.0486

Autocorrelationatlag12 −0.477 0.071 <0.0001

Interventioneffect −0.518 0.254 =0.0428

Non-alcohol-relatedfatalcollision −0.030 0.119 =0.8011

Effectsize(R2₎ _52.6%

ModelII:alcoholinvolvedinjurycollisions

Interventioneffect −0.267 0.069 =0.0001

Non-alcohol-relatedinjurycollision 0.249 0.113 <0.0293

ModelIII:alcohol-relatedpropertydamageonlycollisions

Autocorrelationatlag1 −0.181 0.074 =0.0155

Interventioneffect −0.217 0.071 <0.0001

Non-alcohol-relatedpropertydamageonlycollision 0.145 0.071 =0.0438

begundecliningin2007,whileinjuredcollisionratesbeganmoving downwardsin2005.

Basedontheantilogoftheparameters,theinterventionwas associated with a 40.4% (95% CI: 2.0–63.8%) mean reduction in alcohol-related fatal collisions, a 23.4% (95% CI: 12.4–33.1%) reductioninalcohol-relatedinjury collisionsand 19.5%(95%CI: 10.5–27.6%)reductionofalcohol-relatedpropertydamageonly col-lisions.Thesepercentages translateinto anannualreduction of approximately44(95%CI:2–69)alcohol-relatedfatal collisions, 487(95%CI:257–687)alcohol-relatedinjury collisionsand 508 (95% CI: 274–718) alcohol-related property damage only colli-sions.Intheforegoinganalysis,non-alcohol-relatedcollisionswere treatedasacovariate(seeTable1).Additionalanalyseswere

con-ductedtoassesswhethertheinterventionwasrelatedtochanges

inthesethreetypesofcollisionswithoutalcohol.Ineachanalysis, theinterventioneffectwasnotsigniﬁcant(fatal,p=0.18;injury,

p=0.96; property damage, p=0.20) indicating the intervention

effectwasonlyspeciﬁctoalcohol-relatedcollisions.

Inthe17 yearstudyperiod, therewere22 legislativetrafﬁc

safetyinitiativesenactedandeightcouldpotentiallyhavehadsome bearingondrinkingdrivers.However,allalcohol-related interven-tionswereinitiatedbeforeSeptember,2010andthereforearenot potentialconfoundersrequiringstatisticalcontrolforan interven-tioneffect.Someinterventionsbefore2010wereaimedatreducing

alcohol-relatedcollisions.Forexample,in 2005aremedial

pro-gramme(i.e. educationalcourse) and ignition interlock devices

wereimplementedfordrinkinganddrivingoffences.In2006,

for-feiture ofvehiclebecame a possibleconsequence for convicted

drunkdrivers.

Theintensityofprovincialadvertisingofthenewlawand

asso-ciated publicity was assessed. In addition, a number of public

awarenessactivities,involvinganumberofroadsafetypartners,

occurredbetweenJuly2010andDecember2010especially.The

componentsincluded:aredevelopedwebsiteonimpaireddriving

andthenewlaws;televisionandradioadvertisementsthat encour-agepeopletodrinkresponsiblyandtoreminddriversofextrapolice

enforcement;holiday-themedwashroomads, theuseofposters

andcoasterswithmessagesontheminbarsandrestaurants.

TheintroductionoftheIRPprogrammewasaccompaniedby

agreatdealofmediaattentionwhichelevatedtheawarenessof

thenewlaw.Newspaperreportsondrinkingand drivinginBC

increasedfrom978in2009–2010to1307in2010–2011,a34%

increase.In2011–2012thenumberofmediareportsdecreasedto

1053.

Table2showsthechangesthatoccurredinchargesand

sanc-tionsforthe1 yearperiodbeforethenewlawand two1 year

periodsafterwards.ThenumberofCriminalCodechargesinBC

droppedsubstantially from9079intheyearprecedingthenew

lawstoonly2890inthefollowingyear,a68.2%decline.Charges

for administrativedrivingprohibitions undertheold provincial

lawdeclinedfrom33,288to3719fortheyearperiodsbeforeand

afterthenewlaw.Asexpected,immediateroadsideprohibitions

increaseddramaticallyfrom630(allgivenoutinthelastdaysof September)intheyearbeforeto22,725chargesafterthenewlaw. Interestingly,thetotalnumberofalldrinkinganddrivingcharges

decreasedover thethreetimeperiodsfrom33,918to26,435,a

22.1%declineandafurtherdeclineto21,571chargesinthesecond yearaftertheIRPlaw.

5. Discussion

Thedeclineineachtypeofalcohol-relatedcollisionis

consis-tent with ourhypothesis that a real changein drinking driver

behaviouroccurred. In this study,we used time-seriesanalysis

toassesswhethersigniﬁcantchangesinalcohol-relatedcollisions

occurredafterthenewlegislationwasimplemented.We found

significantreductionsinalltypesofalcohol-relatedcollisions, con-sistentwithapositiveeffectoftheintervention.Inordertoaccount forroadsbecomingsaferwithnewtrafficsafetymeasures,weused non-alcohol-relatedcollisionsineachofthreecategoriesas con-trolvariables.Wereasonedthatasuccessfulinterventionshould haveaspecificimpactonalcohol-relatedcollisionswithlittleeffect

oncollisionswithoutalcohol. Since we include collisions

with-outalcoholasacovariatetoassesstheinterventioneffectofthe

alcohol-relatedcollisionsandsinceseparateanalysesshowedno

interventioneffectfornon-alcoholcollisions,weareconﬁdentthat thereductionsinalcohol-relatedcollisionsareduetothe

interven-tion(includingpublicity)andnotsomeotherphenomena.Using

non-alcohol-relatedcollisionsasacontrolvariablegreatlyreduces thelikelihoodthatothergeneralizedfactors(i.e.trafﬁcsafety ini-tiatives,economicconditionsandvehiclesafety)mayhavecaused thereductioninalcohol-relatedcollisions.Wealsocontrolledfor autocorrelationeffects,sinceratesinonemontharemorerelated toeachotherthanthosewhicharemoredistal.Finallywereviewed othersafetyinitiativesthatmayhavereducedonlyalcohol-related collisionratesandnonewerefoundatthesametimeasthe inter-vention.

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Table2

Numberofchargesandsanctionsintheyearpriorandaftertheintervention.

Prohibitions October1, 2009–September 30,2010 October1, 2010–September 30,2011 October1, 2011–September 30,2012

AlcoholcriminalcodedrivingchargesinB.C.(Canadalaw) 9079 2890 4215b

Alcoholrelateddrivingprohibitions

24halcohol(BC) 33,288c ₃₇₁₉c ₈₀₂₁c

Administrativedrivingprohibition“fail”(BC) 9903 1576 4115b Administrativedrivingprohibition“refuse” 2021 437 812 Immediateroadsideprohibitions(IRP)

3,7or30day(BC) 262a ₇₆₉₉ ₆₀₃₆

90day“fail”(BC) 337a _13,561 ₆₄₀₁b

90day“refuse”(BC) 31a ₁₄₆₅ ₁₁₁₃

Sub-totalAllImmediateroadsideprohibitions(BC) 630 22,725 13,550

Grandtotalalldriverscharged/prohibited 33,918 26,444 21,571

Datasources:CCCdataobtainedfromtheCriminalJusticeBranchonApril8,2013. 24hprohibitiondatawasprovidedbyICBConMarch31,2013.

ADPandIRPdataextractedfromtheADP/VIdatabaseonApril16,2013.

a_Since_the_immediate_roadside_prohibitions_law_was_enacted_in_September_20,_2010,_all_these_prohibitions_were_issued_between_September_20th_and_September_30th,

2010.

b _From_November_30th₂₀₁₁_to_June_15th_2012,_the₉₀_day_“fail”_IRPs_were_temporarily_suspended_from_operation._Police_reverted_to_issuing_the_previous_sanctions_and

theCriminalCodeprocessfordriverswhoprovidedabreathsamplethatcontainedaBACof0.08andabove.

c _Note:_All_drivers_with_a_criminal_code_charge_or_an_{administrative}_driving_prohibition_also_received_a₂₄_h_suspension.

ConvictingdriversofimpaireddrivingundertheCriminalCode

ofCanadaisadifﬁcultandlengthyprocessandmanyapprehended

impaireddriversavoidCriminalCodesanctionsaltogether.In

com-parison,BC’s newlegislation is enforcedimmediately andwith

feweravenuesforappeal.Althoughtheseverityofpunishmentfor

driverswithBACbetween50and80mg/100mlincreasedfromthe

oldtonewprovinciallaw,overallseveritylikelydidnotincrease forthosewithBAC>80mg/100mlwhowerenotchargedunderthe provisionsoftheCriminalCodeofCanada,astheywouldnotreceive

acriminaloffencewithpotentiallongtermconsequences.

How-ever,2890driverswerechargedundertheCriminalCodeafterthe

newprovinciallegislationwasimplemented(downfrom9079in

theyearpriortotheintervention),andthesepeoplewillhave expe-riencedgreaterseverityofsanctions.ItislikelythattheCriminal Codeoptionwaschosenbypoliceinsituationswithgreaterharms oftheoffence,suchasthosewithpersonalinjuryorwithveryhigh BACsorforrepeatoffenders.Aswell,policeofﬁcerscannotissuean IRPforalcohol-relatedcollisionstheydidnotwitness,andinthese situationsaCriminalCodechargeislikely.Thisstudysuggestsa

beneﬁcialreductioninalcohol-relatedcollisionsduetothenew

legislationbutdecisiveconclusionsregardingtherelative

impor-tanceofthethreecomponentsofdeterrencecannotbedrawn,nor

canwedistinguishbetweentheimpactoftheinterventionitself

andassociatedpublicity.

Theprovincial legislationand itsenactment raise some

fun-damentalquestionsregardingthepotentiallyconﬂictingrolesof

provincialandfederallegislationtoaddressdrinkinganddriving.

LawswithintheCriminalCodeofCanadaapplytoallCanadians

andaredesignedtosetlimitsofacceptableconductintheinterest ofmaintainingasafeandpeacefulsociety.Theselawsareintended toachievefourmultifacetedobjectives:deterrence,rehabilitation, retributionandconﬁnement(forindividualsseenasamajorthreat tosociety).Enshrinedwithintheselawsaretherightsofdue pro-cessandthepresumptionofinnocenceunlessprovedguiltybeyond areasonabledoubt.Bycontrast,provinciallegislationsuchas

traf-ﬁcsafety laws, applies onlyto peoplewithin each province or

territory.Trafﬁcsafetylawsareguidedbytheprinciplesof deter-rencetowardsmaximizingpublicsafety.Resultsofthisstudyshow

thatthegoalsofimprovedroadsafetybytheprovincial

govern-mentwereachieved.Furthermore,sinceCriminalCodeconvictions

declineddramaticallywiththenewsanctions,thestudyindicates thateffectivelegislationfordrinkinganddrivingdoesnotrequire alloffenderstoreceive aFederalcriminaloffence.Ineffect,the

68.2%reductioninCriminalCodechargesfordrinkingamountstoa partial“decriminalization”ofimpaireddrivinginBC.This decrimi-nalizationwasassociatedwithsavingsinpolicetimeandsigniﬁcant reductionsinalcohol-relatedroaddeaths,collisionsandnonfatal injuries.

Somelimitationsofthedatashouldbenoted. Ourdataonly

includedcollisionswhereapoliceofﬁcerwaspresentanda

sub-stantialproportion of collisions, especially minor ones,are not reportedtothepolice.Itisreasonabletospeculatethatcollisions involvingalcoholmaybelesslikelytobereportedtopolice, espe-cially for those thatare less severe orinvolve a single vehicle,

becauseinebriateddriverswouldbemorelikelytoevade

detec-tion.Althoughtheremaybedifferentialbiasinthemeasures,such biasislikelyconsistentovertheentiretimeperiod,andtherefore likely didnot meaningfullyeffect ourconclusions. Aswell,this limitationwouldnotapplytofatalcollisionssincepoliceare man-datedtoinvestigateallfatalcollisions.Inaddition,ourcountsof alcohol-relatedcollisionsincludedcollisionswhereapedalcyclist orpedestrianhadbeendrinking.Thesecasesarenotlikelytobe

impactedbythenewIRPsandincludingthemmayhave

underes-timatedtheeffectofthenewlaws.Aﬁnallimitationofthisstudyis thatwefocusedontheshort-termchanges(i.e.2years)in alcohol-relatedcollisionsrelated totheintervention.Somestudieshave

suggestedthattheseshort-termchangesmaynotbesustainedin

thelongerrun(Vingilisetal.,1988;Ross,1973).Therefore,further researchisrequiredtoassesslonger-termeffects.

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