Underreporting of driver alcohol involvement in United States police and hospital records: Capture-recapture estimates

Underreporting of Driver Alcohol Involvement in United States Police and Hospital Records: Capture-Recapture Estimates

Ted R. Miller, Rekaya Gibson, Eduard Zaloshnja Pacific Institute for Research & Evaluation

Lawrence J. Blincoe, John Kindelberger, Alexander Strashny U.S. National Highway Traffic Safety Administration

Andrea Thomas University of Utah

Shiu Ho University of Maryland Baltimore

Michael Bauer, Sarah Sperry New York State Department of Health

Justin Peng Connecticut Department of Public Health

Mike Singleton University of Kentucky

Tracy J. Smith South Carolina State Budget and Control Board

Ying Zhang Nebraska Department of Health and Human Services

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ABSTRACT – This paper analyzes what portion of US nonfatal crashes are alcohol-involved and how well police and hospitals detect involvement. A capture recapture model estimated alcohol involvement from levels detected by police and hospitals and the extent of detection overlap. We analyzed 550,933 Crash Outcome Data Evaluation System driver records from 2006-2008 police crash report censuses probabilistically linked to hospital inpatient and emergency department (ED) discharge censuses for CT, KY (admissions only), MD, NE, NY, SC, and UT. We computed national estimates from NHTSA’s General Estimates System. Nationally an estimated 7.5% of drivers in nonfatal crashes and 12.9% of nonfatal crashes were alcohol-involved. (Crashes often involve multiple drivers but rarely are two alcohol-involved.) Police correctly identified an estimated 32% of alcohol-involved drivers in non-fatal crashes including 48% in injury crashes. Excluding KY, police in the six states reported 47% of alcohol involvement for cases treated in EDs and released and 39% for admitted cases. In contrast, hospitals reported 28% of involvement for ED cases and 51% for admitted cases. Underreporting varied widely between states. Police reported alcohol involvement for 44% of those who hospitals reported were alcohol-involved, while hospitals reported alcohol involvement for 33% of those who police reported were alcohol-involved. Police alcohol reporting completeness rose with police-reported driver injury severity. At least one system reported 62% of alcohol involvement. Police and hospitals need to communicate better about alcohol involvement. Despite the proven effectiveness of brief alcohol intervention, EDs rarely detect, much less intervene with crash-involved drinking drivers. Both police and EDs particularly need to assess alcohol involvement in minor injury better.

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INTRODUCTION

Police underreport alcohol involvement in crashes (Terhune and Fell 1981, Maull et al. 1984,

Dischinger and Cowley 1989, Soderstrom, Birschbach and Dischinger 1990, Blincoe, Seay, Zaloshnja, et al. 2002, Guo, Eskridge, Christensen, et

56th AAAM Annual Conference

Annals of Advances in Automotive Medicine October 14‐17, 2012

Vol 56 • October 2012

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CORRESPONDING AUTHOR: Ted R Miller, Ph.D., Pacific Institute for Research & Evaluation, 11720 Beltsville Drive, Suite 900, Calverton, MD 20705, USA; Email: [email protected]

al. 2007). Reasons include police priority on assuring safety at the crash site over determining driver alcohol involvement, expense of universal driver testing, challenges with testing seriously injured drivers and with evidentiary testing at crash scenes, and driver flight. Emergency departments (EDs) also often do not test or report alcohol involvement of injured drivers in crashes. Reasons include time and resource constraints in busy EDs; testing expense; and concerns that charting alcohol involvement would allow health insurers to deny coverage, divert doctors from treating patients to testifying in criminal and liability cases, require alcohol interventions that attending physicians are uncomfortable delivering or perceive as lacking effectiveness, or raise patient confidentiality issues (Chezem 2004/2005, D’Onofrio and Degutis 2004/2005).

Estimating the impaired driving crash count from crash data requires adjusting for underreporting. Measuring the burden of alcohol, comparing burden between states, and evaluating impaired driving interventions require understanding how extensive and variable underreporting is.

This article answers several relevant questions. What portion of injury crashes is alcohol-involved? How well do United States police and medical systems capture this information? How does reporting vary between states?

We address these questions with linked multi-state police and hospital data on crash-involved drivers treated at hospitals. These two linked, yet independent sources each assess alcohol involvement in some crashes. We used a capture-recapture statistical model (Chapman 1951) to estimate unreported cases from the extent of reporting overlap.

METHODS

Data Sources

State Crash Outcome Data Evaluation System (CODES) data sets link existing police crash report and hospital injury discharge censuses. The National Highway Traffic Safety Administration (NHTSA) funds 15 state CODES projects. We contacted these states to determine if their data would support alcohol

reporting rate estimation. Connecticut (CT),

Kentucky (KY), Maryland (MD), Nebraska (NE), New York (NY), South Carolina (SC ), and Utah (UT) had usable probabilistically linked data on admitted cases. All these states except KY also had linked ED discharge data. All linked cases included Maximum Abbreviated Injury Score (MAIS, AAAM 1990) coded using ICDmap90 (MacKenzie and Sacco 1997) and police-reported injury severity (A=Incapacitating (Serious) Injury, B=Non-Incapacitating (Evident or Visible) Injury, C=Possible Injury, O=No Injury). We pooled 2006-08 data from all states except KY and SC which lacked 2008 data. For balance, we weighted the data from those two states upward by a factor of 1.5.

Participating CODES sites already had linked crash and hospital data in accordance with current CODES standards. During probabilistic linkage, sites performed multiple imputations of missing links between crash and hospital data. The process uses match probabilities to generate representative sets of imputed linked record pairs (McGlincy 2004).

We specified uniform data processing rules. These included: (1) capture only records that police indicated were for drivers, (2) select linked live inpatient discharges excluding readmissions and (3) select linked live ED discharges including those transferred to another short-term hospital or long-term non-psychiatric care facility but excluding admissions through the ED (cases that also appear in the admissions data and would be double-counted). We excluded fatalities because NHTSA already estimates alcohol involvement in all fatal crashes.

We defined hospital coding as alcohol-involved if the discharge record included any acute or sub-acute alcohol diagnosis listed in Table 1. Some listed diagnoses are subacute rather than acute. Subacute conditions generally are diagnosed in a hospital setting only if a patient goes into alcohol withdrawal. Withdrawal implies the patient was alcohol-positive when admitted. All records included diagnoses. We defined police coding as alcohol-involved if the police report included a positive BAC level, a citation for driving under the influence (DUI), or a checkbox indicating the driver had been drinking. Thus we coded cases where police did not complete the alcohol questions as uninvolved. We excluded cases police reported as drug- but not alcohol-involved.

Tabular and Statistical Analysis

We estimated the percentage of driver alcohol involvement captured in police and hospital records. Applying those estimates to national police report

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data, we then estimated alcohol-involvement in all US crashes.

Capture of Alcohol Involvement

NHTSA’s CODES Technical Resource Center at the University of Utah received and tabulated de-identified, linked records based on a standardized data element model. By state and pooled across states, they tabulated how many records indicated alcohol involvement according to police, hospitals, and both sources. They included crosstabs by level of treatment (inpatient vs. ED) and severity, tabulating both MAIS and police-reported severity.

We used a capture recapture model (which is based on Bayesian inference) to estimate alcohol involvement from involvement levels detected by the police and hospital systems and the extent of detection overlap. By crash severity and for all nonfatal crashes combined, we performed these calculations by state and across the six states.

More than a century ago, Petersen (1896) used a capture-recapture model to estimate wildlife population sizes when a subset of the population was marked and released. By resampling the population a short time later (to avoid complexities associated with births and deaths) and seeing what portion of the second sample came from the first sample, biologists began estimating total populations. Subsequently these models became a standard epidemiological tool for estimating disease incidence when two surveillance systems existed. They increasingly are used to estimate crash and injury incidence (Thomas et al. in press; Hassel, Asbjørnslett and Hole 2011).

We applied two-sample capture-recapture formulas to estimate a case count and its standard error from two independent assessments of the same population. Specifically, we estimated number of alcohol-positive drivers from contemporaneous but independent police and hospital capture of alcohol involvement in a group of crash-involved drivers.

In Chapman’s (1951) capture-recapture model, m = cases alcohol-involved in police records, n = cases alcohol-involved in hospital records, and B = cases alcohol-involved in both systems. The capture-recapture formula is: Number alcohol-involved = (m+1) * (n+1) / (B+1), with the estimated count constrained to not exceed total linked cases. This formula provides an unbiased estimator for two independent samples.

The corresponding standard error (SE) formula is:

SE = sqrt (m * m * (n+1) * (n-B) / ((B+1) * (B+1) * (B+2)). The percentage alcohol-involved is the number alcohol involved / total linked cases.

National Estimates

To estimate the number of alcohol-involved drivers nationally, we started with weighted counts of drivers by police-reported injury severity and alcohol involvement from NHTSA’s General Estimates System (GES). We reclassified cases that were unknown if injured or with unknown injury severity into ABCO categories in proportion to cases with known severity. We divided the resulting alcohol-involved driver counts by police-reported ABCO severity by corresponding six-state rates of alcohol underreporting.

This procedure assumes comparable alcohol involvement in linked and unlinked cases. To test that assumption, we compared alcohol involvement nationally and in the linked state data. We used the national ABCO incidence distribution to collapse six-state involvement into ABC and ABCO groupings.

Crashes often involve more than one driver. If any driver is alcohol-involved, the crash is alcohol-involved. That means the percentage alcohol-involved is much higher for crashes than for drivers in crashes. Tabulating 2010 GES data, a typical crash involves 1.82 drivers but a typical alcohol-involved crash involves only 1.0 drinking drivers. To estimate crash-level alcohol involvement, we multiplied estimated driver-level involvement by ABCO severity by the corresponding GES ratios of crash involvement to driver involvement. This is equivalent to dividing police-reported crash alcohol involvement rates by underreporting rates from the driver analysis. It assumes the ratio of alcohol-involved crashes by severity to alcohol-involved drivers with injuries of that severity does not vary with police reporting of alcohol.

RESULTS

We had 550,933 linked driver records from nonfatal crashes. Table 2 shows the pooled seven-state counts by reported alcohol involvement, driver injury severity, and place of treatment. (Recall that for balance Table 2 weights KY and SC cases by 1.5, yielding 580,878 weighted cases.) We entered these data and similar data by state into the capture-recapture equation. Police-reported 17,406 drivers (3.0%) as alcohol-involved. Hospitals recorded 12,929 drivers (2.2%) as alcohol-involved. Non-overlap was the norm; only 5,663 (3,235 + 1,759) drivers were reported as alcohol-involved in both


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systems. Police only reported alcohol involvement in 44% (5,663/12,929) of cases hospitals reported as alcohol-involved. Hospitals reported alcohol involvement in only 33% (5,663/17,406) of cases police reported as alcohol-involved. At least one system reported 24,672 injured drivers (17,406 + 12,929 – 5,663) as alcohol-involved.

Tables 3 and 4 summarize the multi-state capture-recapture estimates by place of treatment and total. To capture a broader spectrum of treatment, we focus on results for the six states with ED data.

Excluding KY, an estimated 6.8% of drivers hospital-treated for nonfatal crash injuries were alcohol-involved. Together the two systems reported 62% of alcohol involvement (not tabulated). Police, however, reported only 44% of alcohol involvement and hospitals only 33%. Police reports included 47% of involvement for cases treated in the ED and released and 39% for admitted cases. In contrast, the medical system reported 27% of involvement for ED cases and 51% for admitted cases. Weighting the CODES estimates by severity using the national driver ABCO distribution from GES, police correctly identified only 32% of alcohol-involved drivers in non-fatal crashes including 48% in ABC-injury crashes.

Police-reported capture of alcohol involvement was much lower for hospital-treated drivers who police reported as uninjured (27% reported) than for ones reported as injured (47% reported). Completeness of police alcohol reporting rose with police-reported driver injury severity. Supporting that finding, NHTSA estimates that police capture 65.5% of driver alcohol involvement in fatal crashes (National Center for Statistics and Analysis 2012, NHTSA 2012).

Underreporting of alcohol was lowest for uninjured to moderately injured patients (MAIS 0-2) admitted to hospital, then rose with MAIS. Conversely, alcohol involvement reporting by EDs was more complete for MAIS 3-4 than MAIS 1-2 injuries.

Tables 5 and 6 show similar summaries by state. Reporting completeness varied widely between states. For example, police in two states reported only 25% of alcohol involvement, while police in two other states reported 75% to 82%.

Nationally, police report a higher proportion of all drivers in crashes have minor injuries and predictably a much higher proportion have no injuries than the six-state data indicate are treated by hospitals. Table 7 shows the proportions.

Overall, alcohol involvement of drivers in nonfatal crashes is 2.4% nationally and 2.3% in the linked 6-state data. However, the pattern of involvement differs. Despite the under-capture of uninjured drivers in linked data, reported alcohol involvement of uninjured drivers is similar in the two data sets (1.9% nationally versus 2.1% in the linked data). Involvement rates for A and B injuries are much higher nationally than in the linked CODES data.

The 6-state capture-recapture estimate of 6.8% driver alcohol involvement equates to 12.4% of crashes alcohol involved in 2006-08. Nationwide, we estimate 7.5% of drivers and 12.9% of crashes were alcohol-involved in 2010 (Table 8). This includes 13.1% of O (property damage only) crashes, 8.4% of C (possible injury) crashes, 16.7% of B (visible injury) crashes, and 22.6% of A (serious injury) crashes. NHTSA estimates 26.9% of drivers in fatal crashes and 38.3% of fatal crashes were alcohol-involved in 2010 (National Center for Statistics and Analysis 2012, NHTSA 2012). Figure 1 summarizes police-reported and total estimated involvement.

Maryland’s Shock Trauma Center provided supplemental data for 2007-08. They tested 97.6% of drivers in crashes admitted during that time period. Of alcohol-positive drivers, 83.7% had BACs above the .08 legal limit including 89.9% of those who police indicated were alcohol-involved and 75.5% of those without a police indication. (Similarly, National Center for Statistics and Analysis (2012) estimates 81.1% (9,694/11,948) of alcohol-positive drivers in fatal crashes have BACs above .08.) If these percentages held nationwide, 6.0% of drivers in nonfatal crashes (0.899 * 2.4% + 0.755 * (7.5%-2.4%)) would have BACs above .08. By the time Shock Trauma drew blood for testing, 9% of those the police coded as alcohol-involved were BAC-negative (but possibly drug positive). Of those with positive BACs, police did not record alcohol involvement for 42% including 39% of those above .08 and 65% with lower BACs.

DISCUSSION

Previously police underreporting of alcohol involvement in nonfatal crashes was judged using linkage studies from individual hospitals with research-oriented physicians. Our data are far more representative and recent then prior estimates. Studies from the 1980s to early 1990s suggested police correctly identified 27% of alcohol-involved crashes with nonfatal injury; they correctly identified 46% in Maryland in 1999-2000 (Blincoe et al. 2002). Our 44% estimate for hospital-treated drivers is consistent with Maryland’s estimate.


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Among our 6 states with ED data, police reported 2.3% of drivers as alcohol involved. National average involvement was 2.4% (tabulated from GES 2010 data). Using our underreporting adjustments by ABCO severity, 7.5% of drivers were alcohol-involved nationally compared to 6.8% in the 6 states, with a range of 4.7% to 9.0% between states. In aggregate then, impaired driving is reasonably similar in our 6 states and nationally. Involvement also was similar for drivers police coded as uninjured (O) nationally and in the 6-state hospital-treated data.

Limitations and Strengths

We analyzed overlap in alcohol reporting but police legitimately may not report alcohol involvement at legal levels. Shock Trauma and NHTSA data suggest this could account for 25% of police underreporting. Coding errors, missing data, and non-uniformity of administrative data sets impose further limitations. Only SC and UT crash reports integrated BAC test results, and SC alcohol coding relied exclusively on testing. We may have removed a few alcohol-involved cases that police misreported as drug involved. Furthermore, CODES linkages are probabilistic. The occasional mismatch reduces reporting consistency and capture-recapture accuracy.

Although police-reported injury severity is widely used, hospitals’ MAIS severity codes are much more accurate. Police coders often have little contact with drivers transported from crash scenes.

Multiplication of KY and SC counts by 1.5 was an arbitrary way to balance the sample. balanced the sample. We did not assess accuracy of alcohol reporting for non-occupants. A parallel non-occupant assessment is desirable. An assessment of underreporting in crashes where drivers are uninjured would be desirable as well, but no data sets exist to support a reliable estimate. Finally, assessing alcohol involvement for hospital-treated drivers without a linkable police report might yield insight into hit-and-run crashes and unreported single vehicle crashes.

Despite its limitations, this is by far the largest and most geographically representative assessment of alcohol underreporting by police and hospitals. Indeed it may be the first broad-based assessment of ED and inpatient underreporting. Capture-recapture modeling also greatly improved its accuracy.

Policy Implications

Wide variation in underreporting between states raises questions about efforts to estimate impaired driving incidence and cost by state. Applying average

underreporting rates from this six-state sample to state-reported counts of alcohol-involved crashes will not yield very reliable estimates of total crashes. That means our national estimate has wide uncertainty.

It is well-established that alcohol makes it harder to assess and manage injury patients (Center for Substance Abuse Treatment 1995). Thus failure to detect and chart alcohol involvement in half of admitted drivers suggests these trauma patients may get suboptimal care. EDs also should be encouraged to probe alcohol involvement of more drivers, especially those who suffered minor to moderate injuries. Our estimates suggest that despite demonstrations of the effectiveness of brief alcohol interventions in the ED (Academic ED SBIRT Research Collaborative 2010), hospitals do not detect, much less intervene with most crash-involved drinking drivers.

Police crash reports often miss alcohol involvement. Extensive undercounting suggests reporters especially need to probe alcohol involvement of more drivers they suspect were uninjured.

We observed large non-overlap in reporting between police and hospital systems. Police reported alcohol involvement for 44% of those who hospitals reported were alcohol-involved, while hospitals reported involvement for 33% of those who police reported were involved. The two systems need to communicate better about alcohol involvement. Advancing wireless technologies might support real-time integration of police crash reports with EMS run reports or electronic health records; integrated capture would have detected 62% of involvement.

CONCLUSION

In 6 geographically spread states, 6.8% of drivers hospital-treated for injury were alcohol-involved in 2006-2008. If underreporting in those states is typical, 12.9% of nonfatal crashes nationwide and 7.5% of drivers in nonfatal crashes were alcohol-involved in 2010.

Underreporting of driver alcohol involvement is endemic in police and hospital systems. Better communication between the systems could reduce the problem; 62% of alcohol involvement is reported in at least one system.

ACKNOWLEDGMENTS

This work was supported in part by contracts and cooperative agreements from NHTSA and by NIAAA grant R21 AA019531-01A1. All content


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represents views of the authors but not necessarily the funding agencies.

REFERENCES

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Center for Substance Abuse Treatment. Alcohol and Other Drug Screening of Hospitalized Trauma Patients. Treatment Improvement Protocol (TIP). Series, 16. Rockville, MD: Substance Abuse and Mental Health Services Administration; 1995.

Chapman DG. Some Properties of the Hypergeometric Distribution with Applications to Zoological Sample Censuses. Berkeley, University of California Press, 1951.

Chezem L. Legal barriers to alcohol screening in emergency departments and trauma centers. Alcohol Res Health. 28: 73-79, 2004/2005.

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Hassel M, Asbjørnslett BE, Hole LP. Underreporting of maritime accidents to vessel accident databases. Accid Anal Prev, 42: 2053-2063, 2011.

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APPENDIX

Table 1. Internatonal Classification of Diseases, Ninth Edition, Clinical Modification (ICD-9-CM) Codes That Are Considered Medical Indications of Alcohol If They Appear in Any Diagnosis Field

Code Acute 790.3 Excess blood level of alcohol 980.0 Toxic effects of alcohol V70.4 Examination for medico legal reasons V79.1 Alcoholism E860.0 Alcoholic beverages E860.1 Accidental poisoning by other and

unspecified ethyl alcohol & its products


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Sub-Acute 291.0 Alcohol withdrawal delirium 291.1 Alcohol amnestic syndrome 291.2 Other alcoholic dementia 291.3 Alcohol withdrawal hallucinosis 291.4 Idiosyncratic alcohol intoxication 291.5 Alcoholic jealously 291.8 Other specified alcoholic intoxication 291.9 Unspecified alcoholic psychosis

265.2 Pellagra 303.0 Acute alcohol intoxication 303.9 Other and unspecified alcohol

dependence 305.0 Alcohol abuse 357.5 Alcoholic polyneuropathy 425.5 Alcoholic cardiomyopathy 535.5 Alcoholic gastritis

Source: Miller, Lestina, and Smith, 2001.

Table 2. Police-Reported Alcohol Involvement by Medically Indicated Alcohol Involvement, Police-Reported and MAIS Injury Severity, and Place of Treatment, 7 States, 2006-2008

Emergency Department Only Inpatient Total Medical Indication of Alcohol Medical Indication of Alcohol Involved

No Yes No Yes Police-Reported Severity Police-Reported Alcohol Involved Police

Reported O: Not Injured 3,127 535 130 134 3,926C: Possible Injury 2,874 1,234 315 332 4,754B: Non-incapacitating Injury 2,979 1,446 356 554 5,335A: Incapacitating Injury 967 555 995 873 3,390Total 9,947 3,770 1,796 1,893 17,406

Police-Reported Not Alcohol Involved Hospital Reported

O: Not Injured 178,678 1,222 5,405 550 2,441C: Possible Injury 241,472 1,419 10,944 604 3,589B: Non-incapacitating Injury 79,775 1,245 8,157 825 4,070A: Incapacitating Injury 20,673 380 11,102 1,021 2,829Total 520,598 4,266 35,608 3,000 12,929

MAIS Severity Police-Reported Alcohol Involved Police Reported

MAIS 0: Not injured 1,258 781 94 103 2,235 MAIS 1: Minor 6,959 2,352 294 367 9,972 MAIS 2: Moderate 1,514 498 602 713 3,327 MAIS 3: Serious 108 49 498 470 1,125 MAIS 4:Severe 19 10 250 208 487 MAIS 5/6: Critical/Maximum 5 0 58 21 83 Injured, Severity Unknown 1 2 0 3 6 Total 9,864 3,692 1,795 1,884 17,234

Police-Reported Not Alcohol Involved Hospital Reported

MAIS 0: Not injured 84,029 937 3,397 240 2,060 MAIS 1: Minor 386,398 2,647 7,004 621 5,987 MAIS 2: Moderate 45,443 562 13,137 1,069 2,842 MAIS 3: Serious 1,840 72 8,497 718 1,308 MAIS 4:Severe 370 18 3,025 302 538 MAIS 5/6: Critical/Maximum 80 2 490 46 68 Injured, Severity Unknown 52 0 9 3 8 Total 518,211 4,236 35,558 2,997 12,809

Source: CODES data from CT, KY (admitted only), MD, NE, NY, SC, UT, with KY and SC data from 2006-07 weighted by 1.5 to represent 2006-08. Counts in Table 2 by MAIS severity do not sum to counts by police-reported severity because Maryland did not code MAIS for 2,628 cases.


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Table 3. Cases Analyzed, Estimated Percentage Alcohol-Involved (BAC+), and Percentage of Alcohol-Involved Drivers Who Police Reported as Alcohol-Involved by Injury Severity, by Place of Treatment, Pooled Data for 7 States

CT/MD/NE/NY/SC/UT * Add KY *

All Standard

Error ED Only Standard

Error Admitted Standard

Error Admitted Standard

Error Cases 580,878 538,581 42,297 48,607 %BAC+ 6.8% 0.07% 5.4% 0.06% 22.5% 0.41% 22.6% 0.35%

% of BAC+ Who Police Reported as BAC+ O 27.4% 3.29% 30.5% 3.60% 19.6% 7.66% 20.2% 7.39% C 43.6% 1.90% 46.5% 2.08% 35.5% 4.39% 39.2% 3.82% B 49.1% 1.59% 53.7% 1.79% 40.2% 3.28% 44.7% 2.77% A 50.5% 1.86% 59.4% 2.70% 46.1% 2.48% 49.6% 2.12% All ABC 47.6% 1.00% 51.5% 1.10% 41.8% 1.81% 45.8% 1.55% All ABCO 43.8% ** 1.02% 46.9% 0.82% 38.7% 1.56% 42.6% 1.35%

MAIS 0 42.9% 2.54% 45.5% 2.64% 29.9% 8.12% 31.4% 7.64% MAIS 1 45.4% 1.42% 47.1% 1.50% 37.1% 4.12% 38.9% 3.86% MAIS 2 42.6% 2.17% 47.0% 3.25% 40.0% 2.89% 43.1% 2.56% MAIS 3 39.7% 3.40% 40.4% 10.69% 39.6% 3.57% 44.6% 2.92% MAIS 4 40.6% 5.18% 36.4% 21.31% 40.8% 5.29% 48.0% 3.99% MAIS 5/6 30.1% 16.92% *** *** 31.1% 16.82% 35.3% 14.86%

* With SC and KY case counts weighted by 1.5. ** Weighted with the police-reported national injury severity distribution for alcohol-involved drivers, the percentage of alcohol use that police report for all alcohol-involved drivers in nonfatal crashes would be 34.2%. *** Too few cases to support estimation. Table 4. Estimated Percentage of Hospital-Treated Alcohol-Involved Drivers Who Medical Records Indicated Were Alcohol-Involved by Injury Severity and Place of Treatment, Pooled Data for 7 States

CT/MD/NE/NY/SC/UT pooled * Add KY *

All ED Only Admitted Admitted O 17.1% 14.6% 51.0% 49.1% C 32.9% 30.1% 51.4% 52.6% B 37.5% 32.7% 60.9% 59.4% A 42.1% 36.5% 46.7% 46.9% All ABC 33.6% 32.0% 51.7% 51.3% All ABCO 32.5% 27.5% 51.3% 51.2%

MAIS 0 39.5% 38.3% 52.2% 49.7% MAIS 1 27.3% 25.3% 55.5% 54.5% MAIS 2 36.4% 24.8% 54.2% 53.4% MAIS 3 46.1% 31.0% 48.6% 49.3% MAIS 4 44.8% 34.5% 45.4% 48.6% MAIS 5/6 24.7% ** 26.3% 28.5%

* With SC and KY case counts weighted by 1.5. ** No cases.


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Table 5. Cases Analyzed, Estimated Percentage Alcohol-Involved (BAC+), and Percentage of Alcohol-Involved Drivers Who Police Reported as Alcohol-Involved by State and Injury Severity

CT MD NE NY SC UT KY* Cases 55,694 84,146 9,257 312,149 59,881 29,806 4,209 %BAC+ 7.2% 4.7% 9.0% 6.4% 7.3% 7.1% 23.1%

% of BAC+ Who Police Reported as BAC+ O 23.7% 45.8% 66.7% 23.8% 10.2% 68.3% 40.0% C 24.4% 58.0% 72.6% 47.8% 25.5% 83.4% 68.4% B 26.7% 63.2% 76.4% 65.4% 24.8% 85.6% 71.4% A 27.5% 65.4% 74.3% 57.3% 29.1% 79.7% 68.0% All ABCO 25.9% 60.5% 74.8% 44.7% 25.1% 81.6% 68.2%

MAIS 0 28.3% 62.9% 86.7% 47.1% 23.6% 77.1% 53.3% MAIS 1 26.0% 64.5% 75.6% 45.4% 24.7% 86.2% 70.3% MAIS 2 25.5% 55.8% 73.8% 43.0% 25.2% 80.2% 68.0% MAIS 3 22.1% 53.9% 67.6% 40.5% 26.5% 74.6% 67.2% MAIS 4 15.5% 61.3% 80.0% 40.5% 28.3% 64.0% 70.6% MAIS 5/6 ** 33.3% ** 33.3% 18.8% 55.6% 66.7%

* Kentucky only had data on admitted cases. ** No cases.

Table 6. Estimated Percentage of Hospital-Treated Alcohol-Involved Drivers Who Medical Records Indicated Were Alcohol-Involved by State and Injury Severity

CT MD NE NY SC UT KY* O 36.3% 17.3% 22.9% 14.5% 25.5% 28.0% 31.6% C 53.7% 37.3% 33.8% 28.2% 33.3% 40.2% 58.1% B 55.0% 46.2% 35.2% 26.5% 36.3% 41.6% 54.7% A 59.9% 58.9% 39.9% 34.2% 46.4% 37.7% 47.4% All ABCO 52.5% 40.5% 35.8% 24.9% 37.4% 38.5% 50.6%

MAIS 0 64.6% 38.8% 38.2% 33.9% 35.1% 50.0% 34.8% MAIS 1 45.8% 30.4% 34.5% 21.0% 30.9% 37.3% 46.4% MAIS 2 53.1% 55.4% 35.3% 24.6% 44.2% 35.5% 49.5% MAIS 3 64.2% 62.7% 44.2% 35.4% 51.2% 38.5% 51.3% MAIS 4 52.9% 65.4% 40.0% 36.6% 50.0% 28.1% 55.4% MAIS 5/6 ** 40.0% ** 21.2% 30.0% 26.3% 36.4%

* Kentucky only had data on admitted cases. ** No cases. Table 7. Comparison of Drivers per Driver Reported as Seriously Injured (A) and Percentage of Drivers Reported as Alcohol-Involved by Police-Reported Injury Severity, National Data from General Estimates System, 2010, Versus Linked Data on Hospital-Treated Cases from CODES, 2006-2008

Driver Injury Severity Cases per A Driver, GES

Cases per A Driver, CODES

Alcohol-involved, GES

Alcohol-Involved, CODES

O-No Injury Observed 63.1 5.2 1.9% 2.1% C-Posible Injury 7.5 7.1 2.4% 1.8% B-Evident Injury 3.5 2.6 8.5% 5.6% A-Serious Injury 1 1 11.8% 9.3% All ABC 12.0 10.7 5.0% 3.6% All ABCO 75.2 15.9 2.4% 2.3%


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Table 8. Nationwide Alcohol Involvement (BAC+) in Nonfatal Crashes Reported in 2010 General Estimates System, Ratio of Crashes by Police-Reported Crash Injury Severity per Alcohol-Involved Driver by Police-Reported Driver Injury Severity, and Estimated Alcohol Involvement Adjusted for Underreporting.

Police-Reported Alcohol-Involved Adjusted for

Underreporting

Severity BAC+

Drivers BAC+

Crashes BAC+

Drivers BAC+

Crashes %

Reported %BAC+ Drivers

%BAC+ Crashes

O 151,760 121,859 1.9% 3.6% 27.4% 6.9% 13.1% C 22,941 37,940 2.4% 3.6% 43.6% 5.6% 8.4% B 37,908 48,264 8.5% 8.2% 49.1% 17.3% 16.7% A 14,902 20,730 11.8% 11.4% 50.5% 23.4% 22.6% All ABC 75,751 106,934 5.0% 5.9% 47.7% 10.5% 12.5% All ABCO 227,511 228,793 2.4% 4.4% 34.2% 7.5% 12.9%

Figure 1. Percentage of Drivers Alcohol-Involved by Police-Reported Crash Severity, United States, 2010

13.1%8.4%

16.7%22.6%

38.3%

3.6% 3.6%8.2% 11.4%

25.9%

No Injury PossibleInjury

EvidentInjury

SeriousInjury

Fatal

All Alcohol-InvolvedPolice-Reported Alcohol


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Documents

Underreporting of driver alcohol involvement in United States police and hospital records: Capture-recapture estimates