Benefits of Seat Belt Reminder Systems

Abstract

This study sought to determine whether fitting a more aggressive seat belt reminder system to new vehicles would be cost-beneficial for Australia. While seat belt wearing rates have been observed around 95% in the front seat, non-wearing rates in casualty crashes are as high as 33% among persons killed and 19% among seriously injured occupants. Benefits were computed for three device options (simple, simple-2 and complex) and three introduction scenarios (driver-only, front seat occupants and all occupants). Four levels of effectiveness were assumed, from 10% to 40%, depending on the type of device fitted. Unit benefits were computed assuming a 5% discount rate and a 15yr fleet life. Various industry experts provided the costs. The findings showed that Benefit-Cost-Ratios ranged from 4.0:1 at best (simple device for the driver only) to 0.9:1 for all seating positions. These figures are conservative, given the assumptions made and the discounted human capital methods used.

Australia has played a leading role in promoting seat belt use, principally through government legislation and enforcement. Australian Design Rule 69 (ADR69), mandated to apply from 1995, saw the introduction of a 5sec warning light designed to act as a seat belt reminder system. Despite seat belt wearing rates for front seat occupants being in the vicinity of 95% for the past decade, current non-wearing rates in casualty crashes are as high as 33% of killed occupants and 19% of seriously injured occupants. These statistics reflect the effectiveness of seat belts in preventing injuries as well as the fact that unrestrained drivers are also higher risk takers.

As noted above, current requirements in Australia call for an indicator light on the dashboard to remain on for 5-seconds after ignition to remind the driver to put on his or her seat belt (and presumably to instruct the passengers as well). There is arguably some concern that this is not sufficient to ensure maximum seat belt wearing in Australian vehicles. A study by Bylund and Björnstig (2001) for instance showed no significant difference in seat belt wearing rates in Sweden between those vehicles fitted with a light only reminder and those with no reminders at all.

Several more aggressive devices have been developed in recent years to remind vehicle occupants to buckle up. The Beltminder^™ developed by Ford is one recent example, which comprises a flashing light on the dashboard and a warning tone of reasonable intensity that remain on until the seat belt is fastened (Fay, Sferco & Scott, unpublished). Variants could include an option for the flashing and tone intensity to increase at higher travel speeds. Obviously, the effectiveness of these devices depends on how occupants respond to them. Safety experts argue that those who forget to put on their belts are likely to be the target audience for seat belt reminders, rather than the “hard-core” non-wearers. The Insurance Institute of Highway Safety and Ford have reported increased wearing rates of around 17% for the Beltminder^™ system (from a baseline value of 68%). The European New Car Assessment Program (Euro-NCAP) has announced they intend to provide added point bonuses for cars they assess for crashworthiness if vehicles are fitted with seat belt reminders. The auto manufacturers generally support the introduction of these devices. A study by Fildes, Fitzharris, Koppel and Vulcan (2003) set out to assess the likely benefits and costs of Australia mandating more aggressive seat belt reminder systems than that called for in Australian Design Rule ADR69/00 and these findings are reported in this paper.

METHOD

The benefits of seat belt reminders were computed using the Harm Reduction method developed in Australia by the Monash University Accident Research Centre and used for previous benefit studies for the Department of Transport and Regional Services (MUARC 1992; Fildes, Digges, Carr, Dyte & Vulcan 1995; Fildes, Digges, Dyte, Gantzer & Seyer 1996). Harm is a metric for quantifying injury costs from road trauma and is a function of the number and type of injuries sustained, expressed in terms of societal costs. Costs for these devices were based on component prices provided by the automotive industry.

Design Options

There are a number of options available for a seat belt reminder system, varying from a simple consistent flashing light and tone up to an engine interlock device for persistent non-users. The automobile industry is supportive of a simple system with a focus on reminding those who forget to buckle up, rather than a full interlock system. Euro-NCAP, too, have accepted this philosophy in awarding bonus points to those who include such simple systems in their vehicles.

While there is some conjecture over the level of “aggressivity” required to achieve sizeable improvements in seat belt wearing in Australia with such a high wearing rate already, the findings of Harrison et al (2000) suggests that the biggest problem is forgetting, rather than intentionally deciding not to buckle up. For the purpose of this analysis, three systems were embraced as described below.

SIMPLE 1 – a simple flashing light and tone of 65dB along the lines of that specified by Euro-NCAP. As noted in the section on equipment costs, this would require a buckle switch (and wiring harness) to detect non-compliance and an additional sound generator to produce the supporting tone for the driver with an additional simple presence detector switch on all other seating positions. If the driver (or other passengers when present) fails to buckle up, the system would continually function. It is assumed that this device would run continuously once initiated until the buckle is installed or the ignition is switched off.

SIMPLE 2 – as well as the above, this device includes a speed monitor that intensifies the flashing rate and tone as the vehicle’s speed increases. This would require an additional monitoring device of the vehicle’s speed to initiate the speed intensifier.

COMPLEX – this device has all the same characteristics as the SIMPLE 2 device, but also includes a more sophisticated belt wearing sensor system (includes a reel-out sensor on the inertia-reel) and an “external second phase intervention”. For example, the hazard lights might flash after either a set period of non-compliance and/or a threshold speed level is reached. This is expected to be a more embarrassing option, hence lead to greater compliance.

These three design options range in their degree of intervention from just a reminder to something a little more aggressive for stubborn motorists. While it would be possible to outline many other alternative strategies, these three represent a variety of levels of intervention judged to be sufficient to generate different levels of compliance among users.

Effectiveness of these Units

The only reliable study of likely effectiveness of a seat belt reminder system in increased seat belt wearing was that undertaken by the Insurance Institute of Highway Safety (Williams, Wells & Farmer 2002) on increased compliance with the Beltminder^™ system. Williams reported a 17% reduction in belt non-wearing with this system, based on observational recordings of wearing behaviour in the USA. Turbell and Larsson (1998) estimated that an effective seat belt reminder system would have the potential to reduce the number of fatal injuries by approximately 7000 persons annually in Europe if all occupants used seat belts (they used varying effectiveness rates across European states). Other studies purport to show effectiveness figures for seat belt systems but in many cases are best estimates, based on surveys, focus groups, etc., which may or may not translate into practice with on-road experience.

On the basis of these findings, the effectiveness rates listed in Table 1 were assumed for front seat occupants in Australia for the three reminder systems outlined above. It should be noted that these figures are more conservative than for Ford, given that Australia has such a high seat belt wearing rate in the front seat already and the expected increase in seat belt wearing figures are modest indeed.

Table 1.

Increases in seat belt wearing rates expected.

Reminder Option	Effectiveness Rate	Effectiveness on unbelted Harm1	Increased Wearing Rates1
SIMPLE 1	10%	0.5%	95.5%
SIMPLE 2	20%	1.0%	96%
COMPLEX (30)	30%	1.5%	96.5%
COMPLEX (40)	40%	2.0%	97%

¹Assumes a baseline-wearing rate of 95 percent prior to implementation, common for front seat occupants in Australia. The increases in the rear seat would be greater, given their lessor exposure wearing rates.

Two figures of effectiveness were assumed for the more Complex reminder system. In the previous study (MUARC 1992), a 40% effectiveness rate was assumed for the complex system. While this device will be difficult to ignore, nevertheless, its effectiveness will be dependent ultimately upon the rate of those who deliberately choose not to comply. There is little evidence, however, of their proportion among the unrestrained population and so the benefits of the complex unit were calculated for both a 30% and 40% effectiveness rate.

Implementation Strategy

Previous evidence suggested that various implementation strategies would yield differential benefits for seat belt reminder systems. Thus, three strategies were included here, namely one for the driver only, for all front seat occupants and/or for all seating positions. This could constitute a phased program of implementation for mandating a seat belt reminder system in a typical 2-row passenger car based on high to low exposure. For instance, there is always a driver in a vehicle (100% exposure), a front seat passenger in around 20–25% and a rear seat passenger in 10–12% of frontal crashes (Fildes et al, 1991). Such a program would yield different Benefit-Cost-Ratios (BCRs) and have differential cost implications for vehicle manufacturers.

Euro-NCAP has acknowledged the possibility of such a staged implementation program for seat belt reminder systems by allocating a three-tiered system of allocating seat belt reminder bonus points. These include 1-point for a system targeting the driver only; another point for targeting all front passengers, and a third for all seating positions in the rear. It could be argued that a more differential system could be employed to take account of the Harm benefits across these three seating positions.

HARM BENEFITS & IMPLEMENTATION COSTS

The amount of Harm that could be saved each year in Australia was calculated for unrestrained occupants taking account of their involvement in road crashes and injury outcomes. Harm refers to the frequency of injury by the societal cost of those injuries. It is estimated that the cost of injury in Australia is A$15 billion annually (Bureau of Transport & Regional Economics, 2000). It was important in determining the proportion of Harm likely to be saved by increased seat belt wearing to use data based on airbag crashes as airbags today provide a restraint benefit in themselves (most modern cars sold in Australia are fitted with at least a driver airbag). In addition, crash rates among those restrained and unrestrained in airbag fitted vehicles were compared in NASS statistics (NHTSA 2002), which showed no significant difference in crash severity.

Baseline Harm

The annual number of casualties was taken from ATSB (2002) and injury costs for fatal, serious and other injures from BTRE (2000) published figures based on recent human capital values. Annual Harm estimates were prepared from these figures, which amounted to $8.853billion for all occupants and $1.883billion for those unrestrained. The levels of seat belt wearing among injured occupants for fatal, serious and minor injuries in Australia were obtained from MUARC (1992) and ATSB (2002). These varied from 32.5% for fatalities, 18.5% seriously injured, to 8.6% other injuries. Table A1 in Attachment A shows these figures and the resultant Harm incurred and saved computed from these data. It is estimated that 100% compliance with seat belt wearing would save the Australian community $587million each year. The resultant annual Harm saved when considering the levels of effectiveness and implementation strategies is shown in Table 2.

Table 2.

Likely Harm saved by seating position in Australia.

Seating Position	Percent Harm	Annual Harm1 Saved 100% effective	Effectiveness Rates
			10%	20%	30%	40%
Driver only	67.6%	$397million	$39.7m	$79.4m	$119.1m	$158.8m
Front seat occupants	19.6%	$115million	$11.5m	$23.0m	$34.5m	$46.0m
All occupants	12.8%	$75million	$7.5m	$15.0m	$22.5m	$30.1m
Total Harm	$587million	$58.7m	$117.4m	$176.2m	$234.9m

¹Harm refers to the frequency of injury by the cost of injuries for those unbelted.

Unit Harm

In calculating seat belt reminder Benefit-Cost-Ratios, the annual Harm saved for the total fleet is converted to unit Harm (saving per vehicle) across the life of that vehicle. In Australia, this is traditionally undertaken using discounted human capital costs (Department of Finance 1991).

In other countries (eg; the USA), injury costs involve Willingness-To-Pay estimates, which are noticeably higher and benefits computed using the “Equilibrium Method” which does not discount future savings. Thus, the benefits here are very conservative compared to what other countries would calculate. The method for converting annual Harm to unit Harm is outlined in previous reports (MUARC 1992; Fildes et al 1995, 1996).

Equipment Costs

The costs established for the three design options were based on advice from equipment suppliers¹ and current available prices of equipment (see Table 3).

Table 3.

Cost build-ups for the three seat belt reminder systems.

	Buckle switch + wiring	Presence detector	Sensor on retractor	Wiring to speedo	Wiring to hazards	Best Retail price	Economic cost (no tax)
SIMPLE 1
Driver only	$10	-	-	-	-	$10	$9.09
Front occupant	$20	$5	-	-	-	$25	$22.73
All occupants	$30	$20	-	-	-	$70	$63.64
SIMPLE 2
Driver only	$10	-	$10	$20	-	$40	$36.36
Front occupant	$20	$5	$20	$20	-	$65	$59.05
All occupants	$50	$20	$50	$20	-	$140	$127.30
COMPLEX
Driver only	$10	-	$10	$20	$5	$45	$40.91
Front occupant	$20	$5	$20	$20	$10	$75	$68.18
All occupants	$50	$20	$50	$20	$25	$165	$150

Estimates of economic cost (price less Goods and Service Tax) varied from approximately $9 to $150, depending on the level of technology and the number of seats to be fitted out. These prices were “best estimates” of current technology likely to be required to meet the outcomes sought. It is likely though that when setting up to meet these criteria, manufacturers will find efficiencies and production savings to minimise costs even further (this was alluded to in responses from one vehicle manufacturer detailed in the study report, Fildes et al, 2003). No allowance was included for these savings; hence, again the BCRs would seem to be somewhat conservative. It was assumed that these devices would be fitted as standard equipment in the vehicles in computing the BCRs.

RESULTS

Annual Harm savings were computed for the three- implementation strategies and the four-effectiveness rates for the range of assumptions outlined above and these are shown in Table 4.

Table 4.

Benefit-Cost-Ratios for the three seat belt reminder systems used in this analysis (assuming a 15-year fleet life and 5% discount).

Seating Position	SIMPLE 1 10%	SIMPLE 2 20%	COMPLEX 30%	COMPLEX 40%
Driver only
Unit Harm Benefit	$36.37	$72.75	$109.12	$145.50
Economic Cost	$9.09	$36.36	$40.91	$40.91
Benefit-Cost-Ratio	4.0:1	2.0:1	2.7:1	3.6:1
Annual Harm Saved	0.45%	0.9%	1.35%	1.79%
Front seat occupants
Unit Harm Benefit	$46.92	$93.84	$140.76	$187.68
Economic Cost	$22.73	$59.09	$68.18	$68.18
Benefit-Cost-Ratio	2.1:1	1.6:1	2.1:1	2.8:1
Annual Harm Saved	0.58%	1.16%	1.74%	2.31%
All occupants
Unit Harm Benefit	$53.81	$107.61	$161.42	$215.23
Economic Cost	$63.64	$127.27	$150.00	$150.00
Benefit-Cost-Ratio	0.8:1	0.8:1	1.1:1	1.4:1
Annual Harm Saved	0.66%	1.33%	1.99%	2.65%

These varied from around $40 million to $235 million annually if all vehicles in the fleet were fitted with the devices. This would amount to an annual Harm reduction of between 0.45% and 2.65%. Unit Harm benefits were calculated using three levels of discount factors (4%, 5% and 7%) and two levels of fleet life periods, namely 15 and 25 years. In the light of a recent report by the Bureau of Transport and Regional Economics (BTRE, 2001), it was argued that a 5% discount rate and a 15-year fleet life were the most appropriate for this analysis. On this basis, only this discount rate and fleet life figure will be reported here for the various design options, implementation and the appropriate discount rates and fleet lives as shown in Table 4. Those interested in the full range of BCRs (the sensitive analysis) are referred to the full report (Fildes, Fitzharris, Koppel & Vulcan, 2003).

These figures suggest that a regulation requiring manufacturers to provide a more “aggressive” seat belt reminder system in passenger cars appears to be desirable for Australia. The BCRs calculated for either a simple or a complex device would likely be cost-beneficial for both the driver-only and front seat occupant options (BCRs between 1.6:1 and 2.8:1). While driver-only BCRs were generally highest, the annual Harm savings would be greater if the devices were available for both front seat passengers and best of all for both front and rear seating positions.

DISCUSSION

This study set out to examine the benefits and costs of a more aggressive seat belt reminder system than that currently specified in Australian Design Rule (ADR) 69/00 (a 5-sec timed warning light displayed to the driver). It has been argued that such a warning is lost among the various warning lights that display when the ignition is activated, and that a more persistent warning would lead to improvements in seat belt wearing in Australia. A more “aggressive” reminder system therefore would seem warranted to help further reduce road trauma in Australia.

The Benefit-Cost-Ratios calculated for the various more aggressive design system options and implementation strategies are impressive. BCRs ranged from 4.0:1 to 0.8:1 depending on seating positions included, the complexity of the device, the discount rate for future benefits and the expected life of the vehicle fleet. Best BCRs were for the driver only although front seat passenger BCRS still ranged from 2.8:1 to 1.6:1. While the BCR for the driver-only is greater than for both front-seating positions for all devices, the latter offers an additional 29% reduction in total occupant Harm and still sound BCRs. Furthermore, Net Present Values (NPV, Unit Harm benefit minus economic cost) are much greater for both-front-seat occupant installations. While the benefits in terms of Harm reduction and NPV are even greater for devices fitted in all seating positions, the BCRs are only marginal, apart from those for the complex device at 40% effectiveness. On this basis, it could be concluded that a device fitted for both front seat occupants is likely to yield higher overall benefits in Harm reduction and sound BCRs and therefore would seem to be a preferred option for Australia.

It is important to note that the Benefit-Cost-Ratios found in this study would be much greater if seat belt wearing rates were less than those currently observed in Australia. Furthermore, the use of Willingness-To-Pay injury costs, lower discount rates and extended fleet life periods would also lead to higher BCRs than those reported here.

Effectiveness of These Devices

These calculations are very much dependent upon the effectiveness of the seat belt reminder in generating greater compliance. The figures of likely effectiveness were established based on available U.S. evidence (Williams, et al 2002), varying from 10% for a simple continuous flashing light and auditory signal, up to 40% for a more complex unit (MUARC 1992). This latter device monitors seat belt wearing more accurately and has a two-phase operation, where the second phase intervention aims to embarrass the occupant through a visual external display. It is intended to gain greater compliance among those who steadfastly refuse to buckle up. Even so, two values of effectiveness were computed for the complex device, based on a previous estimate in MUARC (1992) as well as a more conservative estimate (30%).

The effectiveness values were “best estimates” based on the available literature (MUARC 1992: Williams, et al 2002) and were downgraded in this analysis in the light of the high level of seat belt wearing that exists in Australia. Of course, it could be argued that even these modest levels may be difficult to achieve given the high levels of seat belt wearing in this country. However, figures from Europe where seat belt wearing is also quite high claim even greater benefits than those found by Williams in the USA (Bylund & Björnstig, 1996; Turbell & Larsson, 1998). A 10% increase in seat belt wearing represents an exposure increase from 95% to 95.5%, while a 40% increase represents an increase from 95% to 97%. These are not substantial increases by any means, although the projected reductions in serious casualties and death are many times greater. The recent focus-group study by Harrison, Senserrick and Tingvall (2000) argued that up to 80% of non-belt wearers involved (those who had incurred penalties for non-belt wearing) claimed to have forgotten to put their belt on, rather than have a fundamental objection to seat belt wearing. On this basis, the figures used here would seem to be conservative and may well be underestimates of the likely effectiveness of the devices specified.

An associated issue relates to the mitigation of effectives due to disabling or ignoring the reminder signal. These systems are not meant to be interlocks but as their name implies “reminders”. In other words, they are not intended to prevent the car from driving. Of course it would be relatively easy for someone with some technical knowledge to disable the system or for another to drive on ignoring the signal. They are there to simply remind the driver and/or passengers to wear their seat belt. The effectiveness figures assume compliance on the part of only a proportion of drivers (those who will agree to buckle up in the presence of the reminder signal). Again, the Harrison et al (2002) study claims that the figures used here would seem to be achievable in Australia.

Future Savings and Life of the Fleet

The Bureau of Transport and Regional Economics (BTRE, 2001) argued that the discount rate for future savings for a particular project should reflect the opportunity cost of using resources in that project rather than for an alternative means of obtaining equivalent benefits. They noted that the real cost of borrowing funds for the Federal Government during the time period when black-spot treatment expenditure occurred was around 5%. They conducted an evaluation of the effects of different discount rates on future black-spot programs at four varying rates and claimed that that a 5% rate generated the most meaningful results for the reasons discussed above. This report also noted, however, that during the period of the study, the actual 10-year bond rate was between 3 and 4% and even less than the 5% they settled on. While it may be somewhat presumptuous to use government discount rates when discounting for automotive applications, it still represents the best advice based on current bond rates and market economics. Hence, the use of figures computed for a 5% discount rate is appropriate here.

The average age of the Australian fleet is increasing. The current age is around 10.5 years and the distribution is slightly skewed towards older vehicles (ABS, 2002). The age distribution of crashed cars reveal that 75% of casualty crashes involve vehicles aged 15 years or less and 85% approximately 18 years or less. On the assumption that the Australian vehicle fleet age will continue to increase gradually over the coming years, it would seem that the use of a 15-year vehicle fleet age is appropriate for these computations.

Costs of the Devices

The costs established for the three design options were based on advice from equipment suppliers and current available prices of equipment. These prices were again “best estimates” of current technology likely to be required to meet the outcomes sought. It is likely though that when setting up to meet these criteria, manufacturers will find efficiencies and production savings to minimise costs even further. As noted earlier from one international vehicle manufacturer, if a vehicle is equipped with “intelligent airbag systems”, there are switches in the belt buckles and passenger detection systems fitted already that could be used for reminder systems at no cost. No allowance was included for these savings; hence, again the BCRs are again likely to be somewhat conservative.

Standard Equipment and Visibility of the Device

In making these computations, it was assumed that device would be standard equipment on all new passenger cars and not visible to those who normally wear their seat belts. The Benefit-Cost-Ratio calculations assume that the device is fitted to all new passenger cars as standard equipment. If optional, the BCRs would be discounted considerably from what is calculated here. The design options outlined were based on the assumption that a person who normally wears a seat belt would be ignorant of the presence of the reminder device. The SIMPLE options are based on the premise of providing a “reminder” for those who forget to buckle up and so would be effective in generating higher seat belt wearing amongst this group. Some benefit would also be gained from those who do not buckle up on short trips to local destinations and those who only put on their belts outside urban regions.

On the other hand, the COMPLEX device in the early phase would act as a reminder for the forgetful but would also offer some benefit for the hard-core group of non-wearers by embarrassing them into buckling up when they persist in overlooking the reminder. This option was included as Australia has such a high seat belt wearing rate and there is concern that the forgetful users may be only a small proportion of non-users in this country. There is an opinion, especially in Europe, that seat belt reminders should only be simple reminders and not “interlock devices”, given the previous bad experience seen in the U.S. during the seventies. The complex device proposed here stops well short of being an interlock as the car would be quite driveable, even with the hazard lights flashing. However, it would be obvious to other motorists and the authorities that someone in the car is not wearing their seat belt so that appropriate action could be taken to either avoid these motorists or correct this situation through police enforcement.

Euro-NCAP and Harmonisation

Euro-NCAP are planning on providing added bonus points to manufacturers who fit a seat belt reminder to their cars as part of their assessment of a vehicle’s crashworthiness. Their recommended design specification includes a 65dB auditory signal and a visual signal clearly visible to the driver that should be active the entire time that the seat belt on an occupied seat is not on during a journey. This equates to what is principally outlined in the simple and simple-2 systems in this study. Rewards will include a one-point bonus for a driver-only device, another point for both driver and front passenger and a third for devices fitted to all seating positions.

One manufacturer argued that any proposal for a seat belt reminder system in Australia should harmonise with that proposed by Euro-NCAP. While there is great merit in Australia harmonising with overseas requirements generally, given our small share of the international market, it is not clear what the European Parliament’s position is on seat belt reminder systems (Euro-NCAP is not the government regulator of vehicle safety in Europe). It could be argued that as seat belt reminders constitute an add-on feature which do not require major re-engineering of a vehicle, this is an opportunity for Australia to lead the way in terms of what will provide greatest benefits to the Australian and international community.

Conclusion

The findings from this study show that a regulation requiring manufacturers to provide a more “aggressive” seat belt reminder system in Australian passenger cars seems to be appropriate for Australia, even given its current high seat belt wearing rate. On the basis of this analysis, the BCRs calculated for either a simple or a complex device was cost-beneficial for front seat occupants. The preferred strategy would be for the device to be fitted for both front seat occupants and would yield reductions in total occupant Harm each year of up to 2.8%. It is not clear if a simple device (consistent flashing light and warning tone) would be sufficient to guarantee the level of compliance assumed, given the high level of seat belt wearing that exists already in Australia. Hence a more aggressive unit that embarrasses non-wearers may be necessary.

The current regulation for a 5-second reminder light is arguably not sufficient for reminding motorists to buckle up and there are moves afoot in Europe and the U.S. to address this. Vehicle manufacturers are generally supportive of these attempts, although they would like to see some international harmonization of requirements. It could be argued, though, that given that these devices are a simple add-on feature, harmonization is not really a significant issue, and that Australia is well placed to lead the world in providing a device that will reduce trauma on our roads.

Table A1.

Harm to all occupants and those unrestrained in car crashes in Australia in frontal, side impact, rollovers and rear-end collisions by severity of the injury (1996 $A millions). Figures taken from full report in Fildes, Fildes, Fitzharris, Koppel and Vulcan (2003).

SEVERITY OF INJURY	TOTAL ANNUAL INJURED	PROP. CRASH TYPE1	TOTAL PEOPLE INJURED	TOTAL HARM2 $million	UNRESTRAINED3		% HARM SAVED4
					Prop.	HARM $million	Prop	HARM $million
Fatal-front	1368	0.343	469	703	0.325	229	0.38	88.6
Fatal-side	1368	0.276	377	566	0.325	184	0.22	401.
Fatal-roll	1368	0.118	161	242	0.325	79	0.40	31.9
Fatal-rear	1368	0.010	14	20	0.325	7	0.34	2.2
Fatal-other	1368	0.254	347	521	0.325	169	0.34	57.2
Total-Fatal	1368	1.0	1368	2052	0.325	667		220.9
Severe-front	15539	0.424	6583	2140	0.185	396	0.38	153.5
Severe-side	15539	0.207	3224	1048	0.185	194	0.22	42.6
Severe-roll	15539	0.077	1201	390	0.185	72	0.40	29.3
Severe-rear	15539	0.084	1301	423	0.185	78	0.34	26.4
Severe-other	15539	0.208	3230	1050	0.185	194	0.34	65.64
Total-Severe	15539	1.0	15539	5050	0.185	934		317.6
Minor-front	150818	0.412	62206	722	0.086	62	0.38	24.1
Minor-side	150818	0.289	43600	506	0.086	44	0.22	9.5
Minor-roll	150818	0.026	3997	46	0.086	4	0.40	1.6
Minor-rear	150818	0.198	29832	346	0.086	30	0.34	10.06
Minor-other	150818	0.074	11182	130	0.086	11	0.34	3.7
Total-Minor	150818	1.0	150818	1751	0.086	150		49.1
TOTAL HARM				8853		1883		587.21

¹Proportion of injured by crash type derived from figures for Victoria and Qld, 1997–1998.

²Cost of injury in 1996A$ for fatal = $1,500,000, Severe = $325,000 and Minor = $11,611 (BTE, 2000)

³Proportion unrestrained derived from ATSB fatal and non-fatal files and from Fildes et al (1991).

⁴Proportion of Harm likely saved in all seating positions (assuming 100% effectiveness for the reminder system). This comprises $397 million for drivers, $115million for front passengers and $75million for rear passengers, based on current crash involvement figures.