Motorcycle road rider age and risk of fatal injury

The relatively high risk to motorcycle riders of serious and fatal injury, compared with other road users, is a significant road safety issue. Trends in motorcycle fatalities over the decade to 2001 suggest improvement in the safety of motorcyclists has been lagging that of other road users. Motorcycle rider fatalities only decreased by 6 per cent between 1991 and 2001compared with an 18 per cent reduction in the overall road toll, from 2113 to 1736.

Australia’s motorcycle safety record compares relatively poorly with other OECD nations as a whole. In 2000, the latest year for which data are available, there were 5.7 deaths per 10 000registered motorcycles, compared with an OECD median of 5.11. This is significant considering Australia ranks favourably in its overall road safety record. In 2000, there were1.5 fatalities per 10 000 registered vehicles compared with the OECD median of 1.9.

This report examines the trends associated with motorcycle rider fatalities and compares the risk of fatal injury to motorcycle riders among different age groups, particularly older riders. The report only uses data relating to motorcycle operator (rider) fatalities where the rider is aged 17 years and over and where the fatal injury occurred on a public road correlated area. It excludes motorcycle passenger fatalities and cases where age is unknown.

Crash reduction studies of motorcycles

There are reasons for believing that the case for DRL as a countermeasure for motorcycle crashes is even more compelling than that for cars, as cars are more conspicuous than motorcycles. Laboratory studies and field trials have demonstrated that motorcycles equipped with DRL are more easily seen than motorcycles without such equipment.

Studies of causal factors in motorcycle crashes have revealed that crash-involved motorcyclists are less likely to be using DRL at the time of the crash than non-crash involved motorcyclists.

A Californian study on the effects of a law requiring that new motorcycles have DRL fitted revealed no effect on fatalities and a non-significant reduction in vehicle-vehicle daytime crashes. Two studies of the effect of the Australian Design Rule (ADR 19/01) requiring hard-wired DRL on new motorcycles in Australia have been carried out, both finding small but non-significant reductions in crashes. The number of crashes on which these studies were based was too small to conclude that DRL are ineffective.

Two studies from Malaysia and Singapore provide some positive evidence in relation to daytime use of headlights for motorcycles. A national campaign to increase daytime headlight use in Malaysia resulted in an 82% headlight use rate and a reduction in conspicuity-related crashes of 29%. Compulsory headlight use for motorcyclists in Singapore was found to result in a significant reduction in fatal and serious injury crashes.

Rural Road Dividing

Divided roads

The travel time savings if the speed limit were increased to 130 km/h on rural divided roads were estimated to be the same as on freeways, and the percentage change in crash costs would be similar. However the number of additional casualties would be higher because of the higher initial crash rate. Fatal crashes would increase by 3.4 per year per 100 km of divided road. Similar remarks regarding the economic analysis of rural divided roads apply as were made for freeways, except that a simple increase in the speed limit to 130 km/h would have a substantial economic cost ($6.45 million increase per year per 100 km of road). Even higher figures would be estimated with alternative valuations of leisure travel time and road trauma.

The economic loss on divided roads could be overcome to a large extent if trucks were limited to 100 km/h. However a variable speed limit system allowing speeds of 120 km/h under good conditions would not be as beneficial as on rural freeways. There would be an additional 0.3 fatal crashes per year per 100 km of road, but a saving of 2.5 minutes per car travelling over the 100 km section averaged over the whole day. A system allowing 130 km/h on divided rural roads during good conditions would result in greater road trauma levels.

Undivided roads

There is apparently no economic justification for increasing the speed limit to 130 km/h on the two-way undivided roads, especially the lower standard 7.0 m sealed roads without shoulder sealing.
On the straight undivided sections without intersections or towns, total costs on the 7.0 m roads would be increased by $2.04 million per annum per 100 km of road, or almost 10% of current costs. There would be travel time savings of 13.8 minutes per vehicle over 100 km, but an increase of 0.8 fatal crashes per year on the same road section. (The increase in casualty crash costs would be 142%, but the number of additional fatalities and casualties per 100 km road section would be lower than on divided roads because of the lower traffic volumes on typical undivided roads.)

On the lower standard undivided roads through curvy terrain requiring slowing and occasional towns requiring stopping, the average speed would be lower and the travel time savings would be only 9.8 minutes per vehicle over 100 km. The total cost associated with raising the speed limit, and hence the cruise speeds, to 130 km/h is estimated to be $14.78 million per annum per 100 km, due to increased fuel consumption predominantly and to increased air pollution emissions, each associated with the deceleration-acceleration required by slowing and stopping from 130 km/h cruise speed and returning to that speed.

The optimum cruise speed for cars travelling on these roads is estimated to be 100 km/h if the road is straight without crossroads and towns, but only 85 km/h if the road has many sharp bends and includes intersections and towns requiring stopping. The optimum cruise speed for trucks is estimated to be 85 km/h, and no more than 80 km/h on curvy undivided roads of the same standard. Optimum cruise speeds would be somewhat lower if ‘willingness to pay’ values were used for crash costs, or lower values were used for leisure time savings.

On the higher standard, 8.5 m shoulder-sealed undivided roads, an increase in the speed limit to 130 km/h would not result in as many additional crashes as on the lower standard roads, but the total cost would still increase by $1.02 million per annum per 100 km of straight road: about 5% of current total costs. The travel time savings would be the same as on the lower standard undivided roads, but on the straight sections without intersections or towns there would still be 0.5 additional fatal crashes per year per 100 km of road. These calculations assume equal traffic volumes on higher standard and lower standard undivided roads. In practice, traffic volumes are likely to be higher on the better roads, so the number of additional casualties and the net cost increase per section could be higher on these roads.

Again, as with the lower standard undivided roads, the higher standard roads through curvy terrain and passing through towns would experience substantial increases in total social costs associated with the increased speed limit, due to increased fuel consumption and emissions because of frequent deceleration and acceleration. The total cost associated with cruise speeds of 130 km/h on such roads would be $13.65 million per annum per 100 km of road. Travel time savings would be reduced compared with straight 8.5 m shoulder-sealed sections, and fatal crashes would be increased by 0.6 per year per 100 km of curvy road.

The optimum cruise speed for cars travelling on the higher standard undivided roads is estimated to be 105 km/h if the road is straight without crossroads and towns, but only 90 km/h if the road has many sharp bends and includes intersections and towns requiring stopping. The optimum cruise speed for trucks is estimated to be 90 km/h, but only 85 km/h on curvy undivided roads of the same standard.

Community Attitudes to Road Safety

This report documents the findings from the Australian Transport Safety Bureau’s latest survey of community attitudes to road safety. The main purpose of 2003 Community Attitudes Survey (CAS), the sixteenth in the long running survey program, is to monitor attitudes to a variety of road safety issues, evaluate specific road safety countermeasures, suggest new areas for intervention and identify significant differences between jurisdictions.

The in-scope population for the survey was persons aged 15 years and over. Interviewing, using Computer Assisted Telephone Interviewing (CATI) technology, was conducted in March and April 2003. The sample comprised private dwellings across Australia listed in the Electronic White Pages telephone directory. A total of 1,638 interviews were conducted, with an average interview length of 16 minutes. A disproportionate stratified sampling methodology was utilised to ensure adequate coverage of the population by age, sex, state / territory and capital city / other locations. The response rate (completed interviews divided by all contacts excluding away for survey period) was 68%. Almost one in five interviews was conducted as a result of some form of response maximisation activity (refusal conversion, language other than English interview, mail follow up, 9th or more call attempt).