Acrid. Anal. and Preu. Vol. 25. No. 5. pp. 511-520, 1993 Printed in the U.S.A.

0001-4575193 $6.00 + .OO 0 1993 Pergamon Press Ltd.

NONSANCTION SEAT BELT LAW ENFORCEMENT: A MODERN DAY TALE OF TWO CITIES*

WILLIAM W. HUNTER, J. RICHARD STEWART, JANE C. STUTTS, and LAUREN M. MARCHETTI

Highway Safety Research Center, University of North Carolina, Chapel Hill, NC, U.S.A.

(Receiued 22 July 1991; in revised form 12 Augtrsf 1992)

Abstract-This paper describes the implementation and evaluation of a nonsanction seat belt law enforcement program in two experimental communities of contrasting size in a state with a mandatory belt law. The main ingredients of the program were seat belt “salutes,” public information and education, and limited use of inexpensive economic incentives. Driver shoulder belt use data collected before, during, and after the experimental programs, compared to similar data collected in a comparison community, showed the approach to be effective. While standard seat belt enforcement activities without incentives have been shown to be effective, many police departments, especially in smaller communities, are reluctant to make wholesale increases in seat belt citations. Although requiring some additional level of manpower and resources, a nonsanction approach to seat belt law enforcement can provide an alternate way of increasing belt use in these communities.

INTRODUCTION

North Carolina’s seat belt law became effective on October 1, 1985. The law provides for primary en- forcement (i.e. a person can be stopped and ticketed solely for not wearing a seat belt). Violators (drivers and front seat occupants) were issued warning tick- ets during a IS-month grace period. As of January 1, 1987 violators have been subject to a $25 fine. Enforcement of the law by the North Carolina State Highway Patrol has been excellent, whereas en- forcement at the local level has been variable (Rein- furt et al. 1990).

Statewide observational surveys of drivers and front seat passengers in North Carolina have been conducted both prior to the law and at intervals throughout the warning and citation phases. The results of these surveys showed a remarkably con- sistent 45% driver usage rate throughout the warning phase, in contrast to a baseline rate of 25% obtained just before the law became effective. At the onset of the citation phase, the driver use rate increased dramatically to 78%. One year later (January 1988) the rate had decreased to slightly above 60%. Since that time, the driver use rate has remained close to 60%.

Seat belts can reduce the risk offatal and serious

* Presented at the 35th Annual Meeting of the Association for the Advancement of Automotive Medicine, October 7-9, 1991, Toronto Canada.

injuries in motor vehicle crashes by 40% or more (Campbell 1987; Hedlund 1985; Evans 1986). How- ever, considerably higher belt compliance will be needed to approach these reductions in individual states, and safety advocates continue to seek ways to increase belt use rates. The literature shows that enforcement blitzes involving public information, warning tickets, and actual citations have produced dramatic belt use increases in Canada (Jonah and Grant 1985; Dussault 1990) and in Elmira, New York (Williams et al. 1987). The comprehensive Quebec campaign described in Dussault is one of the most effective efforts to date, resulting in a belt use rate of around 85%.

However, there is good reason to proceed with the evaluation of a nonsanction type of program. Local police agencies in North Carolina devote vary- ing levels of enforcement attention to the state’s adult seat belt and child restraint laws (Reinfurt et al. 1990). Officers feel more comfortable in issuing citations to violators of the state’s child passenger protection law because they feel parents should take the responsibility for safeguarding children who can- not protect themselves. However, discussions have revealed that some officers are not inclined to en- force the seat belt law because of: (i) a perception of little cooperation from the courts, (ii) the feeling that detection and enforcement are difficult, (iii) their personal belief that adults should have the right to choose to wear (or not wear) belts, (iv) their own

511

512 W. W. HUNTER et al.

skepticism about the effectiveness of belts, and (v) a view that there are more important laws to enforce.

Police enforcement efforts are also held back by community attitudes. Particularly in smaller towns where the officers are well acquainted with many townspeople, there may be greater reluctance to en-

force belt laws more than others such as drunk driv- ing or speeding. Also, many North Carolina police officers have indicated that enforcement of the law is strictly dependent on the priority that their police chief places on enforcement, regardless of how they personally feel about the law.

This paper describes a national demonstration project funded by the National Highway Traffic Safety Administration. Police departments in two different-sized communities in the western Pied- mont region of North Carolina planned and imple- mented belt promotions during a one-year grant pe- riod (October 1, 1989-September 30, 1990). The actual media activities, seat belt checkpoints, and other main promotions lasted about seven months. The emphasis of the project was on nonsanction or “soft” police enforcement reminder strategies, namely: (i) the widespread use of seat belt “sa- lutes,” where an officer tugs on his/her shoulder belt in a “thumbs up” manner as a reminder to an unprotected motorist to buckle up, (ii) a modified incentive program whereby properly restrained local motor vehicle drivers could win prizes when spotted by police (e.g. through seat belt or license check- points or through the recording of license plate infor- mation), and (iii) comprehensive public information and education (PI&E). The University of North Car- olina Highway Safety Research Center (HSRC) se- lected the communities, served in an advisory role during the planning and implementing of the promo- tions, and evaluated the performance.

DESCRIPTION OF PROGRAM

Site selection It was felt that the demonstration program had

the best chance of success in a relatively small com- munity with population ranging from 15,000-30,000, where “getting the word out” would not be a formi- dable task. However, resources were also available to try the concept in a second community, and it was thought that a considerably larger location would provide an interesting comparison. Thus, two com- munities in the western Piedmont area of North Car- olina were chosen as experimental sites: Albemarle, a small textile-oriented community with a population of 16,000, and Gastonia, also textile-oriented but with a population of 60,000. Both had preliminary belt use rates of around 50%, or about 10 percentage

points below the statewide average. A third site, Statesville, with a midrange population of 2S,OOO and a similar belt use rate, was chosen as a compari- son site. Both experimental sites had active pro- grams for about seven months (mid-November I989 through mid-June 1990), although a few of the Albe- marle activities lasted a bit longer.

The main purpose of the public information and education (PI&E) and other programs conducted by both the Albemarle and Gastonia police departments was to sensitize the motoring public to the need for safety belts through positive, upbeat messages presented by law enforcement officers. Although seat belt use is mandated by law, the thrust of the efforts was to make the public feel that they should buckle up for safety reasons and that it was out of this concern for safety that the police departments were conducting these programs.

HSRC’s approach was to work with each of the departments in developing an overall PI&E plan (see Figs. 1 and 2) for the project period and providing technical assistance in the development of materials. The local agencies were responsible for the actual materials production and distribution. Initial plan- ning meetings were held in which the general pro- gram elements (e.g. theme, logo, prizes, and distri- bution) were defined. Training of local police about the importance of belts and role modeling was done in separate meetings.

The Gastonia Police Department chose the theme, “Protect the Best-Gastonia Buckles Up,” to project the message that Gastonia motorists are “the best” and that wearing seat belts is part of being the best. Albemarle chose the theme, “Albemarle Clicks-Buckle Up and Survive the Drive.” The slogan and logo were used on all promotional materi- als developed for each community. High visibility applications of the logo included banners (four in Albemarle, two in Gastonia), which were hung at heavily traveled crosstown arteries; brochures (5,000 in Albemarle, 10,000 in Gastonia) and bumper stickers (2,000 in Albemarle, 5,000 in Gastonia) that were given out to motorists; and silk-screened T-shirts (1,000 in Albemarle, 1,200 in Gastonia), key rings, (2,000 in Albemarle, 10,000 in Gastonia), and other items that were given to belted motorists as prizes through numerous seat belt checkpoints and at drive-up windows. Several thousand other small prizes (rulers, caps, frisbees) were given out at school presentations. Other PI&E activities in- cluded were seat belt salutes, seat belt checkpoints, appearances by the television crash dummies Vince and Larry, special “Lifeguard” programs at the lo-

Nonsanction seat belt law enforcement

ALBEMARLE PUBLIC INFORMATION AND EDUCATION PROGRAM

November 1989 _ September 1990

PROGRAM KICKOFF

Seat Eel! Salutes Sea! Belt Checkpoinh Vince and Larry Costumes Child Sea! Rental Program Lifeguard Program Automatic Sea! Belt Prograr Pickup Truck Program

Presentations

Radio News Radio PSA’s

Print News

TV News

Banners Signs

Parade

Nov Dee Jan Feb Mar Apr May Jun Jul Aug Sep : : : : ; : : f ; : : ; i j ; i z

*i ; ; i I ; i ; i f <

i : 3 j ; t i i

i : i : : j i ; i i

513

Fig. I. Albemarie public information and education program,

cal high schools, fliers to encourage correct restraint use in vehicles equipped with automatic belts and airbags, fliers to encourage belt use by pickup truck drivers, and active media support. Mass media activ- ities at both sites included numerous articles in local newspapers and lesser numbers of television and radio public service announcements and news spots.

EVALUATION METHODOLOGY

The general project methodology was a before/ after design with comparison site. There were two experimental sites (Albemarle and Gastonia) utiliz- ing the nonsanction program and one comparison site (Statesville) with no special program. A primary purpose for including the comparison site was to permit the identification of trends in seat belt use resulting from statewide or regional promotional ac- tivities. Such trends could then be separated from any program effects at the experimental sites.

Shoulder belt use data were collected through- out the project and served as the main dependent

variable. Some 8-10 intersections were chosen as data collection points in each community. The inter- sections were selected to represent the various socioeconomic elements present. Data were con- sistently collected by randomly assigning the intersections to four time-of-day periods: morning peak, morning off-peak, afternoon off-peak, and af- ternoon peak. The observers were visible to drivers and likely served as campaign reminders once the drivers understood the reason for their presence. Although the analysis was not able to assess the independent contribution of visible seat belt observ- ers to the campaign success, their presence may have been an important component of the overall program, especially in the smaller community of Al- bemarle.

At each data collection site, driver shoulder belt use data were obtained for all passenger motor vehi- cles equipped with shoulder belts. Each round of data collection produced about 2,000 observations in Albemarle and 5,000 observations in Gastonia. The data were coded separately for passenger cars

514

PROGRAM KICKOFF

Seat Belt Salutes Seat Belt Checkpoints Vince and Larry Costumes Child Seat Rental Program Lif~uard Program Automatic Seat Belt Prograr Prckup Truck Program

Presentations

Radio News Radio PSA’s

Print News

TV News

Utility Bill Fliers

Bank Promotion

Drawing for Prizes

School Contests

Parade

W. W. HUNTER et al.

GASTONtA PUBLIC INFORMATION AND EDUCATION PROGRAM

November 1989 - September 1990

No\ -

0

b

-

Jan Feb Mar Apr May Jun : j / : : : : : : / : i : : : i j : : : ; j / ; : ! ; : : : i i i i j : : : : : : : : i ; b j 5

Fiy. 2. Gastonia public information and education program.

and minivans (hereafter referred to as ‘“passenger vehicles”) and for pickup trucks, vans, utility vehi- cles, and other vehicles (referred to as “pickups”). In addition to belt use, race and sex of the driver were also collected because these variables have been linked with differences in belt use in prior studies.

Data were analyzed both descriptively and more formally using categorical regression models. For the latter, data were aggregated within each project period to represent overall or average seat belt use rates for: fi) the baseline period prior to the officiat initiation of any seat belt programs, (ii) the program period during which the various promotions were carried out, and (iii) the period after the special programs had been completed. For purposes of com- parison, the data for Statesville were also partitioned into these same three time periods, even though no program was in effect. Categorical data models were then fit to the resulting seat belt use rates using SAS PROC CATMOD (SAS Institute, Cary, NC).

RESULTS

Ovemll belt USC cl~ungys by community. Both experimental communities experienced an increase in the driver shoulder belt use rate (hereafter re- ferred to as belt use rate) during and after the non- sanction program. Initial data were collected in March 1989, followed by other “before” data points in May and October of 1989. Kickoffs for both pro- grams occurred in November (November IS or Week 35 for Albemarle and November 20 or Week 38 for Gastonia). Figure 3 show-s the overall trends in belt use rates for all three communities throughout the study. The plot shows a substantial rise in the belt use in Albemarle and a lesser increase in Gasto- nia. The comparison community of Statesville had a higher belt use rate to begin with and stayed rela- tively flat during the data collection except for an increase at the end (see discussion below).

More detail for each community can be seen in

Nonsanction seat belt law enforcement 515

40 60 80 Week

Fig. 3. community belt use rates.

Fig. 4. During the before period, the Albemarle belt use for all vehicles showed an increase from 48% to 56% (Fig. 4a). The Albemarle community use rate remained around 54%-56% after the kickoff and then gradually rose to a peak value of 68% in Week 61 (May 1990). This was followed by a slight de- crease and then a rise back to 64% for the last data point in Week 76 (September 1990). The changes in the plots for both the passenger vehicles and the pickups were quite similar over time. Only in the after period was there much of a divergence, where the pickup belt use was continuing to decrease.

The Gastonia belt use varied from 47% to 49% in the before period (Fig. 4b). During and after the program in Gastonia, the overall belt use rate fluc- tuated between 46% and 53%. The last data point, collected in Week 86 (October 1990), was the peak value. As with the Albemarle data, the passenger vehicle and pickup belt use generally tended to vary in concert.

Figures 4a and 4b show growth in belt use to occur slowly in both Albemarle and Gastonia (12- 14 weeks after official program start) as if the campaign needed a minimum time before showing an effect. This was followed by a gradual increase in belt use. This is not uncommon in community programs, as increasing proportions of the population are reached (Campbell et al. 1984).

The Statesville comparison site data collection was started in June 1989, and the initial overall belt use rate was 53% (Fig. 4~). The community belt use hovered in this vicinity for about one year and then rose to around 57% near the end of data collection (mid-August to late October 1990-Week 65 to

Week 74). This rise in belt use was almost surely

associated with an unexpected change in seat belt enforcement policy in the community. Through March of 1990, the Statesville police wrote an aver- age of only about six seat belt citations per month. Over the next seven months, the number of citations increased dramatically, peaking at 69 in May 1990. During this intensive enforcement period, the police were operating almost exclusively in community areas of lower socioeconomic status where drug use was known to be a problem. Since North Carolina has a primary seat belt enforcement law, police were using the failure of front seat occupants to wear belts as a means of stopping vehicles and then observing for drugs. Besides word-of-mouth in the community, the seat belt citations, along with other citations, were documented in the local newspaper. Since the highest belt use rates coincided with this active en- forcement phase, it seems apparent that there was a strong association.

In contrast, the experimental communities of Albemarle and Gastonia followed our request to stay at about the normal seat belt citation level during the program, since the emphasis was on “soft” en- forcement. Both communities averaged about 4-5 citations per month during the campaign and the ensuing four months.

It may be noted that the last observation prior to the official start of the Albemarle program is higher than the initial baseline observations, and, in fact, is very much in line with the early program period observations. One possible explanation is that in the small community of Albemarle, enough preprogram activity had taken place that, in effect, the program had already started by the time these last preperiod observations were made. A second

516 W. W. HUNTER et al

a) Albemarle

4i Week

b) Gastonia

I I . I

40 60 80 100 Week

c) Statesville

I 20 40

Week

I I 60 80

Fig. 4. Belt use by vehicle type.

possible explanation is that an increasing trend in seat belt use in Albemarle was already underway independent of any program activity. If this were the case, and this trend continued through the program period, it would account for virtually all of the in- crease in seat belt use seen during the program pe-

riod. Two arguments against this second explanation are:

1. No reason is known why such a trend should be occurring in Albemarle; it certainly is not seen in the comparison site of Statesville.

Nonsanction seat belt law enforcement 517

nor in the North Carolina statewide use rates noted earlier, and

2. If there was such a trend that continued through the program period, would it not be expected to continue beyond the end of the program? If so, then all of the seat belt obser- vations in the after period lie far below their expected values.

The first explanation certainly seems the more plau- sible.

Belt use by sex of driver. The growth in the belt use rate in Albemarle was a function of increases for both male and female drivers (Fig. 5a). The varia- tion in belt use over time was virtually identical for the two groups, but with the female use rate consistently higher than the male use rate, as is gen- erally the case. The peak use rate for female drivers was 76% and for mafe drivers 58%-both in Week 61 (May 1990). The same tendency was true in Gastonia (Fig. Sb), but with Lower peak values. In Statesville, the comparison community, there was a bit more fluctuation in the male driver use rate, otherwise the same kind of trends.

Belt use by race of driver. The changes in driver belt use by race tended to mirror the changes in belt use by driver sex in Albemarle (Fig. 6a). The fluctuations were larger for the nonwhite group, most likely related to smaller numbers of observa- tions. The peak belt use rate for both groups (68%) occurred just prior to the end of the formal program (Week 61). The belt use rates for white and nonwhite drivers also tended to move in concert in Gastonia (Fig. 6b). The plots by race in Statesville (Fig. 6c) were both relatively flat, with some increase toward the end of data collection.

Belt use by race and sex of driver. Examining belt use changes by driver race and sex simulta- neously showed a consistent pattern for all three communities with the groups tending to cluster by sex of driver. White female drivers consistently showed the highest use rate, but the nonwhite fe- males were relatively close behind, followed in turn by white males and then nonwhite males.

SigniJicance testing In accordance with the basic experimental de-

sign, analyses were carried out to determine (i) whether or not, during the program period, seat belt use rates increased significantly over their baseline values in the experimental cities and (ii) whether or not the observed increases in the experimental cities were significantly greater than those in the compari- son city. The analyses were carried out by fitting categorical data models to the overall seat belt use

rates for the three cities aggregated over each of the three time periods (baseline, program, and follow- up). These data are shown in Table 1. These models were formulated to test the two hypotheses specified above, and not to characterize week-to-week changes in use rates during the program period, etc. The basic model contained parameters representing the baseline use rates in the three cities and six parameters representing the period-to-period changes.

Table 2 shows estimated model parameters and their standard errors from this model. All of the period-to-period changes are statistically significant (i.e. the estimated value exceeds two standard er- rors). Most notable is the baseline to program period increase in Albemarle of 8.5 percentage points com- pared to the 1.6 percentage point decrease in States- ville. The relatively large increase from the program period to the after period of 4.6 percentage points in Statesville is likely due to the noted large increase in seat belt enforcement_

A similar model comparing seat belt use in pas- senger cars with belt use in pick-up trucks in the three communities showed belt use changes in both vehicle types to essentially parallel the overall changes shown in Table 2, but with the use rates for passenger car drivers consistently about 17 per- centage points higher than the use rates for pickup truck drivers. Thus, for example, in Albemarle the baseline rates were about 39% for pickup trucks and 59% for passenger cars, while in the after period the rates were 49% and 65%, respectively.

A third model examining use rates by commu- nity, time period, and driver race and sex showed that the increase in belt use in Albemarle from base- line to the program period was very consistent for all race/sex groups. Overall, these statistical models were able to detect significant positive results for the nonsanction programs, especially in Albemarle but also to a lesser extent in Gastonia.

DISCUSSION

From a practical standpoint, the results of the nonsanction seat belt enforcement program show a clear increase in belt use in one site and a marginal increase in the second site when compared to a third site where no program was initiated. The gains in belt use seen in both experimental communities were “across the board” with respect to driver sex, race, and vehicle type.

The community of Albemarle (population 16,000) increased their belt use over 10 percentage points when the overall before and after belt use rates were compared. Gastonia’s (population

518 W. W. HUNTER et al.

a) Albemarle

80

40

Week

b) Gastonia

80

0 40 60 80 100

Week

c) Statesville

*O 1

‘

40 40 80

Week

Fig. 5. Belt use by sex of driver.

60,000) overall belt use increased approximately brevity of the after period, the duration of the belt three percentage points during the comparable pe- use increases is not known, although Albemarle’s riod. During the height of the programs, the Albe- use rate remained at 64% three to four months after marle belt use peaked at 68%, in excess of the North the height of the program. Carolina statewide average of about 60%, while the The different outcomes for the two experimen- Gastonia peak belt use reached 53%. Due to the tal program sites are not extremely surprising. A

Nonsanction seat belt law enforcement 519

a) Albemarle

0 20 40 Week

60 80

b) Gastonia

80

70

3 60 S

d i 50

a” 40

30 I e I . t I

I_ I

0 20 40 60 80 100

Week

c) Statesville 80

m 4i io ii0 Week

Fig. 6. Belt use by race of driver.

Table 1. Seat belt use rates by city and time period

City Baseline Program After

AlbemarIe ,515 ,600 .622 Gastonia .485 ,498 so9 Statesville ,538 .521 .567

relatively small population coupled with strong me- dia coverage from local newspapers and radio sta- tions were key factors in the success of the Albe- marle program. Added to this was a high level of commitment to the project by the police chief, which translated into active participation by aIt members of the force. In contrast, the task of “getting the

520 W. W. HUNTER et al

Table 2. Estimated model parameters for overall belt use model (standard errors in parenthesis below parameter estimate\)

Baseline Baseline to Program to City rate program change follow-up change

Albemarle ,515 ,087 ,015” c.006) (.007) ( ,004)

Gastonia ,485 .Ol2 .015” (.004) (.005) (.004)

Statesville .538 - ,016 ,045 t.006) l.007) (.008)

* Because the separate parameters that represented the change from program to follow-up in both Albemarle and Gasto- nia did not differ significantly. a single parameter could be used.

word out” was much more difficult in Gastonia, with its larger population and more diffuse media market. Officer participation was also less active when com- pared to that in Albemarle.

HSRC has been involved in evaluating pro- grams designed to increase belt use for almost a decade, and in many respects this current project reinforces some outcomes seen in earlier projects. First, belt use programs tied to the use of PI&E and some amount of economic incentives regularly succeed if there is dedicated effort by program orga- nizers and other staff and volunteers. Even with strong dedication and considerable project activity, however, belt use increases typically take some time to emerge, as if some amount of critical mass results from continued exposure to the program.

Secondly, the probability of success for projects like these is directly associated with size of commu- nity. “Getting the word out” is vital and is simply more effectively accomplished in smaller communi- ties of around 30,000 population or less. Much more mass media impact is necessary in a larger environ- ment, and the chance for success is improved if the community lies in a self-contained media market where competition for exposure is low.

Thirdly. the use of economic incentives is an important ingredient. Although use of incentives played a minor role in this “soft enforcement” proj- ect, it is unlikely that the concept would have been as successful using merely “seat belt salutes” and

PI&E. Finally, it is of prime importance that the local

police chief and department have a strong commit- ment to wearing seat belts and enforcing the belt law. Lacking this commitment would severely dilute a project effort and obviate a decent chance of suc- cess, even with all of the above-mentioned factors

in place.

The approach of using a nonsanction seat belt law enforcement program to increase belt use in a community can be an effective intervention, even in a state with a primary enforcement law and a relatively high belt use rate. These types of programs can be performed without huge expense, especially in smaller communities, and a guidebook has been prepared to help choose from many ideas and tailor

an approach (Hunter, Lowrance, and Marchetti 1991). In the current setting of belt laws existing in about 80% of the states in the United States, seat belt law enforcement is most likely the key factor in increasing overall belt use rates. It is vital that law enforcement agency personnel serve as good role models by wearing their belts, as well as be made aware of the importance of seat belt citations. Besides citations, this project has shown that non- sanction forms of seat belt promotion by law en- forcement agencies can also be effective in increas- ing use rates.

REFERENCES

Campbell, B. J. Safety belt injury reduction related to crash severity and front seated position. J. Trauma 27:733-739; 1987.

Campbell, B. J.; Hunter, W. W.; Gemming, M. G.; Stew-

art, J. R. The use of economic incentives and public education to increase seat belt use in a community. Chapel Hill: University of North Carolina Highway Safety Research Center; 1984.

Dussault, Claude. Effectiveness of a selective traffic en- forcement program combined with incentives for seat belt use in Quebec. Health Education Research, 5:217-223; 1990.

Evans, L. The effectiveness of safety belts in preventing fatalities. Accid. Anal. Prev. 18:229-241: 1986.

Hedlund, J. Casualty reductions resulting from safety belt use laws. In: Effectiveness of safety belt use laws: A multinational examination. Washington, DC: U.S. Department of Transportation; 1985.

Hunter, W. W.; Lowrance, J. C.; Marchetti. L. M. Com- munity safety belt programs-a guidebook for law en- forcement agencies. NHTSA Project Number DTNH22-88-Z-05234. Chapel Hill: University of North Carolina Highway Safety Research Center; 1991.

Jonah, B. A.; Grant. B. A. Long-term effectiveness of selective traffic enforcement programs for increasing seat belt use. J. Appl. Psychol. 70:257-263; 1985.

Reinfurt, D. W.; Weaver, N. L.; Hall, W. L.; Hunter, W. W.; Marchetti, L. M. Increased seat belt use through police actions. Chapel Hill: University of North Carolina Highway Safety Research Center: 1990.

Williams, A. F.; Preusser, D. F.; Blomberg, R. D.; Lund, A. K. Seat belt use law enforcement and publicity in Elmira, New York: A reminder campagin. Am. J. Pub- lic Health 77:1450-1451; 1987.