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Suggested Citation:"Chapter 2 - Legislation." National Academies of Sciences, Engineering, and Medicine. 2007. The Impact of Legislation, Enforcement, and Sanctions on Safety Belt Use. Washington, DC: The National Academies Press. doi: 10.17226/23127.
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Suggested Citation:"Chapter 2 - Legislation." National Academies of Sciences, Engineering, and Medicine. 2007. The Impact of Legislation, Enforcement, and Sanctions on Safety Belt Use. Washington, DC: The National Academies Press. doi: 10.17226/23127.
×
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Suggested Citation:"Chapter 2 - Legislation." National Academies of Sciences, Engineering, and Medicine. 2007. The Impact of Legislation, Enforcement, and Sanctions on Safety Belt Use. Washington, DC: The National Academies Press. doi: 10.17226/23127.
×
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Suggested Citation:"Chapter 2 - Legislation." National Academies of Sciences, Engineering, and Medicine. 2007. The Impact of Legislation, Enforcement, and Sanctions on Safety Belt Use. Washington, DC: The National Academies Press. doi: 10.17226/23127.
×
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Suggested Citation:"Chapter 2 - Legislation." National Academies of Sciences, Engineering, and Medicine. 2007. The Impact of Legislation, Enforcement, and Sanctions on Safety Belt Use. Washington, DC: The National Academies Press. doi: 10.17226/23127.
×
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Suggested Citation:"Chapter 2 - Legislation." National Academies of Sciences, Engineering, and Medicine. 2007. The Impact of Legislation, Enforcement, and Sanctions on Safety Belt Use. Washington, DC: The National Academies Press. doi: 10.17226/23127.
×
Page 11
Page 12
Suggested Citation:"Chapter 2 - Legislation." National Academies of Sciences, Engineering, and Medicine. 2007. The Impact of Legislation, Enforcement, and Sanctions on Safety Belt Use. Washington, DC: The National Academies Press. doi: 10.17226/23127.
×
Page 12
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Suggested Citation:"Chapter 2 - Legislation." National Academies of Sciences, Engineering, and Medicine. 2007. The Impact of Legislation, Enforcement, and Sanctions on Safety Belt Use. Washington, DC: The National Academies Press. doi: 10.17226/23127.
×
Page 13

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6As Figure 1 shows, there have been two important phases of safety belt legislative activity in the United States: 1) a period of initial laws, occurring primarily from 1984 through 1992, and 2) a period of primary law upgrades, beginning in 1993 and continuing to the present time. Initial Laws (1984–1992) The first SBU law in the United States was enacted in New York in 1984 and, while nearly all subsequent laws were influ- enced by the efforts of an automobile industry-funded lobby- ing organization called Traffic Safety Now (TSN),10 the New York law resulted from the lobbying efforts of a coalition led by the medical community. The New York law allowed for standard/primary enforcement procedures, whereby an offi- cer could stop a vehicle upon observation of a safety belt vio- lation. However, the second law, enacted in New Jersey in 1985, required that a police officer must first observe another law violation before stopping and/or issuing a ticket for safety belt nonuse. This requirement established a new variable in efforts to increase SBU: the issue of primary (standard) enforce- ment laws versus secondary enforcement laws. There have been scores of studies of the impact of early SBU laws in terms of increasing SBU among motorists and crash victims and reducing deaths and injuries. Most studies examined laws implemented from 1984 through 1987. Studies of observed usage included several series of statewide proba- bility surveys, such as those conducted in New York (Rood, McCartt, Kraichy and Carman, 1987); in Michigan (Wagenaar and Wiviott, 1986); and in North Carolina (Reinfurt, Campbell, Stewart, and Stutts, 1990). They also included independently conducted, large-scale convenience surveys11 in New York, Illinois, Texas, and New Jersey (Williams, Wells, and Lund, 1987) and a large multistate study of statewide survey results (e.g., Campbell, Stewart, and Campbell, 1987). In addition to these mostly state-based surveys, NHTSA conducted a comprehensive series of observational surveys in 19 U.S. cities from the late 1970s through 1991, to monitor the impact of safety belt laws across the nation.12 Overall, these studies indicated that early SBU laws were associated with a median increase in usage of about 32 per- centage points, from a baseline of 16% to 18% to a post-law rate of just under 50%. Some laws resulted in larger initial in- creases, to rates above 60%, followed by declines to just under 50%. On the other hand, usage in some states increased more gradually, such as when the implementation of penalties was delayed. C H A P T E R 2 Legislation 11A convenience survey is a survey that is not based upon a probability sample of travel in the jurisdiction examined. Although not probability based, many convenience surveys were extensive and comprehensive in nature, involving several thousand observations at hundreds of sites chosen to represent different driving conditions. 12The 19-cities data were collected in a series of studies. Data collected prior to 1983 were from surveys conducted by Opinion Research Corp. and reported by Phillips (1980, 1983). Data collected from 1983 through 1991 were from surveys conducted by Goodell Grivas, Inc. They included the following years of data and reports: 1983 use rates (Perkins, Cynecki, and Goryl, 1984); 1984 use rates (Goryl and Cynecki, 1985); 1985 use rates (Goryl, 1986); 1986 use rates (Goryl and Bowman, 1987); 1987–88 use rates (Bowman and Rounds, 1988 and 1989); and 1989–91 use rates (Datta and Guzek; 1990, 1991, and 1992). 10This action was in response to a compromise solution to the automatic restraint-SBU controversy that had continued in the United States for about 15 years (1969 through 1984). This compromise was issued in a revised FMVSS (FMVSS 208) that required automobile manufacturers to install automatic restraints in all new passenger cars by the 1990 model year, unless two-thirds of the nation’s population was covered by manda- tory SBU laws by 1989. Such laws had to conform with certain criteria, such as requiring use among drivers and front seat passengers, provid- ing for a minimum fine ($25) and few waivers, providing for prevention and education programs, and requiring that violations could be used to mitigate damages sought by a nonuser injured in a crash.

7SBU legislative activity appears to have initiated a time- related effect that resulted in increased SBU in nonlaw states as well as in law states. This suggestion is based upon an ex- amination of statewide survey data and data from 19 cities, which indicated that the trend was not evident prior to legis- lation, was greatest during the period of the most intense leg- islative activity, and subsided when legislative activity declined (Nichols and Jones, under review). Findings Relevant to Current Efforts to Increase Usage Relevant to current efforts to increase SBU, early evalua- tions consistently showed that the impact of primary (stan- dard) enforcement laws was greater than that of secondary enforcement laws, particularly when enforcement and/or sanctions were in place. Data from the 1987 Campbell report showed a 38-point increase in primary-law states when en- forcement and/or sanctions were in place and an increase of just over 20 points under all other conditions (in primary law states without a penalty in effect and in secondary law states, with or without a penalty in effect). Post-law usage in primary law states was generally 10 to 15 points higher than in secondary law states. In addition, there is consistent evidence that initial safety belt laws impacted low-risk motorists (women, adults, occu- pants of newer vehicles, daytime motorists, nondrinking drivers, and nonspeeders) to a greater extent than it affected high-risk motorists (men, young drivers, occupants of older vehicles, nighttime motorists, drinking drivers, and speeders.) Nearly all studies found post-law usage to be greater among lower-risk groups than among higher-risk groups. In New York, for example, three successive studies found that while bar patrons, young males, and speeding drivers (respectively) increased their SBU following implementation of the state’s SBU law, their increases were nearly always smaller than those observed among community controls and/or lower-risk groups (Preusser et al. 1986, 1987, 1988). Further, as a result of the bar patron study, it was suggested that nighttime en- forcement of safety belt laws should be considered in order to affect higher-risk drivers. Such efforts would address two priority traffic safety issues, safety belt nonuse and alcohol- impaired driving. Because of greater impact on lower-risk groups than on higher-risk groups, initial laws generally resulted in increased differences (in usage) between these two groups. Usage Among Crash-Involved Occupants Similar changes were found among occupants involved in serious crashes. Pre-to-post law comparisons reported by Winnicki (1995) showed that the largest increases in usage among persons in potentially fatal crashes (UPFC)13 were in primary-law states where enforcement and/or sanctions were in effect within 4 months after law implementation (median increase = 21 points). Regression analyses found SBU laws to be associated with a 29% increase in UPFC, with an additional 13% increase associated with primary laws. As was the case in studies of observed usage, lower-risk groups experienced greater increases than high-risk groups. Impact on Fatalities and Injuries The results of individual and multi-state studies showed a median 9% reduction in fatalities and a median 13% reduc- tion in serious injuries associated with initial SBU laws, gen- erally confined to occupants covered by the laws. These find- ings are based on reviews by the U.S. General Accounting Office (1992) and the Centers for Disease Control and Pre- vention (CDC) (Dinh-Zarr, Sleet, and Shults, et al., 2001). Results from multistate studies are shown in Figure 2. The median fatality reduction in these larger studies was 7%. 13Occupants involved in potentially fatal crashes constitute a hypotheti- cal population that includes an estimated number of restrained persons who were saved by SBU, plus those restrained and unrestrained persons who were killed. UPFC is based on usage among fatally injured occupants of passenger vehicles and the estimated effectiveness of safety belts in reducing fatal- ities. UPFC is calculated according to the following formula: UPFC = [uf / (1-e)]/[(uf /(1-e) − (1-uf)]; where uf = use among fatally injured oc- cupants (unknowns excluded); and e = the effectiveness of safety belts in reducing fatalities. A second approach for estimating UPFC is to calcu- late lives saved, using the formula (number of restrained deaths × E (effectiveness))/(1 − E); and then calculating UPFC as follows: UPFC = (restrained occupants killed + restrained occupants saved)/total occupants involved in potentially fatal crashes (i.e. restrained occupants killed + restrained occupants saved + unrestrained occupants killed). At the time of Winnicki’s study, effectiveness (E) was estimated to be 0.45. Estimates now vary by vehicle type and seating position. Using the 2005 proportions of deaths involving various combinations of vehicle type and seating position, along with estimates of effectiveness for each combination (e.g., car/front = 0.45; car/rear = 0.44; LTV/front = 0.60; LTV rear = 0.73), the overall effectiveness of safety belts was estimated to be 0.52 (see Appendix A). -5.8 -6.3 -7.4 -8.7 -7.0 -10 -8 -6 -4 -2 0 Hoxie (1987) Campbell (1987) Partyka (1987) Skinner (1989) Wagenaar (1988) % D ec re as e in D ea th s Figure 2. A summary of the impact of early safety belt laws on fatalities: Results of multi-state studies (adapted from Nichols and Jones, under review).

8Reductions in deaths were smaller than expected, based upon the magnitude of changes in observed usage and the es- timated effectiveness of safety belts in reducing deaths in po- tentially fatal crashes.14 Williams and Lund (1988) estimated that, given the change in observed use and the estimated ef- fectiveness of safety belts, reductions should have been about 15%. The smaller-than-expected impacts likely reflected the fact that observed (daytime) usage did not accurately reflect usage among occupants involved in serious crashes. Several studies have reported that: a) decreases in fatalities were greater in primary law states than in secondary law states [U.S. Government Accounting Office (GAO), 1992, and Dinh-Zarr, Sleet, Shults, et al., 2001]; b) reductions were greater in the first few months following law implementation than in later months (e.g., Skinner and Hoxie, 1989; Skinner, 1989); and c) the impact on fatalities and injuries was greater among low-risk groups than among high-risk groups (Wagenaar and Wiviott, 1986; Williams, Wells, and Lund, 1987; Rood, McCartt, Kraichy, and Carmen, 1987; and Winnicki, 1995). Primary Law Upgrades (1993–2006) While informative, the outcomes associated with initial SBU laws are less important today than they were two decades ago. Recent efforts to enact primary-law upgrades are more relevant to current efforts to increase SBU and to reduce the fatalities, injuries, and costs associated with motor vehicle crashes. In spite of the fact that early research showed standard/primary enforcement laws to be more effective than secondary laws, only nine states (and Puerto Rico) had primary laws in effect by the end of 1992. Thirty-two states (and the District of Columbia) required secondary enforcement procedures. This situation has changed in recent years as upgrades have been implemented in 17 states and the District of Columbia. Eleven of these upgrades, implemented from January 1993 through January 2007 (see Figure 3),15 have been evaluated. Table 1 summarizes the results of these evaluations. It shows a 16-point median increase in observed SBU. Using only the me- dian outcome from three California studies (+18 points) and one of two identical outcomes for Michigan, the median in- crease is 15 points.16 Smaller gains were associated with more re- cent upgrades (median = 11 points) than with earlier upgrades (median = 16 points), likely associated with higher baselines. It is important to note that several primary-law upgrades were complemented by intensified enforcement and public- ity. The upgrades in Maryland and Oklahoma were preceded and followed by participation in statewide Chief ’s Challenge incentive programs,18 and nearly all of the recent upgrades were complemented by participation in national Operation ABC or CIOT enforcement mobilizations (in Michigan, New Jersey, Washington, Delaware, and Illinois).19 Thus, in 1 1 1 3 1 1 2 1 2 1 1 2 1 0 1 2 3 4 '93 '94 '95 '96 '97 '98 '99 '00 '01 '02 '03 '04 '05 '06 '07 N um be r o f L aw s More Recent UpgradesEarly Upgrades Figure 3. Primary law upgrades implemented by year, from January 1993 through January 2007.17 14Effectiveness at the time was estimated to be 45% (against deaths). Currently, effectiveness is estimated to be 45% among front seat occu- pants and 44% among rear seat occupants of passenger cars and 60% among front seat occupants and 73% among rear seat occupants of light trucks and vans (LTVs). The 2005 distribution of these vehicle type/ seating combinations in potentially fatal crashes was approximately 52%, 5%, 38%, and 5%, respectively (see Appendix A). 15These upgrade jurisdictions include: California (1993); Louisiana (1995); Georgia (1996); Maryland, Oklahoma, and the District of Columbia (1997); Indiana (1998); Alabama (1999); Michigan and New Jersey (2000); Washington (2002); Delaware and Illinois (2003); Tennessee (2004); South Carolina (2005); Mississippi and Alaska (2006); and Kentucky (2007). 16A comparison of state-reported observed usage in the calendar year prior to implementation with usage in the calendar year after imple- mentation for 14 upgrade states (for which such data were available re- sulted in a median 13-point increase, with pre-2000 upgrades associated with a larger increase than more recent upgrades (medians: 14 points and 11.5 points, respectively). 17Note that this figure includes the 1997 upgrade in the District of Columbia. 18Chiefs Challenge programs were incentive/reward programs to en- courage police agencies to participate in intensified, coordinated, and publicized safety belt enforcement efforts. 19Operation ABC and CIOT mobilizations were coordinated enforcement and publicity programs organized by the Air Bag and Seat Belt Safety Cam- paign (ABSBSC), NHTSA, and State Offices of Highway Safety. These mobilizations, originally implemented in May and November of each year and more recently only in May of each year, resulted in increased citations for safety belt violations; significant increases in public aware- ness of SBU, laws, and enforcement; and increases in observed usage.

at least half of these jurisdictions, changes in usage were as- sociated with the upgrades in combination with highly visible enforcement. However, increases in usage in years immedi- ately preceding these law changes were nearly always smaller than in postupgrade years, suggesting that the law changes were important factors in the acceleration of usage gains. Another important finding is that primary law upgrades frequently impacted high-risk groups as much as (or more than) lower-risk groups. The impact on young males, occu- pants of pickup trucks, rural motorists, minority groups, and drinking drivers was frequently as great as (and sometimes greater than) on less risky occupants. Thus, while initial laws nearly always increased the usage gap between low-risk and high-risk groups, upgrades often decreased that gap.20 Impact on UPFC Consistent with the above findings, primary law upgrades have nearly always resulted in significant increases in usage among occupants killed (FARS use) and UPFC. Table 2 shows an average 8-point increase (in both measures) associated with 14 upgrades.21 Increases following more recent upgrades22 were slightly greater (+10 points among victims) than those fol- lowing earlier upgrades (+7 points among victims).23 Average changes in UPFC for recent and early upgrades were 9 points (see Figure 4) and 8 points, respectively. Impact on Deaths, Injuries, and Associated Costs (based on UPFC) Based upon changes in UPFC and the estimated effective- ness of safety belts against deaths and injuries (by vehicle type and seating position), it is possible to estimate the impact of law upgrades on these outcomes. Further, based upon ratios of serious injuries to deaths, nationally and in individual Chg. Rank Primary Author (Year) State Baseline (%) Postlaw (%) Change (Points) Sample (Time Period) 1 Lange (1998) CA (’93) 73 96 +23 2 cities (4 yr) 2 Solomon (2001) MD (’97) 72 92 +20 3 counties (2 yr) 3 Chaudhary (under review) AL (’99) 52 71 +19 Statewide (2 yr) 4 Ulmer (1994) CA (’93) 58 76 +18 6 cities (1 yr) 5 IIHS (1993) CA (’93) 53 70 +17 5 cities (1 yr) 6.5 Preusser (1997) LA (’95) 52 68 +16 5 cities (21 mo) 6.5 Solomon (2001) OK (’97) 53 69 +16 3 counties (2 yr) 8 Chaudhary (under review) NJ (’00) 63 78 +15 Statewide (2 yr) 9.5 Eby (2001) MI (’00) 65/70 82 +12/+17 Statewide (2 yr)1 9.5 Chaudhary (under review) MI (’00) 65/70 82 +12+17 Statewide (2 yr)1 11 Solomon (2001) DC (’97) 67 80 +13 Subsample (2 yr) 12 Salzberg (2004) WA (’02) 83 95 +12 Statewide (2 yr) 13 Illinois DOT (2004) IL (’03) 76 86 +10 Statewide (2 yr) 14 Ulmer (1997) GA (’96) 64 72 +4/+8 5 cities (20 mo) Median Change +16 points 1 Note: Data for both Michigan studies come from surveys conducted by Eby et al.; official rates for two pre- upgrade years were 70%, but a survey conducted just before the upgrade found a rate of 65%. Table 1. Change in observed SBU rates associated with primary law upgrades: Outcomes from 10 studies and reports, ordered by magnitude of effect (from Nichols and Jones, under review). 9 20Following our initial review, a study of law upgrades found an im- pact on nighttime usage as well as on daytime usage. In Michigan and New Jersey, the impact was greatest on nighttime usage (Masten, 2007). A study by Voas et al. (in press) reports similar findings with regard to greater impact on usage among drinking drivers than among nondrinking drivers in some states (e.g., in California, Michigan, and Washington). 21It is not clear why Maryland and the District of Columbia did not ex- perience larger immediate increases associated with their laws. How- ever, Maryland had the highest baseline rate of any upgrade state and UPFC increased in subsequent years in both jurisdictions. 22“More recent” upgrades were implemented after November 1998 (from Alabama through Tennessee). 23The average increase for earlier upgrades was largely due to Maryland and the District of Columbia, which had either no increase or a very slight increase. Maryland had the highest baseline usage (among victims and among occupants involved in fatal crashes) of any of the early up- grade jurisdictions.

10 states, and on the findings of studies of the economic costs of crashes,24 it is possible to estimate the cost savings associated with such interventions. If changes in SBU are known (observed or among occupants killed), impact on fatalities, injuries, and costs can be estimated using NHTSA’s BELT USE software, which is part of the agency’s Motor Vehicle Safety (MVS) software package, avail- able on its Web site (www.nhtsa.dot.gov.people/crash/MVS/). This program translates actual or projected changes in SBU into changes in UPFC (by combinations of vehicle type and seating position) and estimates impact on deaths, injuries, and 47 63 55 63 53 55 52 510 19 12 577 0 20 40 60 80 100 AL (1999) MI (2000) NJ (2000) WA (2002) DE (2003) IL (2003) TN (2004) State (Year Upgrade Implemented) UP FC (% ) Pre-Law Baseline Post-Law Change Figure 4. Baselines and changes in usage among UPFC: Seven upgrades implemented since 1999 (change from calendar year prior to upgrade to calendar year after upgrade, based on FARS). Jurisdiction Year Law in Effect FARS Use Prelaw Year (%) FARS Use Postlaw Year (%) Change in FARS Use (points) UPFC Prelaw Year (%) UPFC Postlaw Year (%) Change in UPFC (points) CA 1993 34 47 +14 51 65 +14 LA 1995 24 36 +12 40 55 +14 GA 1996 28 32 +5 44 50 +5 OK 1997 22 29 +6 37 46 +8 DC 1997 27 28 +1 41 42 +1 MD 1997 53 53 -1 69 69 -1 IN 1998 31 41 +10 48 59 +11 Early Upgrade Ave. FARS Use +7 UPFC +8 AL 1999 30 36 +6 47 53 +7 MI 2000 45 53 +8 63 70 +7 NJ 2000 37 41 +5 53 58 +5 WA 2002 45 58 +14 62 74 +12 DE 2003 35 55 +21 51 71 +20 IL 2003 37 48 +11 54 65 +11 TN 2004 35 39 +4 52 57 +5 Recent Upgrade Ave. FARS Use +10 UPFC +9 Overall Ave. Changes FARS Use +8 UPFC +8 UPFC = (number victims belted + number saved) (number victims belted + number saved + number victims unbelted Number Saved = (number victims belted * Effectiveness) (1-Effectiveness); Both calculated by vehicle type and seating position (See Appendix A for example) Table 2. Change in usage among occupants killed and involved in potentially fatal crashes: Calendar year before upgrade to calendar year after upgrade. Source: FARS, 1993–2005 (all numbers rounded to nearest full percentage point). 24NHTSA has conducted several studies of the economic costs of crashes. Four such reports provide cost estimates for the following years: 1980 (NHTSA, 1983); 1990 (Blincoe and Faigin, 1992); 1994 (Blincoe, 1996); and 2000 (Blincoe, Seay, Zaloshnja, Miller, Romano, Luchter, and Spicer, 2002).

costs. Economic savings are based on data from the most re- cent NHTSA economic costs reports.26 Table 3 shows that an estimated 252 deaths and 4,192 Max- imum Abbreviated Injury Scale (MAIS) 2–5 injuries27 were prevented in the first full calendar year after implementation in seven recent upgrade states. Based on this approach, there was an estimated 4.9% reduction in deaths and a 6.1% re- duction in MAIS 2–5 injuries associated with these upgrades. Cost savings totaled about $965 million (expressed in 2007 dollars), for an average of about $138 million per state.28 The estimated savings per death prevented was about $3.8 million (including the savings associated with about 17 MAIS 2–5 in- juries prevented for each death prevented). Impact Based on Study Results Regarding Upgrades Studies that have examined the impact of standard/primary law upgrades using time series or other statistical analyses have reported outcomes that have been considerably larger than those shown in Table 3. Farmer and Williams (2004), for example, found a 7% reduction in passenger vehicle driver deaths associated with 10 upgrades that were implemented from 1993 through 2003.29 They estimated that these up- grades prevented 2,990 driver deaths over an 11-year post-law period. In addition, known ratios of injuries to deaths suggest that nearly 55,000 MAIS 2–5 injuries were prevented.30 On an annual basis, Farmer and Williams estimated that 421 driver deaths would be prevented annually in these juris- dictions (an average of about 42 per jurisdiction). Again, na- tional injury-to-death ratios suggest that 7,631 serious injuries would also be avoided annually (about 760 per jurisdiction). Reductions of this magnitude translate to approximately $1.8 billion in annual cost savings, or about $180 million per jurisdiction, expressed in terms of 2007 dollars (just over $4 million per death prevented). These savings are roughly 30% greater than the average savings shown in Table 3. In another study, Chaudhary and Solomon (under review) found a median 8% reduction in passenger vehicle front-seat 11 State Baseline Usage Among Fatals (%) Usage Among Fatals After Upgrade (%) Deaths Avoided (#) MAIS 2-5 Injuries Avoided (#) Savings Assoc. with Deaths Avoided ($ million) Savings Assoc. with Injuries Avoided MAIS 2-5 ($ million) Savings Assoc. with Deaths & Injuries Avoided MAIS 2-5 ($ million) AL 29.9 35.9 40 325 40 40 80 MI 45.1 53.3 56 897 69 137 206 NJ 36.5 41.3 16 508 24 95 119 WA 44.8 58.3 44 958 61 165 226 DE 34.8 55.2 12 206 15 33 48 IL 37.0 47.6 53 944 66 145 210 TN 34.6 39.0 31 354 31 45 76 Total n/a n/a 252 4,192 $306m $660m $965m Ave. 37.5 47.2 36 599 $44m $94m $138m Table 3. Estimated impact of seven recent primary law upgrades based on actual changes in SBU among fatal crash victims and on estimates provided by NHTSA’s BELT USE software.25 25Total passenger vehicle fatalities for each baseline year were distrib- uted by vehicle type and by seating position, using the 2003 proportions for each state. 26Currently, the data in BELT USE is from 2003 FARS files and eco- nomic costs are stated in terms of 2004 dollars. However, available data for any given year can be entered into the program and cost savings can be translated into data for such years (or for 2007) using economic in- dices such as the Consumer Product Index (CPI), which is available on the Bureau of Labor Statistics (BLS) Web site (www.bls.gov/cpi/). 27MAIS stands for Maximum Abbreviated Injury Scale. It classifies in- juries on a scale of 1 to 5, with MAIS 1 being a minor injury and MAIS 5 being the most serious injury. Safety belts are most effective in reduc- ing moderate-to-serious injuries and deaths. 28In addition to the cost savings associated with deaths and MAIS 2–5 in- juries avoided, there was an additional 2.9% in savings associated with minor injuries avoided (MAIS 1), bringing total cost savings to just under $1 billion, or about $142 million per state expressed in 2007 dollars. 29The jurisdictions examined by Farmer and Williams included Califor- nia, Louisiana, Georgia, the District of Columbia, Maryland, Oklahoma, Indiana, Michigan, New Jersey, and Washington. 30This estimate is based on data shown in Appendix E, which includes estimates of unit costs for deaths and MAIS 2–5 injuries, as well as the (nationwide) ratio of such injuries to deaths. These estimates are based on data derived from three NHTSA studies of the economic costs of crashes, which provide cost estimates for the following years: 1990 (Blincoe and Faigin, 1992); 1994 (Blincoe, 1996); and 2000 (Blincoe, Seay, Zaloshnja, Miller, Romano, Luchter, and Spicer, 2002). From these reports, estimates of costs and number of injuries per death were derived for the four base years and then interpolated for all other years. Given an estimate of deaths prevented (from a reviewed study), the number of MAIS 2–5 injuries and the unit costs for deaths and for MAIS 2–5 injuries were calculated (and adjusted for the greater effec- tiveness of safety belts against injuries than against deaths). The com- bined costs per death and associated injuries were then multiplied by the reported number of deaths prevented.

occupant deaths in three upgrade states (Alabama, Michigan, and New Jersey) from 2000 through 2003. This translated to about 254 deaths prevented in these jurisdictions in 2003, an average of about 85 deaths per jurisdiction. Using state- specific injury-to-death ratios and economic cost estimates from NHTSA’s BELT USE software, the researchers estimated that nearly 4,000 MAIS 2–5 injuries were also prevented, an average of about 1,350 per jurisdiction, and that the total cost savings was more than $800 million, about $302 million per jurisdiction (in terms of 2007 dollars). This is roughly twice the average annual savings shown in Table 3.31 However, the average savings per death (and associated injuries) prevented was about $3.6 million, similar to the $3.8 million per death represented by the data shown in Table 3. Finally, Salzberg and Moffat (2004) reported a 13.4% re- duction in motor vehicle occupant deaths during a 12-month postupgrade period in Washington state. This translated to the prevention of approximately 72 deaths over that period, com- pared with an estimated 44 deaths prevented using the BELT USE software. Based on a relatively high ratio of injuries to deaths in Washington (about 22:1), it was estimated that, if 72 deaths were prevented, more than 1,500 MAIS 2–5 injuries would also have been prevented during the 12-month period and that savings would have totaled nearly $350 million (in 2007 dollars). This estimate is about 60% greater than the esti- mated savings shown in Table 3 for the Washington upgrade.32 12 State Usage Among Fatals in 2005 (%) Usage Among Fatals After Upgrade (%) Deaths Avoided (#) MAIS 2-5 Injuries Avoided (#) Savings Assoc. with Deaths Avoided ($ m) Savings Assoc. with Injuries Avoided MAIS 2-5 ($ m) Savings Assoc. with Deaths & Injuries Avoided MAIS 2-5 ($ m) Savings Assoc. with Deaths & Injuries Avoided MAIS 1-5 ($ m) AZ 39.4 49.1 45 561 51.1 79.2 130.4 133.1 AR 32.2 41.9 37 404 33.6 46.0 79.5 81.5 CO 42.9 52.6 30 384 38.9 61.8 100.7 103.0 FL 40.6 50.3 145 2,083 166.8 298.2 465.0 477.1 ID 42.7 52.4 15 134 16.2 18.0 34.2 34.9 KS 32.8 42.5 24 261 26.8 36.3 63.1 64.6 ME* 42.9 52.6 8 122 9.1 17.2 26.3 27.0 MA 32.9 42.6 19 743 30.3 146.3 176.6 183.5 MN 46.6 56.3 27 325 35.2 50.0 87.2 89.2 MO 33.8 43.5 69 870 75.7 118.5 194.1 199.3 MT 26.7 36.4 15 128 15.3 16.0 31.3 32.0 NE 31.9 41.6 17 305 17.7 39.7 57.4 59.1 NV 46.7 56.4 18 253 24.5 41.6 66.1 67.6 NH 30.1 39.8 7 160 9.8 26.6 36.4 37.7 ND 25.0 34.7 7 64 7.4 8.2 15.7 16.0 OH 41.8 51.5 62 1,572 68.3 215.0 282.9 292.2 PA 36.7 46.4 75 1,180 86.1 169.0 254.8 262.3 RI 35.1 44.8 4 98 4.9 16.7 21.6 22.4 SD 26.2 35.9 11 98 11.3 12.8 24.1 24.7 UT 44.6 54.3 16 227 16.0 29.0 45.0 45.9 VT 48.0 57.7 3 16 3.6 2.3 5.9 6.0 VA 34.9 44.6 48 775 58.3 116.6 175.0 180.1 WV 37.8 47.5 19 217 17.3 24.8 42.2 43.2 WI 38.1 47.8 41 617 46.8 86.9 133.7 137.4 WY 34.1 43.8 10 65 11.2 8.9 20.2 20.5 Sum n/a n/a 772 11,662 $882 m $1,687 m $2,569 m $2,640 m Ave 37.0 46.7 31 466 $35 m $67 m $103 m $106 m * Maine has since enacted a primary law upgrade but no impact data are available. Table 4. Estimated impact of future standard/primary law upgrades based on an estimated 9.7 percentage point increase in usage among fatal crash victims and from outcomes from NHTSA’s BELT USE software.33 31These greater savings are due primarily to the larger number of (esti- mated) deaths prevented, using the time series procedure. However, some of the differences result from the larger average jurisdiction size in the Chaudhary study. 32A fourth study (Voas, Fell, Tippets, and Blackman, et al., in press) re- ported a median 15% reduction in alcohol-related deaths and a median 5% reduction in non-alcohol-related deaths in five case study states that implemented primary law upgrades. This study found significant im- pact on usage (and deaths) among drinking drivers, which, in some cases, was greater than the impact on nondrinking drivers. This study supports suggestions in the literature that high-risk motorists are af- fected by standard/primary law upgrades and it is consistent with the findings of Eby et al. (2002) and Masten (2007). 33Total passenger vehicle fatalities in 2005, including unknowns, were dis- tributed by vehicle type and by seating position for the BELT USE program.

Unlike the situation with initial safety belt laws, where time series analyses generally found lower impact (median: −9%) than would be expected based on changes in usage (about −15%), the few studies of law upgrades have gener- ally found a greater impact on deaths (median: −8%) than would be expected based on changes in usage (median: −4%). The factors associated with this difference are not clear and it could be that additional studies of upgrades will find smaller impacts on deaths. Potential Impact of Future Upgrades Of greatest current relevance is the potential impact of fu- ture upgrades. Using the median increase in usage among fatally injured occupants in seven recent upgrade states (+9.7 percentage points) and the BELT USE program, Table 4 provides estimates of reductions in deaths, injuries, and costs associated with future upgrades. These estimates use 2005 FARS data (disaggregated by vehicle type and seating position) for baseline or current year status. These estimates suggest that 772 deaths and 11,662 MAIS 2–5 injuries would be prevented annually if the states in- cluded in this list of secondary-law (or no-law) states (as of February 2007) enacted and implemented primary enforce- ment law upgrades.34,35 The estimated savings associated with deaths and MAIS 2–5 injuries prevented would be approximately $2.6 billion per year, or just over $100 million per year, per state (in 2007 dollars). This translates to a savings of about $3.3 million for each death (and about 15 MAIS 2–5 injuries) prevented. Summary of Legislation • Studies of legislation have consistently shown increases in SBU and reductions in fatalities, injuries, and costs associ- ated with motor vehicle crashes. • Recent primary law upgrades appear to impact high-risk groups to a greater extent than did initial SBU laws. This may be due to a greater deterrent value of primary law up- grades or it may be due to the fact that upgrades have been implemented at higher baseline usage rates, thus affecting higher-risk occupants. • On average, recent upgrades have been associated with an 11 percentage point increase in observed daytime SBU; a 9.7 point increase in usage among occupants killed; and a 9.3 point increase in UPFC. • Based on changes in usage among fatally injured occupants, there was an average 4% to 5% reduction in deaths and a 6% reduction in MAIS 2–5 injuries associated with these law changes. Cost savings associated with such changes would average about $138 million per state, with an estimated sav- ings of about $3.8 million per death (and 17 MAIS 2–5 in- juries) prevented. • Studies of upgrades have reported larger impacts, with a median 7% to 8% reduction in deaths. Annual savings as- sociated with these larger impacts range from $175 million to $350 million per state per year, with savings per death prevented of $3.6 million to $4.2 million (in 2007 dollars). • Using the more conservative approach, based upon past changes in usage among fatally injured occupants, a current secondary law state that upgraded to allow for primary en- forcement would, on average, experience 6% fewer deaths and 7% fewer MAIS 2–5 injuries annually (among passenger vehicle occupants). The average estimated savings associated with these reductions would be approximately $2.6 billion per year, or just over $100 million per state per year (in 2007 dollars). These savings translate to about $3.3 million per death prevented (along with approximately 15 MAIS 2–5 in- juries prevented). • The presence of sanctions and enforcement affects the mag- nitude of impact, particularly in primary law states. With initial laws, there is greater impact when standard enforce- ment is permitted and when enforcement and/or penalties are in effect. Similarly, with law upgrades, the presence of HVE generally enhances the impact of the law change (and vice versa). • Most studies of the effectiveness of standard/primary law upgrades include the impact of HVE associated with or fol- lowing such upgrades. Thus, results are associated with the combination of activity. 13 34In all states but New Hampshire, which has no adult SBU law, these law changes would be upgrades from secondary enforcement laws. In New Hampshire, it would be a new law and would likely have an impact greater than the 9.7-point estimate, although there are secondary law states with usage among fatalities that is lower than that in New Hampshire. 35In addition to costs associated with deaths and MAIS 2–5 injuries pre- vented, the last column of this table shows total estimated savings asso- ciated with deaths and all injuries prevented (including MAIS 1). Inclu- sion of minor injuries adds 2% to 3% to the estimated savings involving deaths and MAIS 2–5 injuries.

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TRB’s National Cooperative Highway Research Program (NCHRP) Report 601: The Impact of Legislation, Enforcement, and Sanctions on Safety Belt Use explores the effectiveness of mandatory approaches to increase safety belt usage.

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