The Impact of Administrative Licence Suspension and
Vehicle Impoundment for DWI in Manitoba
D. J. B e irness1, H .M . S im pson', D .R . M ayh ew 1 and B. Jon ah 2
'T raffic In ju ry R esearch Foundation , O ttaw a, C anada
'T ransport C anada, O ttaw a, C anada
O ver the past several years, adm inistrative licence suspension (A LS) has becom e a popular
m easure fo r dealing w ith D W I offenders in the U nited States, w ith 40 states curren tly using
it. T he procedure involves g iving police the pow er to seize the licence o f a d river w ho e ither
refuses to subm it to a test fo r alcohol or w ho registers a BA C in excess o f the sta tu tory lim it.
T he d river is issued a tem porary licence fo r a period o f tim e (typically seven days) to perm it
the indiv idual to m ake necessary arrangem ents fo r operating w ithou t a licence. T he key
feature o f A LS is its sw iftness — it occurs im m ediately w hen a charge is laid and is
independent o f any subsequent D W I conviction. T he results o f evaluation studies show both
general and specific deterren t effects o f A LS (Ross, 1991; S tew art et a l., 1989; W illiam s et
al., 1991).
A persistent prob lem w ith licence suspension is that m any — in fact, the m ajority — o f
suspended drivers con tinue to drive, albeit less often o r at low er risk tim es (R oss, 1991). A s a
result, the full im pact o f the suspension is com prom ised and the long-term effectiveness o f
the system po tentially eroded. For this reason, it has been suggested that the penalty for
driv ing w hile suspended (D W S) should be the rem oval o f the vehicle. A lthough m any
ju risd ic tions have such legislation , it is rarely used.
In N ovem ber 1989, M anitoba becam e the first p rovince in C anada to in troduce A LS. A t the
sam e tim e, leg islation w as im plem ented that gave police the pow er to seize and im pound for
a period o f 30 days the vehicle o f any person found to be driv ing w hile d isqualified . V ehicle
seizure and im poundm ent (V SI) w as intended to com plem ent A LS by prov id ing a m eans to
com bat the prob lem o f driv ing w hile under suspension. A lthough in tended as a D W I
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counterm easure, V SI app lied to all drivers d isqualified fo r any reason. T h is paper exam ines
the resu lts o f an evaluation o f the effects o f A LS and V SI in M anitoba .
M E T H O D
To assess the general deterren t effect o f the A LS and V SI program s, data on the B A C s o f
fatally in jured drivers w ere obtained from the T IR F Fatality D atabase fo r the years 1985
through 1995. D river record files w ere also ob tained for all persons convic ted o f a D W I
offence betw een 1985 and 1995 as w ell as all persons issued a licence suspension betw een
1985 and 1995. W here available, sim ilar data from a ne ighbouring p rov ince (i.e.,
Saskatchew an) w ere used as a com parison. A variety o f m ethods rang ing from sim ple p re
post com parisons to in terrupted tim e series analysis w ere used to exam ine changes associated
w ith the im plem entation o f ALS and VSI.
R E SU L T S
A lcoh ol-in volved crashes.
In each o f the five years p rio r to the in troduction o f A LS and V SI, an average o f 37 d rivers
w ith positive B A C s d ied in road crashes in M anitoba. Since 1989 (w hen A LS and V SI w ere
in troduced) the num ber o f d rinking driver fatalities has decreased to an average o f 27 per year
— a reduction o f 27% (p< .05). O ver the sam e period o f tim e, the to tal n um ber o f d river
fatalities in M anitoba increased by 9% . C om parab le data from Saskatchew an reveal an
average annual reduction in alcohol-related d river fatalities o f 33% — from 52 per year p rio r
to 1990 to 35 afterw ards (p< .05). H ow ever, the reduction in alcoho l-related fa ta lities in
S askatchew an occurred against a background o f a 9% decrease in total d river fatalities.
The m onthly num bers o f d rinking driver fatalities in M anitoba w ere subjected to tim e series
in terven tion analysis. A uto-regressive integrated m oving average (A R IM A ) m odels w ere
developed fo r th is series using the iterative iden tifica tion , estim ation and d iagnosis strategy
outlined by M cC leary and H ay (1980). A step function was added to the m odel to estim ate
the m agnitude and d irection o f the in terruption in the series associated w ith the in troduc tion
o f the A LS and VSI program s. S tatistical m odeling o f the series w ith the inclusion o f the
in terven tion param eter revealed a significant effect o f the in terven tion (p< .05). In an analysis
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o f the com parab le data from Saskatchew an, the in terven tion param eter w as not sta tistically
sign ifican t (p > .l) .
T o illustrate the change in d rinking driver fatalities associated w ith the in troduction o f the
ALS and V SI program s, tim e series analysis w as used to predict the num ber o f drink ing
driver fatalities tha t w ould have been expected in the absence o f the tw o program s. F igure 1
p lo ts the actual num ber o f drink ing d river fatalities in M anitoba from 1985 th rough 1995
(represen ted by the so lid line) along w ith the pred icted num ber o f fatalities from 1990
th rough 1995 (represen ted by the thin line). T he effect o f the in terven tion is eviden t as the
d ifference betw een the actual and pred icted values. F or m ost m onths, the p red ic ted num ber o f
fatalities exceeds the actual num ber by a considerab le m argin.
F igu re 1 : A ctu al and pred icted m onth ly n um ber o f d rin k ing driver fa ta lities in
M an itoba
R epeat D W I con victions.
D eterrence theory w ould p red ic t that the certain ty and sw iftness w ith w hich A LS is applied
should serve to reduce the likelihood o f o ffenders repeating the o ffence. T o test this
hypothesis, d river records w ere used to com pare the incidence o f repeat D W I offences am ong
a g roup o f over 18,000 D W I offenders charged prio r to the im plem entation o f A LS and a
g roup o f over 16,000 D W I o ffenders charged after A LS. F igure 2 illustrates the d ifference in
the surv ival p robab ility betw een the tw o groups up to 60 m onths after the initial offence.
O ffenders charged w ith D W I after A LS w as introduced had a sign ifican tly h igher survival
p robab ility than o ffenders w ho w ere charged p rio r to A LS. S ixty m onths after the in itial D W I
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offence the probab ility o f not being reconvicted o f D W I w as 0 .87 (± .006) am ong o ffenders
charged after A LS and 0 .74 (± .006) am ong offenders charged p rio r to A LS.
cu
T im e to con viction .
In M anitoba, as in the rest o f C anada, a D W I conviction carries a m andatory period o f licence
suspension. P rio r to the in troduction o f A L S, D W I offenders w ould often attem pt to delay
their tria l o r court date as a m eans to avoid serving the m andatory 6-m onth licence suspension
fo r D W I at a specific tim e o f year (e.g ., during a period o f seasonal em ploym ent). M any
w ould p lead not gu ilty and w ait fo r a trial in the hope o f successfu lly defeating the charge.
W ith the in troduction o f the im m ediate 90-day adm inistrative suspension, the tactic o f
delaying court dates p roved to be counterproductive as it only served to increase the total
period o f suspension. A n early court date w ould allow the adm in istrative suspension to be
served concurren tly w ith the m andatory suspension fo r a D W I conviction . A s a resu lt o f A LS,
it becam e advantageous for o ffenders to plead guilty as soon as possib le after the o ffence to
m in im ize the total tim e o f suspension. H ence, it m ight be expected that the elapsed tim e
betw een offence and conviction in court w ould decrease as a result o f ALS.
A s expected , the average elapsed tim e betw een the date o f offence and the date o f conviction
w as signficantly longer fo r o ffenders charged before com pared to after the in troduc tion o f
A L S. In fact, the elapsed tim e betw een offence and conviction decreased by alm ost 50% —
from an average o f 117 days p rio r to A LS to 62 days afterw ards (p c .0 0 1 ). F o r com parison ,
the decrease in the elapsed tim e betw een offence and conviction for D W I o ffenders in
S askatchew an in the sam e tim e period w as only 13% — from 91 days to 79 days (p< .05).
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R epeat D W S convictions.
D eterrence theory w ould also predict that vehicle im poundm ent w ould have a significant
im pact on reducing the num ber o f reconvictions fo r driv ing w hile suspended (D W S). D river
records from approxim ately 7 ,700 persons convicted o f D W S prio r to V SI and 6 ,200 persons
convicted o f DW S after the im plem entation o f V SI reveal a significan tly h igher survival
p robability am ong the post-V SI group. F igure 3 illustrates the d ifference in survival
p robability betw een those convicted before (represented by the th ick line) and after the
im plem entation o f V SI (represented by the thin line). A fter 48 m onths, the survival
probab ility o f the post-V SI g roup w as 0.73 (± .012) com pared to 0 .54 (± .011) am ong the
pre-V SI group.
ro
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D IS C U S S IO N
T he resu lts o f th is study contribute to the body o"f litera ture show ing bo th general and specific
deterren t effects o f A LS. In particular, after the in troduction o f A LS in M anitoba there w as a
significant decrease in the num ber o f fatally in jured drink ing drivers. T his effec t does not
appear to have been a short-term , tem porary im pact that d issipated over tim e. R ather, the
im pact has been sustained over at least a six -year period.
T he observed reduction in a lcohol-involved driver fatalities can not, how ever, be attribu ted
entirely to the in troduction o f A LS. G iven that V SI w as in troduced at the sam e tim e as A L S,
it is conceivab le that the observed effect w as a result o f the separa te as w ell as the com bined
influence o f the tw o program s. It w as also noted that S askatchew an also experien ced a
substantial reduction in drink ing d river fatalities over the sam e period o f tim e. In fact,
drink ing driver fatalities have been generally decreasing in all ju risd ic tions in C anada. T he
decrease in M anitoba, how ever, occurred at a tim e during w hich the overall num ber o f d river
fatalities w as increasing . T he net decrease in drink ing d river fatalities in M anitoba , therefo re ,
w as larger than in Saskatchew an.
T he data on repeat D W I convictions prov ide com pelling ev idence o f the specific deterren t
effect o f A LS. T he survival p robability o f D W I offenders subjected to im m ediate 90-day
licence suspension w as significantly h igher than am ong offenders charged p rio r to the
in troduction o f A LS. U p to five years later, o ffenders subjected to A LS w ere significantly
less likely to be reconvicted o f D W I than o ffenders not subjected to A LS.
O ther facto rs m ay, how ever, have con tribu ted to the observed effects. P rom inen t am ong such
facto rs w as the in troduction o f a m andatory assessm ent and rehab ilita tion p rog ram fo r all
D W I offenders in 1987. A lthough introduced tw o years p rio r to A L S, the po ten tia l im pact o f
such a p rogram should not be overlooked.
F rom an adm in istrative perspective, the in troduction o f A LS has served to reduce the back log
o f D W I cases aw aiting trial in court. T he average elapsed tim e betw een offence and
conv iction has been reduced by half. A lthough it m ight be argued that the im m ediacy o f A LS
is coercing som e o ffenders into pleading guilty w ho m ight have a legitim ate defence against
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the charges, it cou ld also be argued that the sw ift adm in istration o f ju stice is o f greater
benefit, not only from the perspective o f deterrence but also from that o f rehab ilita tion . F or
exam ple, a shorter delay betw een offence and conviction can assist in getting o ffenders into
the D W I assessm ent and trea tm ent program sooner.
The analysis o f repeat D W S convictions also revealed a substantial im pact o f V SI. U p to four
years later, persons convicted o f D W S after the in troduction o f V SI w ere sign ifican tly less
likely to be reconvicted o f DW S than drivers convicted o f DW S but not subjected to vehicle
im poundm ent.
In conclusion , the A LS and V SI p rogram s have had a substantial im pact on d rink ing and
d riv ing and driv ing w hile suspended in M anitoba. T hese effects appear to be largely the result
o f the im pact these p rog ram s have had on persons d irectly affected by them — i.e., specific
deterrence. T he sanctions associated w ith A LS and V SI are sw ift, sure, and severe — key
ingred ien ts in effec ting change am ong offenders.
R E F E R E N C E S
M cC leary , R. A nd H ay, R .A . (1980) Applied Time Series Analysis fo r the Social Sciences.
B everly H ills: Sage.
Ross, H .L . (1991). Administrative Licence Revocation fo r Drunk Drivers: Options and
Choices in Three States. W ash ing ton , D .C .: A A A Foundation fo r T raffic Safety.
S tew art, K ., G ruenew ald , P ., and Roth, T. (1989) An Evaluation o f Administrative P er Se
Laws. F inal report on g ran t 86-IJ-C X -0081. W ash ing ton , DC: N ational Institu te o f Justice.
W illiam s, A .F ., W einberg , K., and F ields, M. (1991) T he effectiveness o f adm in istrative
license suspension law s. Alcohol. Drugs and Driving 7 (1): 55-62.
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