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).

On-Road Evaluation of Perceptual Countermeasures

Speeding has been long recognised as a major factor in the occurrence and severity of road crashes. While enforcement, education/publicity and engineering programs have assisted in reducing speed-related road trauma, supplementary measures to reduce the incidence of unsafe speed behaviours, particularly at hazardous locations, have been sought.

A study was undertaken by Fildes and Lee in 1993 to assess needs for further research and action to reduce excessive speeding. A key outcome of the study, which involved leading experts across Australia, was the need to develop low cost perceptual countermeasures designed to reduce driver speed on roads.

Perceptual countermeasures (PCMs) against excessive speeding refer to manipulations of the road scene presented to a driver that can influence his or her subsequent behaviour. For the most part, these treatments tend to be relatively low cost additions or modifications to the road or roadside setting that can lead to a change in the way the driving environment is perceived by drivers.

The then Federal Office of Road Safety (now Australian Transport Safety Bureau) and the Road and Traffic Authority of New South Wales (RTA NSW) commissioned the Monash University Accident Research Centre (MUARC) and ARRB Transport Research (ARRB TR) to conduct a long-term study of perceptual countermeasure designs and likely effectiveness. A four-phase research program commenced in 1993.

The first stage was a literature review of perceptual countermeasures by Fildes and Jarvis (1994). The second stage of the project was a simulation validation study (Fildes, Godley, Triggs & Jarvis 1997).

The third stage of the project involved the evaluation of a range of PCMs using the driving simulator at MUARC. It was recommended that the effects of the promising treatments from this research be further evaluated on the road to demonstrate the speed reduction benefits, both immediate and longer-term, as well as their safety benefit.

The fourth and final stage of the study (the current stage) involved applying two of the more promising PCM treatments on a sample of mid-block and intersection locations and evaluating their effectiveness and cost-benefits. This report documents the on-road evaluation of two PCM treatments: peripheral transverse lines applied on the approach to intersections and enhanced post spacings with ascending heights applied at road curves.
Study Design

The treatments were applied at six intersections and six curve sites in Melbourne and Sydney. The evaluation study comprised before and after observations of vehicle braking distance, lateral displacement, and speed profile at the treated sites, and then compared these observations and measurements to sites of similar geometric and geographic characteristics which were untreated (i.e. control sites).

The comparison of data enabled the effects of each treatment to be evaluated, both before and after installation, while controlling for traffic differences at the sites. The inclusion of two after evaluation periods at 1-2 months and 12 months after installation allowed the short- and long-term effects to be evaluated separately.
Main Results

At both the curve and intersection treatment sites, the results indicate that the treatments were not uniformly effective at reducing travel speeds, although the long-term results were more promising than the short-term findings. Reductions in average speeds were observed more consistently at intersection sites than at curve sites.
Curves

At the curve sites, the treatment effects immediately after installation were quite mixed, with only two of the six treated sites recording significant speed reductions relative to control sites.

In the longer-term, the PCMs produced relative speed reductions at three of the six sites, and had no effect at two sites. At the other treatment site, road condition changes and damage to the treatment during the study period made the results unreliable.

It was noted that the two sites that demonstrated no effect were better delineated by guideposts than the other sites prior to treatment installation. That is, the treatment appears to have been more effective at sites, which were not delineated, or not well delineated, by guideposts prior to treatment installation. Furthermore, one site was a flatter curve than the others and drivers did not need to slow down much to negotiate it, possibly contributing to its lack of effectiveness.
Intersections

At the intersection sites, the PCMs had more effect on reducing travel speed, relative to the control sites, both short-term and long-term. Speed reductions were observed at a majority of the locations.

An analysis of segment differences between treated and control sites was only partially successful, due to missing data. However, where comparisons were possible, treated intersections showed differences in the speed profile in the approach to the intersection. The results also suggest that while this treatment was expected to have its greatest effect on vehicle speeds in the early stages of the treatment, it is possible that speed reduction effects occurred over the second 200m of the treatment prior to the intersection.

The analysis of braking behaviour and lateral vehicle positioning did not demonstrate any effect of the perceptual treatments at intersections.
Other Findings

The NSW curve and intersection control sites generally demonstrated an increase in average vehicle speed over the long-term study period. Average vehicle speeds increased at four of the six control sites, with no significant changes at the other two control sites. It has not been possible to establish whether or not this was a general trend in NSW over the study period. The treatment sites, on the other hand, all demonstrated no significant change in average vehicle speed over the long-term study period. If there was an overall increasing trend in vehicle speeds in NSW during the study period, it appears that the treatments may have been successful in diminishing the effect at the treatment sites.

Given that the PCMs tended to be more effective in the long-term, it might suggest that drivers need time to accommodate to them and change their driving behaviour. It is noted that, at all of the sites, the majority of traffic was local and most drivers would probably be very familiar with the road.
Recommendations

In light of these results, a number of recommendations might be worthy of consideration.

• For sites that demonstrated a positive long-term effect, conduct further speed surveys approximately 2 years after installation of the treatments, to determine whether the speed reduction effects have been sustained.


• If further surveys of the intersection treatment are to be conducted, then there is a need to record and analyse speed measurements over the entire length of treatment (which would require more than one speed laser gun).


• Compare the detailed results of this study with the previous simulation study (Godley, Fildes, Triggs & Brown, 1999) to determine the differences in actual results and simulator results.


• Identify other perceptual countermeasures, from the previous studies, that could be trialled.


• Further research is warranted targeting locations of high traffic exposure and crashes in urban shopping precincts and school and residential zones. Research needs to evaluate speed reductions as well as crash savings.

Road Deaths Australia, Monthly Bulletin; February 2008

Road Deaths Australia is a monthly bulletin presenting the latest fatal road crash data as well as recent historical comparisons. It is produced by the ATSB using monthly data supplied by the eight states and territories.

• There was a total of 105 road deaths in February 2008.
  - this is a 13.9 per cent decrease from the February 2007 figure.



• There have been 221 road deaths in 2008 to the end of February.
  - this is a 13.0 per cent decrease from the same 2 month period in 2007.

Fatal Heavy Vehicle Crashes Australia; Quarterly Bulletin, January-March 2008

Fatal Heavy Vehicle Crashes Australia is a quarterly bulletin presenting recent data on fatal road crashes involving heavy vehicles as well as historical comparisons. It is produced using data supplied by the eight states and territories.

• During the 12 months to the end of March 2008, 294 people died from 251 crashes involving heavy trucks or buses. These included:


• 183 deaths from 148 crashes involving articulated trucks


• 92 deaths from 85 crashes involving heavy rigid trucks


• 27 deaths from 26 crashes involving buses.


• Fatal crashes involving articulated trucks:


• increased by 4.2 per cent compared with the previous 12-month period


• increased by an average of 5.5 per cent per year over the three years to March 2008.


• Fatal crashes involving heavy rigid trucks:


• increased by 19.7 per cent compared with the previous 12-month period


• increased by an average of 0.1 per cent per year over the three years to March 2008.

Warning device event - 232 kms south of Paraburdoo, Western Australia, VH-NXH, Boeing 717-200

On 28 February 2006, a Boeing Company 717-200 aircraft, registered VH-NXH, was being operated on a scheduled passenger service from Paraburdoo to Perth, WA. The flight was being conducted under the instrument flight rules (IFR). Onboard the aircraft were two flight crew, four cabin crew and 66 passengers. The aircraft departed Paraburdoo at about 0837 Western Standard Time and was in instrument meteorological conditions (IMC) during the climb.

The stick shaker stall warning system activated soon after the aircraft reached top of climb at Flight Level (FL) 340 and while the aircraft was accelerating to cruise speed. The flight crew did not receive any 'STALL' annunciation on their respective primary flight displays, nor any 'STALL STALL' aural warning or klaxon alert.

The flight crew initiated an immediate on-track descent and advised air traffic services of their requirement to change level. There was an infringement of the relevant procedural separation standards as the aircraft descended through the cruise level of an opposite direction aircraft.

An analysis of the flight recorder data indicated that the activation of the stick shaker was as a consequence of the angle-of-attack sensors becoming static during the climb. The investigation concluded that the immobilisation of the angle-of-attack sensors was consistent with ice restricting the movement of the 'slinger' on which the sensor vane is mounted.

The investigation assessed that the aircraft was not near a stalled condition of flight when the stick shaker warning activated. However, because the angle-of-attack sensors provided input to the aircraft's stall warning system, the immobilisation of those sensors adversely affected the reliability of the aircrafts stall warning system and could have render the automatic stall recovery system inoperative.

As a result of this incident, the aircraft and angle-of-attack sensor manufacturers initiated a detailed design review of the angle-of-attack sensor