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Effect of ALS Law
This section evaluates the impact of the ALS law on DUI and moving traffic offenses and crashes of first and multiple DUI offenders.
The previous section demonstrated that before implementing the ALS law in September 1993, many drivers arrested for DUI escaped license suspension. Even for those who received this sanction, there was frequently a delay of up to 6 months after the impaired driving arrest before their licenses were suspended. Implementation of the ALS law clearly changed this situation. After September 1993, 95% of both first and multiple DUI arrestees received a license suspension beginning on the day of apprehension, and 99% were ultimately suspended (see Figure II-1). This section reports on a study using survival analysis to determine the specific deterrent effect of the ALS law on DUI offenses, moving citations, and crashes of first and multiple DUI offenders.
A major reason most proponents have supported enacting an ALS law is for its general deterrent effect on the driving public as a whole rather than simply its specific incapacitation effect on DUI offenders. Both the studies by Klein (1989) and Zador, Lund, Fields, and Weinberg (1988) demonstrated such a general deterrent effect in statewide alcohol-related fatal crash reductions in States enacting ALS laws. This report does not assess the general deterrent effect of the combined ALS and VA laws. The data set used for this study is limited to drivers committing DUI offenses between September 1, 1990, and August 30, 1995, and does not include information on total alcohol-related crashes for the State during that period.
Evaluation of the effect of the ALS law on offenses by convicted DUI drivers required a comparison of recidivism rates before and after implementing the law. Therefore, for this study, it was established that no other important changes in the law or criminal justice procedures that might effect recidivism rates were made. Three potentially confounding factors were identified that might contribute to differences in recidivism before versus after September 1993. First was the level of DUI enforcement. Second was a proposed change in the locus of adjudication of multiple DUI offenders. Third was a related piece of legislation: a new subsection to Ohio House Bill 377, implemented on September 30, 1993, that enabled the Court to add a 3 months of suspension to the 3 months ALS suspension for first DUI offenders, for a total of 6 months suspension. Suspension time for third DUI offenders was also lengthened from 1 to 2 years.
As noted in Section I, all (58,490) DUI or implied consent convictions were extracted from the Ohio BMV between September 1990 and August 1995 for this study. The trend over those 60 months in statewide total monthly DUI convictions is shown in Figure III-1. There is a significant drop in the total DUI convictions between 1990 and 1993 (when monthly DUI convictions were between 1,000 and 1,300) and in the 2 years after implementing the ALS and VA laws (when DUI monthly convictions were between 700 to 900). The question posed for the present research is "Does this change represent a reduction in the level of DUI enforcement effort or a change in the proportion of arrested drivers convicted by the courts?" Alternatively, "Can this be attributed to a reduction in impaired driving by drivers affected by the new law?"
A partial answer to this question is provided by Figures III-2 and III-3, which show the number of arrests for drivers without a previous DUI separately from arrests of drivers with one or more prior offenses. The two series show distinctive trends, with respect to the time when the new laws were implemented in the fall of 1993. The trend in arrests of new offenders without a prior offense shows a long-term downward trend over the 5 years of data displayed. There is no indication of change when the new laws were implemented as is confirmed by the data shown in Table III-1. The time series analysis using an interrupt at September 1, 1993, shows no indication of a significant change for these first-time offenders associated with the new legislation.
The lack of change in the first-time DUI offender monthly trend provides evidence that the enforcement level and the conviction rate for DUI offenders did not change significantly at the time that the ALS and VA laws were implemented. The incapacitation effect of the ALS suspension occurs only after the individual has been apprehended. Similarly, the VA law affected only offenders who were already suspended because of a prior DUI or who were convicted of a second impaired driving offense. Only the general deterrent effect (that is, the fear of immediate loss of license) inherent in the ALS law would be expected to effect drinking drivers who have not yet committed a DUI offense. This lack of change suggests that the new laws did not have a major general deterrent effect on impaired driving by the public as a whole. However, this cannot be determined from the present data that include only the records of DUI offenders. Alcohol-related crashes of drivers without DUIs in the general public may have been reduced following the ALS and VA laws.
The monthly conviction totals for drivers with one or more DUI offenses in Figure III-3 shows a distinctly different trend. It rises during the 3 years (between September 1990 and August 1993) before implementing the new laws, and then falls sharply after the fall of 1993. The increased incapacitation sanctions of the license suspension and vehicle immobilization laws applied to these multiple offenders. Multiple offenders also showed a significant reduction in monthly DUI offenses when the new laws were implemented. This change is not likely to have been caused by a change in enforcement or in court procedures as shown by the lack of change in the level of apprehension and prosecution of first-time offenders.
The new ALS and VA laws also changed the venue for adjudication of multiple DUI offenders that could account for some of the decrease after September 1993. For example, one element of the new legislative no longer allowed the Mayors Courts (lower courts) in Ohio to handle multiple DUI offenders. This change would be expected to result in a drop in the number of multiple offender prosecutions in the Mayors Courts after September 1, 1993, and, consequently, an increase in such prosecutions in the Municipal Courts (higher courts). Another possibility is that cases could be delayed or plea bargained to a lessor offense in the process. If this occurred, it might account for an apparent decline in multiple DUI cases.
Fortunately, the State driver record data identified which Court adjudicated the DUI conviction. By using these data, it was possible to study the trend in multiple DUI convictions in both types of courts before and after September 1, 1993. As shown in Figure III-4 and Table III-2, during the 2 years from September 1993 to August 1995, there was only a marginal, insignificant drop in the number of multiple DUI cases heard in the Mayors Courts. At the same time, the Municipal Courts, which should have shown an increase in multiple DUI cases, actually showed a significant drop in adjudicating multiple DUI cases. This suggests that the transfer of cases from the Mayors Courts to the Municipal Courts did not effect the number of multiple DUI convictions from September 1, 1993, to August 30, 1995, the period covered by this study.
In addition to providing for a 3-month administrative license suspension for first DUI offenses, a follow-up House Bill 377 (effective September 30, 1993) allowed judges to suspend the licenses of first-time offenders for 90 days up to a minimum of 6 months if convicted. Effectively, this allowed the court to add a 3-month license suspension to the automatic 90-day suspension that first offenders received under the new ALS law, thus doubling the suspension period to 6 months. The length of the suspension period for second, third, and fourth DUI offenders did not change as a result of the ALS law; however, the length of suspension for third offenders was lengthened from 1 to 2 years.
To measure the effect of the ALS law on the driving records of DUI offenders, the period beginning with DUI arrest and ending up to 2 years following arrest was compared for offenders arrested between 1990 and 1993 (the period before the ALS law) and September 1993 to August 30, 1995 (the period following the implementation of the ALS law). To help separate the effects of the ALS law from the effects of the VA law, first offense DUIs who were incapacitated only by the ALS law were analyzed separately from multiple offenders affected by both laws. Kaplan-Meier survival analysis, the most effective method for comparing reoffense rates before and after implementing the ALS and VA laws, was used.
Figure III-5 and Table III-3 provide separate survival curves and results of the Tarone-Ware Survival Analysis for individuals with one DUI offense and those with two or more DUI offenses before and after the law. From 1990 to 1993, first DUI offenders demonstrated an approximate 15% attrition rate during the 24 months following their arrest. After implementation of the ALS law, this attrition rate was reduced by almost two-thirds, 5% over 24 months. The probability that such a large change could occur by chance is less than one in one thousand. For multiple offenders, the change was even greater. Before the law, during the 2 years following arrest, multiple offenders had a DUI recidivism rate of 25%. This was reduced to 7% after implementation of the ALS law. The curves in Figure III-5 show that before the ALS law was implemented, relatively large numbers of first and multiple offenders committed other offenses in the 6 months between the arrest and the court conviction for the DUI offense. During this period, many of those who were ultimately suspended remained fully licensed and free to drive (see Figure II-4). This freedom to continue to drive apparently resulted in high DUI reoffense rates. Following application of the ALS law when the license was suspended on the day of arrest, this early drop in the survival rate disappears for both the first and multiple offenders, and reoffenses occur more gradually over 2 years.
The issue arises as to whether the difference between the before and after recidivism records is accounted for principally by this early 6-month period during which, before the law, most offenders were free to drive or whether, if one considers only the period following the initial 6 months, there is still a significant difference in recidivism rates. Figure III-5 shows that in the period beyond the initial 6 months, the curves for the "before" and "after" groups continue to diverge. A test of the significance of the differences in survival rates after the initial 6 months was done using the Kaplan-Meier analysis procedure. It demonstrated that the ALS and VA laws resulted in lower recidivism during this 6- to 24-month postperiod after these laws were implemented.
The driving records of DUI offenders apprehended before and after the ALS and VA laws were also examined to determine whether the change in the timing and comprehensiveness of suspension impacted the numbers of moving violations committed by DUI offenders. Figure III-6 provides survival curves for first and multiple offenders before and after implementing the new laws in September 1993. Before, 20% of first DUI offenders had a moving violation on their records during the 24 months following their DUI arrest. After, only 9% of first offenders were cited for a moving violation within 24 months of their DUI arrest. For multiple offenders, the moving violation rate in the 24 months following arrest before the law was 28% compared to 15% after implementing the ALS and VA laws. The Tarone-Ware Survival Analysis procedure demonstrated that these differences were statistically significant beyond the one in one thousand level (see Table III-5).
In addition to moving violations, the records of individuals committing DUI offenses before and after implementing the new laws were also examined to determine the number of crash involvements during the 2 years following the initial DUI arrest. Figure III-7 presents the survival curves for crash involvement for offenders apprehended before and after September 1993. Before the law, 12% of first offenders and 14% of repeat offenders were involved in crashes during the 2 years following their DUI offense. After September 1993, only 5% of first offenders and 7% of repeat offenders were involved in crashes during that period. Once again, these differences were highly significant based on the Tarone-Ware Survival Analysis with the probability of such differences being found by chance being less than one in one thousand (see Table III-6).
This section has demonstrated that DUI recidivism, moving violation rates, and crash involvements decreased for DUI offenders after implementing Ohios ALS and VA laws. These relative decreases were quite large, running from one-third to two-thirds of the prelaw rates. In every comparison, the reduction in the offense or crash rate is significant at beyond the one in one thousand level. The offense and crash reductions observed for first DUI offenders can probably be attributed principally to the ALS law because the VA law did not apply to first DUI offenders. However, the VA law may have had some effect on these first offenders based on their perceived risk of having their vehicles impounded if they received a second DUI or were apprehended driving while suspended. The proportions of offense and crash reductions for multiple offenders were slightly larger, perhaps because these offenders were subject to the VA law as well as the ALS law. For neither first nor multiple offenders is it possible to completely separate the effects of the two laws.
In comparing the attrition rates for DUI offenses with the rates for moving violations and crashes (see Figures III-5, III-7, and III-8), multiple offenders have lower DUI survival rates but higher moving violation and crash survival rates than first offenders. This is probably a reflection of the more severe drinking problem status of the multiple DUI offenders that makes DUI offenses more likely. Moving violations and crashes, on the other hand, are a more direct result of driving exposure. Since first offenders were suspended for a shorter period and were not affected by the VA law, some were probably reinstated and, thus, were free to drive more than multiple offenders in the 2 years following their DUI arrest.
The ALS law moved the date of suspension forward for these offenders and reduced from 15% to less than 2% the proportion remaining unsuspended at the end of 2 years. However, as described in the following sections, the VA law was also applied at the time of arrest. The vehicle was seized and held for a minimum of 5 days pending a hearing. Further, the vehicle could continue to be held under the VA law until a trial. The results indicate that the VA law had an effect on recidivism of the multiple offenders who received the sanction. However, only some offenders who were eligible for sanction actually had their vehicles impounded or immobilized. An important factor in considering the evidence in Section V on the effectiveness of vehicle immobilization is that all multiple offenders receiving that sanction had suspended licenses because the minimum suspension for multiple offenses was 1 year. Further, after implementing the new laws, 98% of multiple offenders received that suspension. The vehicle sanction, 90 to 180 days for DUI offenders, occurred within the 1-year suspension, so this penalty was in addition to the suspension imposed under the ALS law.