Technical Report

Evaluation of Checkpoint Tennessee:

Tennessee's Statewide
Sobriety Checkpoint Program

John H. Lacey
Ralph K. Jones
Randall G. Smith

January 1999

Prepared for:
U.S. Department of Transportation
National Highway Traffic Safety Administration
Washington, DC 20590

Contract Number DTNH22-94-C-05064


Mid-America Research Institute, Inc. of New England
Winchester, Massachusetts

Technical Report Documentation Page

1. Report No. 2. Government Accession No. 3. Recipient's Catalog No.
4. Title and Subtitle

Checkpoint Tennessee: Tennessee's Statewide Sobriety Checkpoint Program

5. Report Date

January 1999

6. Performing Organization Code

7. Author(s)

Lacey, J. H.; Jones, R. K.; and Smith, R .G.

8. Performing Organization Report No.

9. Performing Organization Name and Address

Mid-America Research Institute
611 Main Street
Winchester, MA 01890

10. Work Unit No. (TRAIS)

11. Contract or Grant No.

DTNH22-94-C-05064

12. Sponsoring Agency Name and Address

National Highway Traffic Safety Administration
Office of Research and Traffic Records
400 7th Street, S.W.
Washington, DC 20590

13. Type of Report and Period Covered

Final Report

14. Sponsoring Agency Code
15. Supplementary Notes

James Fell was the Contracting Officer's Technical Representative (COTR) for this project

Appendices are only available on the printed version of this report. Request it from the Sponsoring Agency (see above).

16. Abstract

Tennessee implemented an extensive statewide sobriety checkpoint program (Checkpoint Tennessee). Checkpoints were scheduled on each weekend of the year in at least four counties in the state. On five weekends checkpoints were scheduled in each of the state's 95 counties. The volume of checkpoints increased from about 15 in the preceding year to nearly 900 in the program year. Grant funds were used to support training and equipment but checkpoints were staffed using existing personnel resources. Extensive checkpoint activity was continued after the formal program completion. The checkpoint activity was publicized extensively both through public service advertising and earned media. Interrupted time series analyses were used to evaluate the program. The program resulted in a 20.4% reduction in alcohol related crashes extending at least 21 months after conclusion of the formal program. This resulted in a savings of nine fatal alcohol-related crashes per month in Tennessee.

17. Key Words

impaired driving, sobriety checkpoint, roadblocks, passive alcohol sensors, DUI, DWI, drunk driving, alcohol-related crashes, Checkpoint Tennessee, enforcement and public information

18. Distribution Statement

This report is available from the National Technical Information Service, Springfield, Virginia 22161
(703) 487-4650

19. Security Classif. (of this report) 20. Security Classif. (of this page) 21. No. of Pages 22. Price

Form DOT F 1700.7 (8-72) Reproduction of completed page authorized

ACKNOWLEDGMENTS

The authors are grateful to the many individuals who worked on this project. We would especially like to thank the following individuals for participating in the implementation of the project in Tennessee:


TABLE OF CONTENTS

ACKNOWLEDGMENTS

EXECUTIVE SUMMARY

1 - INTRODUCTION

BACKGROUND

PROJECT SCOPE AND APPROACH

ORGANIZATION OF THE REPORT

2 - PROGRAM DESCRIPTION

CHECKPOINT PROGRAM

PUBLIC INFORMATION ACTIVITIES

3 - PROGRAM EVALUATION

ENFORCEMENT ACTIVITY

PUBLIC AWARENESS

EFFECT ON CRASHES

4 - SUMMARY AND CONCLUSIONS

REFERENCES

FIGURES

Figure 2-1: Checkpoint Tennessee Logo

Figure 3-1: ARIMA Model of Drunk-Driving Fatal Crashes in Tennessee, All Fatal Crashes as an Input (1988-1996)

Figure 3-2: ARIMA Model of Drunk-Driving Fatal Crashes in Five Comparison States, All Fatal Crashes as an Input (1988-1996)

Figure 3-3: Nighttime Single-Vehicle Injury Crashes in Tennessee, 1989-1996

TABLES

Table 3-1: Attributes of Driver Survey Respondents, Percentage by Wave

Table 3-2: Response to Questions about Exposure to Highway Safety Programs

Table 3-3: Responses to Selected Questions on Opinions and Behavior


EXECUTIVE SUMMARY

Sobriety checkpoints have long been known to be an effective impaired driving enforcement method. In a review of the literature, it was concluded that the accumulation of positive findings for visible and well-publicized checkpoints provide support for the proposition that sobriety checkpoints are capable of reducing the extent of alcohol-impaired driving and of deaths and injuries on the highway (Ross, 1992a). However, until recently, checkpoints have generally only been implemented in the United States (U.S.) on a local level.

While these results have been encouraging, for various reasons (Ross 1992b) very few states in the U.S. have embarked on statewide sobriety checkpoint programs. Based upon their potential effectiveness, and the strong evidence from Australia on their random breath testing (RBT) program (Homel, 1990), the National Highway Traffic Safety Administration (NHTSA) decided to conduct a demonstration project in a state that was willing to change its philosophy and approach about checkpoints.

In 1993, NHTSA entered into a cooperative agreement with the State of Tennessee to conduct a highly publicized sobriety checkpoint program throughout the state and evaluate the effects of that program. In March 1994, Tennessee initiated a statewide impaired driving checkpoint program labeled "Checkpoint Tennessee." The NHTSA grant funded equipment purchases, some logistics, and the evaluation. The personnel required to staff the checkpoints were provided though diversion of existing resources in the Tennessee Highway Patrol. Four sets of three checkpoints were conducted throughout the state every weekend using specially equipped vans with generators, lights, cones, signs, video taping and evidential breath testing equipment. Officers also used passive alcohol sensors in flashlights to detect the odor of alcoholic beverages, and used standardized field sobriety tests to detect impaired drivers. On five weekends during the project year checkpoints were scheduled each of the 95 counties in the state. By necessity these did not involve as many officers or as much equipment per checkpoint as was typical during other weekends but they served to reenforce the "blitz" concept.

The checkpoints were coordinated and conducted primarily by the Tennessee Highway Patrol with support from local law enforcement agencies. Publicity in support of the program was stimulated by obtaining the special cooperation of a single television station in each of the five major markets in the state. They each broadcast Checkpoint Tennessee as a special project. This publicity was enhanced by "hard news" coverage from other outlets, a statewide billboard campaign, and press releases announcing individual checkpoints, followed up by reports of their results in terms of arrests, etc. Television, radio and print media coverage was extensive during the 12 month operations phase of the program.

Three waves of a paper and pencil survey were administered in several driver's license renewal offices to measure knowledge and attitudes about the program. The first wave was administered in March 1994 prior to the formal announcement and initiation of the Checkpoint Tennessee program. The second wave was administered in the summer of 1994, four months after program initiation and the third wave was administered in the spring of 1995, at the conclusion of the formal phase of the project. The first wave yielded 1,305 respondents while the second wave yielded 1,071 and the third, 1192 respondents. The results of several questions indicated increased awareness of the Checkpoint Tennessee program, as well as overwhelming support for the program.

Between April 1, 1994 and March 31, 1995, a total of 882 checkpoints were held. This compares to the typical 10-15 checkpoints conducted on an annual basis for the 5 years prior to the demonstration project, yielding quite a contrast in programs. A total of 144,299 drivers passed through these checkpoints with 773 arrested for driving under the influence of alcohol (DUI) or driving while intoxicated (DWI). An additional 201 drivers were arrested for drug violations, 84 for youth offender violations, 35 felony arrests were made, 49 weapons were seized, 1,517 were cited for safety belt or child restraint violations and 7,351 were given other traffic citations.

An interrupted time series approach was used in analyzing the traffic-safety impact of the checkpoint program. The independent variable and measure of effectiveness in the model was "drunk driving fatal crashes." A drunk driving fatal crash was defined as a fatal crash in which one of the involved drivers had a blood alcohol concentration (BAC) of 0.10% or more either through direct BAC test results or through an algorithm developed by NHTSA (Klein, 1986). The data covered the period 1988 through 1996.

Two techniques were used to guard against attributing any changes in drunk driving fatal crashes to the program when they might have been due to some other events that just happened to coincide with the program. First, a model of drunk driving fatal crashes in five states surrounding Tennessee (Kentucky, Georgia, Alabama, Mississippi, and Louisiana) was developed using the same procedures to see if an effect occurred coincident with Tennessee intervention. Such an effect might be indicative of a regional or, possibly, a national factor having nothing to do with the intervention. All fatal crashes were also included as an explanatory variable in the model for Tennessee and the model for the five surrounding states.

The model showed a significant effect for the intervention variable in Tennessee(a step function coincident with the checkpoint program start date) amounting to a reduction of about nine drunk-driving fatal crashes per month (t ratio=7.06). This was a 20.4% reduction over the projected number of drunk-driving fatal crashes that would have occurred with no intervention.

The model for the comparison series used 12-span differencing of the dependent variable "drunk-driving fatal crashes," and used the same differencing of the independent variable "all fatal crashes". Again, the transfer function was equal to 1. The model showed an insignificant increase in drunk-driving fatal crashes in the five surrounding states coincident with the Tennessee intervention, lending support to the hypothesis that the checkpoint program was responsible for the positive results observed in Tennessee.

A parallel analysis using nighttime single-vehicle injury crashes as a proxy of alcohol-related crashes revealed a statistically significant reduction of 5.5% after the start of the Checkpoint Tennessee program.

While other statewide sobriety checkpoint programs have recently been initiated in the U.S. (in North Carolina and New Mexico, to name two) this demonstration in Tennessee is of interest because it resulted in a significant decrease in alcohol-related traffic fatalities with relatively low implementation costs. The total cost of the two-year demonstration project was $927,594, with federal funding at $452,255 and state matching funding at $475,339. The state contribution covered police salaries, publicity costs and other program expenses. The police salary contribution was accomplished by a reallocation of effort to this endeavor rather than through additional funding. NHTSA funding covered some public information and education materials, equipment and program evaluation. The Tennessee approach to Checkpoint scheduling might be characterized as a "sustained checkpoint blitz" effort with several checkpoints each weekend as opposed to a quarterly or bimonthly blitz as implemented in North Carolina and New Mexico, respectively.

The State of Tennessee has elected to continue with the checkpoints, although not at the same frequency or intensity as the 12-month operational phase described in this report. That is also considered a successful outcome since federal funding stimulated the initiation of a program that the state deems to be effective and has decided to continue.

Many of the reasons for the non-use of sobriety checkpoints (e.g., they are too expensive, require too much personnel, do not yield enough DWI arrests) (Ross, 1992b) are being overcome by the results of this program and of those in North Carolina and New Mexico (Lacey, Jones and Fell, 1995). A recent study (Stuster and Blowers, 1995) shows that sobriety checkpoints yield greater public awareness of the program and greater decreases in alcohol-related crashes than an enforcement program involving roving patrols. The premise of highly visible, highly publicized, frequent sobriety checkpoints conducted on a statewide basis appears to be a viable, effective deterrent to impaired driving. Other states should consider implementing statewide programs. For those states where they are not permitted measures to remove those legal barriers should be undertaken or similar alternatives pursued.

1 - INTRODUCTION

This report describes the steps taken in the implementation and evaluation of a statewide sobriety checkpoint program undertaken by the State of Tennessee to demonstrate the feasibility and effectiveness of implementing a sustained, year-long, statewide checkpoint blitz to deter impaired driving. The project was undertaken under the sponsorship of the U.S. Department of Transportation National Highway Traffic Safety Administration (NHTSA) through NHTSA Cooperative Agreement Number DTNH22-93-Y-05264.

BACKGROUND

Sobriety checkpoints have long been known to be an effective impaired driving enforcement method. In a review of the literature, it was concluded that the accumulation of positive findings for visible and well-publicized checkpoints provide support for the proposition that sobriety checkpoints are capable of reducing the extent of alcohol-impaired driving and of deaths and injuries on the highways (Ross, 1992a). However, until recently, checkpoints have generally been implemented in the United States (U.S.) on a local level. A well-publicized sobriety checkpoint program held in Binghamton, New York, resulted in a 39 percent decrease in the number of drinking drivers on the roads at night according to roadside surveys and a 23 percent reduction in late-night crashes in the months the checkpoints were held (Wells, Preusser and Williams, 1991). In New Jersey, checkpoints were associated with a drop of 10 to 15 percent in single vehicle nighttime crashes (a commonly used measure of alcohol-impaired driving) (Levy, Shea and Asch, 1988). A year-long checkpoint program in Charlottesville, Virginia was associated with a 13 percent reduction in the proportion of crashes that were alcohol-related (Voas, Rhodenizer and Lynn, 1985). Similar results were obtained from a checkpoint program in Clearwater and Largo, Florida, which experienced a 20 percent decrease following checkpoint operations (Lacey, Stewart, Marchetti, Popkin, Murphy, Lucke and Jones, 1986).

While these results have been encouraging, for various reasons (Ross, 1992b) very few states in the U.S. have embarked on statewide sobriety checkpoint programs. Based upon their potential effectiveness, and the strong evidence from Australia on their random breath testing (RBT) program (Homel, 1990), the National Highway Traffic Safety Administration (NHTSA) decided to conduct a demonstration project in a state that was willing to change its philosophy about checkpoints.

PROJECT SCOPE AND APPROACH

The overall intent of the demonstration project was to test whether it was feasible to implement a sustained, statewide DWI sobriety checkpoint enforcement program for a twelve-month period and to assess the effect of such a program on alcohol-related crashes. Tennessee felt strongly that this project should attempt to demonstrate to other states the feasibility of implementing a program such as this in a way that those jurisdictions could reasonably expect to adopt themselves. Thus, a conscious decision was made not to use any of the NHTSA funding to pay for officer enforcement time. All of the funds for enforcement activities were from existing resources of participating local and state agencies. Federal funds were expended for equipment, training costs, reproduction of informational materials, the purchase of billboard posting materials and evaluation of the program. Again, Federal funds were not expended for personnel costs associated with program implementation or enforcement.

Another salient aspect of the program was that Tennessee chose to implement a sustained statewide checkpoint program which involved conducting checkpoints across the state during every weekend of the year (weather permitting) rather than periodic blitzes every few months . The sustained program was supplemented on occasion by well publicized efforts to conduct at least one checkpoint in each of the State's 95 counties. This occurred on the initial kickoff weekend and during selected holiday periods. Since this was a statewide effort, the Department of Safety, Tennessee Highway Patrol (THP) took the lead in coordinating and implementing enforcement activities. The THP was represented at every one of the checkpoints described in this report but was usually assisted by local and county officers in the conduct of the checkpoints.

The program was initially intended to be conducted and evaluated on the basis of a one year implementation period (April 1, 1994 through March 31, 1995). However, because of the special nature of the Tennessee program -- using existing personnel resources for the actual conduct of the enforcement -- it was thought that the program might continue in some form after the formal conclusion of the project. Thus, it was decided to extend the crash evaluation follow up period until the end of 1996 to assess the longer term impact of this type of approach on crashes.

The evaluation examines the level of enforcement activity stimulated by the project, public receptiveness and awareness of the increased enforcement efforts and the impact of the overall effort on alcohol-related crashes.

ORGANIZATION OF THE REPORT

Chapter 2 describes the process used in implementing the Checkpoint Tennessee program and its supporting public information activities. Chapter 3 discusses the evaluation process and its results, Chapter 4 contains the summary and conclusions of this report.

2 - PROGRAM DESCRIPTION

CHECKPOINT PROGRAM

This program was a joint effort of the Tennessee Department of Transportation, Governor's Highway Safety Office (GHSO) and the Tennessee Department of Safety, Tennessee Highway Patrol (THP). The GHSO initiated the program through the development and planning stages while the Tennessee Highway Patrol took the lead in the implementation of checkpoint activities. Central planning for the enforcement activities was coordinated by the Planning and Research Section of the THP. A statewide plan and schedule for the implementation of the checkpoints for the full year was developed and distributed through the chain of command to a lieutenant in each of the Patrol's eight districts who was responsible for the implementation of the schedule. (A portion of the schedule appears in Appendix A as an example.) The basic schedule was constructed so that each of the eight districts was assigned two nights each month on which three checkpoints were to be conducted. This insured that at least 576 checkpoints would be conducted during the twelve month operational period if the schedule were adhered to strictly. Of course, there were occasions when inclement weather precluded strict adherence to the schedule.

These core checkpoints were conducted following the guidelines contained in the Tennessee Department of Safety General Order pertaining to Sobriety Checkpoints (Appendix B). The general order requires that at least six troopers and a supervisor staff the checkpoint and that other specific measures be taken to insure that the checkpoints meet all the requirements of statutory and case law for sobriety checkpoints.

During this project these core checkpoints included the use of special equipment purchased with project funds. Special equipment included specially outfitted vans which were equipped with an intoxilyzer, a video recorder with two cameras (one to tape field sobriety tests administered outside the van and one to tape breath alcohol tests administered inside the van), special lighting and auxiliary equipment. Auxiliary equipment included twenty passive alcohol sensors, cones, reflective vests, generator and floodlights. Much of this equipment was transported in trailers towed by each of the vans.

Four sets of equipment were purchased for this project. Specific troopers were assigned responsibility for maintaining and operating the equipment. The vans were stationed in four districts spread across the state so that they would be readily available to where the checkpoints were conducted. Specialized training was held for the van operators and their assistants in the operation of the vans and associated equipment. They in turn were able to provide training to officers staffing each checkpoint. This included both local and county law enforcement officers as well as THP personnel. To assist in some of this training a new General Order was promulgated to cover the use of passive alcohol sensors. A copy of that general order and a descriptive brochure about the Passive Alcohol Sensors used in this project appear in Appendix C. A State Attorney General's ruling required that the passive sensors be held outside the driver's window during checkpoint interviews in order to be non-intrusive. The ideal use of the passive sensor in checkpoint operations is to place it inside the vehicle so that a more direct reading of the driver's breath may be obtained. Even though the passive sensors were not used in the optimal manner during this project it was reported by police that drivers at lower breath alcohol levels were being identified and that passive sensors enhanced checkpoint operations.

In addition to ensuring appropriate Highway Patrol participation, the district lieutenants coordinated activities with local police agencies in the areas where the checkpoints occurred, informed the local district attorneys of the activity, and also were responsible for informing local media of the checkpoints and of their results so as to maximize local hard news coverage of the checkpoint activity.

Besides the core checkpoints described above, five times during the project year, the Tennessee Highway Patrol chose to conduct weekend blitzes in which checkpoints were scheduled in each of the 95 counties in Tennessee. Clearly, with only four sets of special equipment it was not feasible to conduct 95 full-scale checkpoints on these weekends. Thus the scheduled, full-scale, core checkpoints were supplemented by what is termed Enforcement Roadblocks in the other counties. A copy of the General Order covering Enforcement Roadblocks appears in Appendix D. These roadblocks do not have the same personnel and equipment requirements as sobriety checkpoints and thus it was feasible to allocate the personnel to conduct them statewide on five occasions during the project year. These occurred at the initiation of the operational phase of the project (April, 1 1994), during the Memorial Day period, the July 4th Holiday, the Labor Day Holiday, and at the conclusion of the project year.

After each weekend each district submitted reports to the Planning and Research Section documenting Checkpoint Tennessee activity which was summarized and used for both management and public information purposes. Additionally, local summaries were distributed to appropriate local media by each district.

PUBLIC INFORMATION ACTIVITIES

It was felt that mass media -- television, radio, newspapers, and outdoor advertising -- is a very powerful influence in our society and that using them for publicity could play an important role in the potential success of the Checkpoint Tennessee program. Though the checkpoints themselves would offer contact with a large number of drivers they would still only reach a small fraction of the potential drinking drivers in Tennessee. It was assumed that effective use of the media would greatly enlarge the number of persons reached by the Checkpoint Tennessee message. An objective was to demonstrate that a law enforcement agency could mount an effective public information campaign, designed to enhance the effectiveness of a sobriety checkpoint program, using already existing internal resources. Therefore, federal funding was not requested to supplement the public information officer's time nor were the services of a public relations or advertising firm engaged.

The primary concern of the public information program was to attempt to sustain media interest in the sobriety checkpoint program throughout at least the first year's implementation. To accomplish this, Checkpoint Tennessee had to remain newsworthy throughout the operational period, not just in the initial stages.

In developing the media plan, Tennessee decided to use public service announcements (both television and radio) as the primary avenue to reach the public. The print media and outdoor advertising would play secondary roles in the public service advertising (PSA) area. Public service advertising was to be supplemented by hard news coverage whenever feasible and by brochures and other handouts. Early on, a distinctive logo was developed and incorporated into virtually all publicity material (Figure 2-1). The following is a discussion of each media type and the activities associated with them.

Television

In order to ensure the use of the public service announcements, a decision was made to select one television station in each of Tennessee's five market areas to be a "flagship" station (Memphis WREG, Nashville WTVF, Chattanooga WTVC, Knoxville WBIR and Tri-Cities WJHL). The rationale behind this decision was that the project had to be assured that any PSAs developed would be broadcast, and broadcast at times when they would be viewed. The project director went to the station managers and program directors of the selected stations and offered them a deal. If they would agree to broadcast the Checkpoint Tennessee PSAs during some prime time hours for a one- year period, they would have first access to information about the program. They would be allowed on-site at sobriety checkpoints in their area, be given data about sobriety checkpoint activity in their area (number of arrests, etc.) before their counterparts, and quarterly updates on activities statewide. None of the stations refused the offer. A potential concern was that other television stations might refuse to cover the checkpoint program because they were not a flagship station. However, this did not come to pass. Whenever sobriety checkpoints were conducted, virtually all media in the area covered them.

One of the flagship stations, WTVF in Nashville, assisted in the development of the PSAs and made them available to the other flagship stations at no charge. The PSAs were 10, 15 and 30 seconds in length. These PSAs were broadcast a total of 720 minutes during the one year activity period.

The Checkpoint Tennessee program received continuous TV hard news coverage throughout the year. All of the flagship stations produced special series about Checkpoint Tennessee and the problem of alcohol impaired drivers. In addition, a series about other impaired driving issues began to surface in news broadcasts. For example, WSMV in Nashville produced a ten part series entitled "Unlicensed to Kill." This series aired each night for two weeks and focused on the problem of drivers with their license revoked for impaired driving still operating a motor vehicle. The amount of earned media generated by Checkpoint Tennessee was at least 156 minutes in addition to the PSAs.

Print

The intent was to use the print media to accomplish two basic tasks: to help to "spread the word" about Checkpoint Tennessee; and to inform the public about checkpoint activities in their community.

Before the start of the program the project manager visited the editorial board of the major newspapers in each of the five areas of the state described above. The purpose of the visit was to inform them of the impaired driving problem in Tennessee and to receive an editorial endorsement of the program. All five newspapers published editorials supportive of the Checkpoint Tennessee program.

When sobriety checkpoints were held in a community, the supervising officer was instructed to inform the media about the upcoming checkpoints. This was done to obtain the maximum deterrent value from the checkpoints. Data about the checkpoints were collected and arranged in a table format, and on the Tuesday following the weekend checkpoints they were mailed, hand-carried or faxed to the local newspapers. The thought was that immediate feedback to the community was imperative to the success of the program. More general media releases such as quarterly updates were sent to all media outlets across the state throughout the program. Checkpoint Tennessee received at least 11.715 column inches of print coverage. An example of a press release appears in Appendix E and examples of news articles in Appendix F.

Radio

Radio offers an opportunity to reach motorists while they are driving their vehicle. They could even be engaging in the risky behavior that the intervention is targeting. Radio stations were provided with PSAs which were the sound tracks from the television PSAs. Troopers visited the radio stations, explained the program and left the PSAs and printed materials. Troopers were interviewed about the program by local radio stations during the Checkpoint Tennessee effort. The interviews were usually conducted at times when checkpoints were being held within the community. Radio PSAs were played a total of 1,100 minutes.

Outdoor Advertising

Tennessee has used outdoor advertising in highway safety programs for many years. They feel that billboards (like radio) are an effective way to reach motorists while they are actually driving their vehicle. That is, they provide a good "point of sale message."

3M National Media was contacted about the possibility of donating billboard space for Checkpoint Tennessee. They agreed to design the artwork and provide space in four major urban areas of the state (Memphis, Nashville, Chattanooga, and Knoxville) and in nine rural locations if the project could obtain funding to purchase the actual materials to be posted.

Funding for outdoor advertising was not in the basic demonstration grant. However, the American Coalition for Traffic Safety (ACTS) was willing to consider funding outdoor advertising. The project director approached ACTS about Checkpoint Tennessee's needs along these lines. ACTS agreed to provided $20,000 for these materials if a buckle-up seat belt message was incorporated into the billboards.

The project director selected 20 locations in the urban areas along the most heavily traveled interstate corridors in the state. They offered exposure to over one million vehicles daily. Forty percent of Tennessee's population lives in those four urban cities and 59% of the state's population lives within the Standard Metropolitan Statistical Areas of those cities.

The nine billboards placed along rural interstates had an exposure of approximately 250,000 vehicles per day.

The message was printed on a vinyl material which allowed the messages to be moved to various locations in the cities. Using this material permitted paying for printing only once. The average stay in any given location was three weeks. Moving the message from board to board provided even broader coverage. It is estimated that had the billboard space been purchased, it would have cost $800,000.

Printed Items

A brochure describing the program and summarizing the impaired driving laws was developed and printed. Over 150,000 copies were printed and distributed to the public by the THP. Additionally, thousands of promotional items such as pins, cups, pencils, etc. were printed and distributed at checkpoints and other law enforcement events.

3 - PROGRAM EVALUATION

ENFORCEMENT ACTIVITY

During the period preceding introduction of the Checkpoint Tennessee program the Tennessee Highway Patrol averaged 10 to 15 sobriety checkpoints per year. In the cooperative agreement application, the THP proposed conducting 576 checkpoints during the implementation year. Obviously, this was a tremendously increased number of checkpoints, particularly when one considers that they were to be staffed using existing patrol resources. There was no special funding for officer overtime. Essentially the mechanism was a change of command emphasis. Officers were to be diverted from other duties to conduct the checkpoints. Additionally, cooperation and support was obtained from the Tennessee Association of Chiefs of Police and the Tennessee Sheriffs' Association. Tennessee Highway Patrol district supervisors were instructed to contact local law enforcement agencies when planning checkpoints and encourage their participation. This was intended to both ease the personnel burden of the THP and to foster an overall spirit of cooperation.

The main mechanism for evaluation of the extent to which checkpoints were actually conducted was a special reporting mechanism put into place by the THP. Every Monday each of the eight THP districts was required to submit reports of activity at each checkpoint conducted the previous weekend (Appendix A). These reports were tabulated by personnel in the THP Planning and Research Section into a statewide summary report (Appendix A) and used both to monitor implementation of the program and to provide input for regular news releases to the statewide media.

The latter report is the final statewide activity report from the formal project implementation year. One can see that 882 checkpoints were conducted under the auspices of the program, well above the 576 in the original commitment. Nearly 145,000 vehicles passed through the checkpoints and over 9,000 were detained for further investigation. There were 773 resultant DUI arrests, 347 seat belt citations and 465 child restraint citations. Additionally, 705 written seat belt warnings were issued as well as 7,351 other traffic citations.

In addition to traditional traffic safety violations, numerous other violations of the law were detected and appropriate action taken. Four stolen vehicles were recovered, 35 felony arrests were made for violations such as drugs, bootlegging and parole violations. In addition 201 arrests for misdemeanor drug violations were made.

Thus, the program clearly exceeded the contractual requirement in terms of number of checkpoints conducted, and yielded many additional enforcement actions.

While other statewide sobriety checkpoint programs have recently been initiated in the U.S. (in North Carolina and New Mexico, to name two) one reason this demonstration in Tennessee is of special interest because of the relatively low implementation costs. The total cost of the two-year demonstration project was $927,594, with federal funding at $452,255 and state funding at $475,339. The state contribution covered police salaries, publicity costs and other program expenses. The police salary contribution was accomplished by a reallocation of effort to this endeavor rather than through additional funding. NHTSA funding covered some public information and education materials, equipment and program evaluation.

PUBLIC AWARENESS

Public awareness was measured in a number of ways. The Department of Safety administered brief paper and pencil surveys at driver's license offices across the state, the Department of Health added two questions about checkpoints to the Behavioral Risk Factor Surveillance System survey they conduct, mail back cards were distributed at some checkpoints and informal data about perceptions of checkpoint activity were gathered from nighttime bar and club patrons.

Driver's License Office Surveys

Three waves of a paper and pencil survey were administered in driver's license offices in support of the Checkpoint Tennessee evaluation activities. The first wave of the survey was administered in March 1994 prior to the formal announcement and initiation of the Checkpoint Tennessee program, a second wave was administered during the summer of 1994 beginning four months after program initiation and the third wave was administered in the spring of 1995 at the conclusion of the formal program. Wave 1 yielded 1,305 respondents, Wave 2 resulted in 1,071 respondents and Wave 3 surveyed 1,192 respondents. The survey form appears as Appendix G.

In terms of demographics (gender, age, race) respondents in each wave were similar as well as in terms of their reason for being at the driver's license office (Table 3-1).

Two open-ended questions were asked about exposure to highway safety programs: one was about drinking and driving and one was about seat belt use. As indicated in Table 3-2, relatively few individuals responded to these open-ended questions. The salient response change with respect to drinking-driving is that only two persons (1%) mentioned roadblocks in Wave 1 while 24 (18%) did in Wave 2. The most frequent responses to the open-ended questions about seatbelt use were the Vince and Larry commercials and the "Buckle up, it's the law" message. Mentions of the former message decreased after Wave 1, but mentions of the latter message increased after Wave 1.

Attribute Wave p
1 2 3
Number of Responses 1305 1071 1192  
 

Reason at License Office

      0.001

First License

13.2 15.6 14.9  

Renew License

26.8 31.2 32.7  

Reinstate License

16.3 12.0 14.8  

Get ID

10.9 5.8 4.9  

Other

32.9 35.3 32.6  
 

Sex

      0.259

Male

49.4 50.8 52.7  

Female

50.6 29.2 47.3  
 

Age

      0.001

<18

10.0 12.1 11.4  

18-20

8.9 9.7 6.4  

21-24

15.3 16.4 12.7  

25-29

14.3 12.3 14.7  

30-49

43.8 41.0 41.7  

50-65

6.1 6.6 10.7  

Over 65

1.7 2.1 2.4  
 

Race

      0.112

Caucasian

66.0 68.3 71.6  

African American

24.8 22.7 20.8  

Other

9.2 9.0 7.7  

 

Wave

1

2

3

Drinking-Driving

Total Responses

205

134

330

Roadblocks Mentioned

2

24

6

% Roadblocks Mentioned

1.0

17.9

1.8

 

Seatbelts

Total Responses

125

98

271

Vince & Larry Commercials Mentioned

65

31

67

% Vince & Larry Mentioned

52.0

31.6

24.7

"Buckle up, it's the law" Mentioned

16

25

16

% "Buckle up..." Mentioned

30.8

79.0

64.7

One question was intended to measure perceived risk of arrest and was phrased as follows, "Suppose you drive after drinking enough to violate Tennessee's drinking and driving law. What are you chances of being arrested by the police?" At Wave 1, 47% of respondents thought that the risk of arrest was 60% or greater, and this figure did not change much in succeeding waves (Table 3-3).

Opinion / Behavior Wave
1 2 3

Chances of Arrest if DWI

47.0% 43.5% 47.0%

Drive < 2 hours after drinking

17.4% 15.6% 14.1%

Drinking-Driving > once in past 3 months

8.6% 7.3% 6.0%

Been through a checkpoint

7.9% 10.5% 8.7%

Support Checkpoints

88.1% 91.6% 91.4%

Use a Seatbelt

59.7% 65.7% 63.0%

Respondents were also asked, "How often do you drink alcoholic beverages and then drive within a couple of hours?" The percentage of persons admitting to this behavior in Wave 1 was 17.4% but dropped off slightly in Waves 2 and 3 (Table 3-3). They were then asked about impaired driving with the question, "Within the last 3 months, how often do you think you may have driven after drinking too much?" At Wave 1, 8.6% of respondents admitted to engaging in this behavior at least once, and this percentage decreased slightly in Waves 2 and 3. There was virtually no change in the pattern of responses to the question asking whether their drinking driving behavior had changed compared with three months ago.

There was also virtually no change in the percentage of respondents reporting having been stopped by a police officer at night, 7.9% saying "yes" at Wave 1 (Table 3-3). At all waves the public overwhelmingly supported the use of checkpoints -- 88.1% at Wave 1, 91.6% at Wave 2, and 91.4% at Wave 3. Finally, self-reported seat belt usage increased several percentage points during the Checkpoint Tennessee program. At Wave 1, 59.7% said they always wore their belt, 65.7% claimed so at Wave 2, and 63% at Wave 3.

In summary, through this measure, though there was only slight change in public awareness of enforcement activity, measures of perceived risk of arrest and self-reported drinking driving behavior showed improvement. There was substantial improvement in self-reported seat belt use. However the most striking finding is how overwhelmingly the public supports the use of DUI roadblocks to combat drinking and driving, with nine out of ten drivers indicating support.

Behavioral Risk Factor Surveillance System Survey

The Behavioral Risk Factor Surveillance System Survey is a monthly random digit dialing statewide telephone survey with a range of 200 to 250 respondents monthly. It is intended to measure changes in behavior relative to risks to the population's health. The Tennessee Department of Health agreed to place two supplemental questions about checkpoints on the survey for a seven month period from March through September 1994. This afforded us one measure before the public announcement of the program and six measures during the first half-year of the implementation period.

The first question was "During the last 30 days, has a vehicle you were driving or one in which you were a passenger been through a DUI roadblock?" On the March 1994 survey 5.1% of respondents reported having been through a roadblock. In subsequent months the figures were as follows: April, 4.8%; May, 4.9%; June, 6.2%; July, 9.9%; August, 8.6%; and September, 6.2%. Thus there is a slight trend towards increased exposure to checkpoints, particularly in the summer months. However, the baseline measure is quite high given that few checkpoints were conducted during the period preceding that administration of the questionnaire.

The other question was "Do you support the use of DUI roadblocks to combat drinking and driving?" In March 1994, 88.8% of respondents reported they supported roadblocks. Support remained consistently high with 91.1% in April, 93.1% in May, 92.2% in June, 95.8% in July, 94.1% in August, and 91.7% in September 1994 supporting roadblocks. Even though the baseline support for sobriety checkpoints was very high, after the initiation of checkpoints and the associated publicity, support increased.

Survey of Drivers Passing through Checkpoints

The Tennessee Highway Patrol distributed prepaid postcards to persons passing through checkpoints. Of those mailing back written responses, 155 offered positive comments and 26 negative. Examples of the comments are:

Negative

Positive

Informal Assessment of Awareness in Clubs and Bars

On one checkpoint weekend, research project personnel conducted an informal survey of patrons in drinking establishments in the general area where checkpoints were conducted.

Ten establishments were visited and informal discussions held with 21 individuals.

Virtually all of those with whom the project personnel spoke were aware that there had been a recent police crackdown on drinking and driving. Two-thirds of the 21 persons were able to articulate specifically that DUI Checkpoints were being conducted.

Anecdotal Observations from Checkpoints and Surrounding Areas

Project team members observed several checkpoints throughout the project. Two general observations were that in many vehicles containing both a male and female (often pick-up trucks), the woman was driving and a man who had obviously been drinking was the passenger and it was observed that at some popular bars cars were being parked overnight.

Police reported that these patterns were different than the typical experience before the initiation of Checkpoint Tennessee, leading one to believe that the program may have been encouraging the use of designated drivers and alternative transportation.

EFFECT ON CRASHES

An interrupted time series approach was used in analyzing the traffic safety impact of the checkpoint program. In this approach, a time series of the data of interest is studied to see if an "intervention" occurring at some point in the series is a statistically significant factor in a mathematical model of the series. The intervention analyzed here is the Checkpoint Tennessee program.

The dependent variable and measure of effectiveness in the model was "drunk driving fatal crashes." A drunk driving fatal crash was defined as a fatal crash in which one of the involved drivers had a blood alcohol concentration (BAC) of 0.10% or more either through direct BAC test results or through an algorithm developed by NHTSA (Klein, 1986). Ideally, all classifications would be through direct BAC tests, however no state as yet obtains a BAC test of all drivers in fatal crashes and this approach is considered to be the best available alternative. The data used in the model were retrieved from NHTSA's Fatal Accident Reporting System (FARS). (The FARS has subsequently been renamed the Fatality Analysis Reporting System. The data covered the period 1988 through 1995.)

Two techniques were used to guard against attributing any changes in drunk driving fatal crashes to the program when they might have been due to some other events that just happened to coincide with the program. First, a model of drunk driving fatal crashes in five states surrounding Tennessee (Kentucky, Georgia, Alabama, Mississippi, and Louisiana) was developed using the same procedures to see if an effect occurred coincident with Tennessee intervention. Such an effect might be indicative of a regional or, possibly, a national factor having nothing to do with the intervention. All fatal crashes were also included as an explanatory variable in the model for Tennessee and the model for the five surrounding states.

Nominally, the statistical analysis assumed a program start date of April 1, 1994, but we also studied the effect of assuming several other start dates to account for a possible lag between the time the program was started and the time an impact occurred. It was assumed that a step-function intervention was appropriate for the majority of the analyses, and the effect of interventions of other time profiles, for example, a ramp function, was studied.

The ARIMA analysis method developed by Box and Jenkins in the 1970s, and incorporated in the SAS statistical package as PROC ARIMA, was used.

The best fit to the Tennessee series was obtained through a model using all drunk-driving fatal crashes as the dependent variable. All fatal crashes were used as an input series. The transfer function for the input series was a simple scalar of value equal to 1. The model showed a significant effect for the intervention variable (a step function coincident with the checkpoint program start date) amounting to a reduction of about nine drunk-driving fatal crashes per month (t ratio=-7.06). This was a 20.4% reduction over the projected number of drunk-driving fatal crashes that would have occurred with no intervention.

The results are depicted graphically in Figure 3-1. The heavy line (labeled "model, program") represents the ARIMA time-series model fitted to the actual data. The light line (labeled "model, no program") shows what the series would have been after the start of the checkpoint program had there been no program.

The model for the comparison series used 12-span differencing of the dependent variable (drunk-driving fatal crashes), and used the same differencing of the independent variable (all fatal crashes). Again, the transfer function was equal to 1. The model showed a very small, insignificant increase in drunk-driving fatal crashes in the other states coincident with the Tennessee intervention (t ratio=0.21, Figure 3-2), lending support to the hypothesis that the checkpoint program was responsible for the positive results observed in Tennessee. (Note that the increase is too small to show as a separate curve in the figure.)

In another analysis of crashes of lesser severity, nighttime single-vehicle injury crashes were used as a measure of alcohol-related crashes. An ARIMA model of these crashes was developed using all nighttime crashes as an explanatory variable. The model also included an intervention variable written as a step function with a value of zero prior to the intervention (April 1, 1994), and a value of one thereafter. The analysis showed a small but statistically significant (t=-2.20) reduction of about 5.5% in the alcohol-crash surrogate after the start of the intervention (Figure 3-3).

Thus, analyses of both alcohol-related fatal crashes and nighttime single vehicle injury crashes consistently indicate a statistically significant effect associated with the implementation of the Checkpoint Tennessee program.

4 - SUMMARY AND CONCLUSIONS

The overall intent of this project was to test if it was feasible to implement a sustained year long statewide sobriety checkpoint program and, if implemented, if such a program resulted in a reduction in alcohol-related crashes and fatalities.

In developing the cooperative agreement, it was agreed that conducting 576 checkpoints in Tennessee over a twelve month period would constitute such a program. They were to be conducted in all areas of the state, with several checkpoints being held each weekend. In fact, during the Checkpoint Tennessee program, 882 checkpoints were held and, during five blitz periods, checkpoints were scheduled in each of the State's 95 counties. Thus, this project demonstrated that a sustained year long statewide checkpoint program could be implemented.

A key feature of Tennessee's approach was that they did not use funds from the cooperative agreement to pay salaries for enforcement personnel staffing the checkpoints. Rather they reassigned personnel from other duties to the checkpoints. This demonstrates that even such an extensive program can be implemented with existing resources.

The second major intent of the project was to see if implementation of such a program would result in a decrease in alcohol-related crashes and the attendant deaths and injuries. Interrupted time series analyses from the Fatality Analysis Reporting System revealed a 20.4% reduction in alcohol related crashes. This represents a savings of about nine fatal crashes per month. There was also a significant 5.5% decrease in nighttime single-vehicle injury crashes. These are dramatic reductions and they were sustained for at least twenty-one months after completion of the formal program.

Survey data indicate overwhelming support for the conduct of checkpoints. Consistently nine out of ten respondents to both the paper and pencil and the telephone surveys indicated that they supported the use of sobriety checkpoints to combat impaired driving. Even persons passing through checkpoints supported their use. Eighty-five percent of those sending in mail- back comment cards offered positive comments.

Often in the case of research projects such as this, even when there are positive results, once the formal project is over activity ends and the beneficial effect disappears. One intent of the project team in proposing not using Federal funds to pay for staffing the checkpoints was to demonstrate that this type of program is feasible to implement in the real operating world of law enforcement. During the first year after the end of the formal program, the Tennessee Highway Patrol conducted 245 sobriety checkpoints. This compares favorably to the ten to fifteen which were conducted annually in the years leading up to the Checkpoint Tennessee program. Traffic Enforcement Roadblocks have also been continued. In fact, 1,327 were held in the twelve month period subsequent to the completion of the formal Checkpoint Tennessee program and are being continued at an even higher rate.

Thus, though the volume of formal sobriety checkpoints is somewhat less than during the project year, it is still much higher than before, and traffic enforcement roadblock activity continues at an even higher rate. This may well account for the continued over 20% reduction in fatal crashes. Continued monitoring of FARS data to determine if these reductions are maintained is recommended.

In summary, an intensive, sustained, highly publicized and visible statewide sobriety checkpoint program can be implemented. Such a program can have dramatic effects on alcohol related crashes and their untoward consequences and can be extremely cost-beneficial. The program can be continued with existing resources and the beneficial effect maintained.

With such dramatic effects resulting in numerous lives saved, it is incumbent on policy makers and administrators to find ways to implement similar programs in their states.

REFERENCES

Homel, R. Random breath testing and random stopping programs in Australia. In Wilson, RJ and Mann, R. (Eds), Drinking and Driving: Advances in Research and Prevention. New York: Guilford Press, pp 159-204, 1990.

Klein, T. A method for estimating posterior BAC distributions for persons involved in fatal traffic crashes, National Highway Traffic Safety Administration, Washington, DC, DOT HS-807-094, 1986.

Lacey, J., Stewart, J., Marchetti, L., Popkin, C., Murphy, P., Lucke, R. and Jones, R. Enforcement and Public Information Strategies of DWI General Deterrence: Arrest Drunk Driving: The Clearwater and Largo, Florida Experiences. Technical Report. Washington, DC: National Highway Traffic Safety Administration, DOT HS-807-066, 1986.

Lacey, J., Jones, R. and Fell, J. A comparison of blitz versus continuous statewide checkpoints as a deterrent to impaired driving, In Proceedings of the 13th International Conference on Alcohol, Drugs and Traffic Safety, Volume 2, Kloeden and McLean (Eds), pp 845-848, 1995.

Levy, D., Shea, D., and Asch, P. Traffic safety effects of sobriety checkpoints and other local DWI programs in New Jersey. American Journal of Public Health, 79: 291-293, 1988.

Miller, T.R., Galbraith, M.S., and Lawrence, B.A. Costs and benefits of a community sobriety checkpoint program. Journal of Studies on Alcohol, 59, 4:462-468, 1998.

Ross, H.L. The deterrent capability of sobriety checkpoints: Summary of the American Literature. Technical Report. Washington, DC, National Highway Traffic Safety Administration, DOT HS-807-862, 1992a.

Ross, H.L. Reasons for non-use of sobriety checkpoints. Police Chief, Vol. LIX, No. 11, pp 58-63, 1992b.

Stuster, J. and Blowers, P. Experimental Evaluation of Sobriety Checkpoint Programs, Technical Report., Washington, DC, National Highway Traffic Safety Administration, DOT HS-808-287, 1995.

Voas, R., Rhodenizer, E., and Lynn, C. Evaluation of Charlottesville Checkpoint Operations: Final Report. Technical Report., Washington, DC, National Highway Traffic Safety Administration, DOT HS-806-989, 1985.

Wells, J., Preusser, D., and Williams, A. Enforcing alcohol-impaired driving and seat belt use laws, Binghamton, NY. Insurance Institute for Highway Safety, Arlington, VA, 1991.


APPENDIX A

Sample Checkpoint Schedule

APPENDIX B

General Order for
Sobriety Checkpoints

APPENDIX C

General Order for
Passive Alcohol Sensors
and
Description of Passive Sensors

APPENDIX D

General Order for
Traffic Enforcement Roadblocks

APPENDIX E

Sample Press Release

APPENDIX F

Examples of Newspaper Coverage

APPENDIX G

Driver's License Survey
Tennessee Department of Safety Survey on Highway Safety Issues

The Tennessee Department of Safety needs your help in providing information about highway safety issues. Your answers will be used for statistical purposes only. Please do not write your name on this form.

1. Why are you at the driver's license office? (CIRCLE ONE)
a. To get first licensed. To get an I.D. only
b. To renew currently valid licensee. Other
c. To have license reinstated
2. Your sex? (CIRCLE ONE)
a. Maleb. Female
3. Your age? (CIRCLE ONE)
 a. Under 18c. 21-24e. 30-49g. Over 65
b. 18-20d. 25-29f. 50-65
4. Your race? (CIRCLE ONE)
a. African-Americanc. Hispanice. Caucasian
b. American Indiand. Asianf. Other

5. What new Tennessee programs dealing with drinking and driving have you seen, heard about, or read about in the last three months (on TV, radio, in the newspapers, posters, etc.)? Please write in.

The program Where seen, heard or read

_________________________________________ _________________________

_________________________________________ _________________________

_________________________________________ _________________________

6. What new Tennessee programs dealing with encouraging seat belt use have you seen, heard about, or read about in the last three months (on TV, radio, in the newspapers, posters, etc.)? Please write in.

The program Where seen, heard or read

_________________________________________ _________________________

_________________________________________ _________________________

_________________________________________ _________________________

7. Suppose you drive after drinking enough to violate Tennessee's drinking and driving law. What are your chances of being arrested by the police? (CIRCLE ONE)

a. 0%c. 20-39%e. 60-79%
b. 1-19%d. 40-59%f. 80-100%

8. How often do you drink beer, wine or liquor? (CIRCLE ONE)

a. Every dayc. Once a weeke. Less than once a month
b. Several times a weekd. Once a monthf. Never

9. How often do you drink alcoholic beverages and the drive within a couple of hours? (CIRCLE ONE)

a. Every dayc. Once a weeke. Less than once a month
b. Several times a weekd. Once a monthf. Never

10. Within the last three months, how often do you think you may have driven after drinking too much? (CIRCLE ONE)

a. Every dayc. Once a weeke. Less than once a month
b. Several times a weekd. Once a monthf. Never

11. A. Compared with three months ago, are you driving after drinking: (CIRCLE ONE)

a. More often?b. Less often?c. About the same?
d. Do not drive after drinking

B. If it changed, please say why:

_______________________________________________________________________

12. How many times in the past 3 months has a vehicle you were driving been stopped by a police officer at night?_______

13. How often do you wear seat belts? (CIRCLE ONE)

a. Alwaysb. Most of the timec. Sometimesd. Never

A. Compared with three months ago, are you wearing seat belts: (CIRCLE ONE)

a. More often?b. Less often?c. About the same?

B. If it changed, please say why:

_______________________________________________________________________

15. In the past 3 months has a vehicle you were either driving or been a passenger in been through a DUI roadblock?

(CIRCLE ONE)a. Yesb. No

16. Do you support the use of DUI roadblocks to combat drinking driving?

(CIRCLE ONE)a. Yesb. No