Analysis and design optimisation have been carried out to find the best suitable design of the collapsible sign post which can minimize the possibility of injuring the passenger in the car during crash impact. The post also needs to be strong enough to withstand the wind load and self-weight. Many different design configurations were analysed and parametrical study was carried out. A couple of designs have been identified to be better in terms of minimizing the acceleration of the car during crash impact. This report discusses the modelling aspects of the finite element analysis and presents the results.
Monday, December 29, 2008
Monday, December 22, 2008
Regulatory approach to fatigue in car drivers and Current driving hours regulations
Current driving hours regulations do not meet evidence based critical factors
The expert group's evidence-based critical factors are similar to those identified by expert panels in the United States and Canada and when applied to assess the current prescriptive driving hours regime highlight deficiencies including:
The expert group's evidence-based critical factors are similar to those identified by expert panels in the United States and Canada and when applied to assess the current prescriptive driving hours regime highlight deficiencies including:
- The maximum working (including driving) period in a day does not accommodate circadian patterns (time of day factors);
- The minimum rest periods do not account for cumulative fatigue issues and the variable length of break required for adequate sleep opportunity at different times of the day;
- The minimum rest periods do not accommodate the opportunity for night sleep;
- The short rest breaks are arbitrary and do not allow breaks to be taken when they may be of most benefit.
The expert group's recommendations present challenges for industry and regulators
The expert group's primary focus was on the scientific basis for any regulatory options but it was cognizant of operational, social and economic cost-benefit and compliance dimensions. It gave consideration to a range of factors like journey completion issues, queuing and slotting, availability of rest stations, cost burdens and ease of enforcement.
It was recognised that some of the proposals may create challenges for current operational practices but the expert group was equally clear that improvement and reduced risk is dependent on some of those practices changing to accommodate the state of knowledge about fatigue. The need for change is not limited to the driving task but must encompass the supply chain.
These design principles should be considered in developing prescriptive traditional driving hours regulation or other options such as performance based regulations and codes of practice. To illustrate how the design principles could be applied, an indicative model was prepared by the expert group. The expert group saw this as one way of progressing the better management of fatigue but anticipated there would be other ways of putting the principles into practice.
Whilst the process of developing regulatory options involves robust examination of many factors and inevitable pragmatic compromises, the design principles set out in this report are considered fundamental to improved outcomes.
The expert group's primary focus was on the scientific basis for any regulatory options but it was cognizant of operational, social and economic cost-benefit and compliance dimensions. It gave consideration to a range of factors like journey completion issues, queuing and slotting, availability of rest stations, cost burdens and ease of enforcement.
It was recognised that some of the proposals may create challenges for current operational practices but the expert group was equally clear that improvement and reduced risk is dependent on some of those practices changing to accommodate the state of knowledge about fatigue. The need for change is not limited to the driving task but must encompass the supply chain.
These design principles should be considered in developing prescriptive traditional driving hours regulation or other options such as performance based regulations and codes of practice. To illustrate how the design principles could be applied, an indicative model was prepared by the expert group. The expert group saw this as one way of progressing the better management of fatigue but anticipated there would be other ways of putting the principles into practice.
Whilst the process of developing regulatory options involves robust examination of many factors and inevitable pragmatic compromises, the design principles set out in this report are considered fundamental to improved outcomes.
Tuesday, December 16, 2008
Drink Driving Mental health and social support
All offenders reported experiencing a high level of mental health and social support at the time of the initial interview, as measured by the Mental Health Inventory, the Social Support Appraisals Scale and the Interpersonal Support Evaluation List. No difference was found between the UTL and Control groups on these measures.
Number of prior drink driving convictions was found to influence the level of support received from friends and others, and also the level of self-esteem support received. Offenders with prior drink driving convictions reported lower levels of social support in all instances.
The UTL program did not increase the level of mental health and social support experienced by offenders, relative to the amount of change seen in the Control group over the course of the study.
Knowledge
At the time of the first interview, offenders in the UTL group showed more accurate knowledge for alcohol and drink driving-related issues. However, over the 9 months between interviews, the knowledge of offenders in the UTL group did not improve to any greater extent compared to the knowledge of offenders in the Control group.
Number of prior drink driving convictions was found to influence the level of support received from friends and others, and also the level of self-esteem support received. Offenders with prior drink driving convictions reported lower levels of social support in all instances.
The UTL program did not increase the level of mental health and social support experienced by offenders, relative to the amount of change seen in the Control group over the course of the study.
Knowledge
At the time of the first interview, offenders in the UTL group showed more accurate knowledge for alcohol and drink driving-related issues. However, over the 9 months between interviews, the knowledge of offenders in the UTL group did not improve to any greater extent compared to the knowledge of offenders in the Control group.
Monday, December 8, 2008
Travelling Speed and Risk of Crash Involvement Conclusions
In rural out of town areas, the risk of involvement in a casualty crash increases greater than exponentially with increasing free travel speed. Even travelling just 10 km/h faster than the average speed of other traffic was found to double the risk of crash involvement.
It was also found that small reductions in travelling speed in rural areas have the potential to greatly reduce casualty crashes in those areas; that illegal speeding is responsible for a significant proportion of rural crashes; and that reducing the maximum speed limit on undivided roads to 80 km/h could be expected to have a marked effect on casualty crash frequency.
We therefore recommend that:
1. The level of enforcement of speed limits in rural areas be increased.
2. The tolerance allowed in the enforcement of rural speed limits be reduced or eliminated.
3. All currently zoned 110 km/h undivided roads be rezoned to no more than 100 km/h.
4. Speed limits be reduced where current limits are considerably greater than average travelling speeds and where there are frequently occurring Advisory Speed signs.
5. After a period with stricter enforcement of rural area speed limits, consideration be given to changing the maximum speed limit to 80 km/h on all two lane rural roads, as is the practice on two lane rural roads in many States in the USA.
6. The level of public awareness of the risk of involvement in a casualty crash associated with speeding be increased with the aim of developing a culture of compliance with speed limits, and support for strict limits, similar to that which has developed in relation to compliance with blood alcohol limits during recent decades.
7. To assist with the preceding recommendation, we also recommend that the results of this study be widely publicised.
It was also found that small reductions in travelling speed in rural areas have the potential to greatly reduce casualty crashes in those areas; that illegal speeding is responsible for a significant proportion of rural crashes; and that reducing the maximum speed limit on undivided roads to 80 km/h could be expected to have a marked effect on casualty crash frequency.
We therefore recommend that:
1. The level of enforcement of speed limits in rural areas be increased.
2. The tolerance allowed in the enforcement of rural speed limits be reduced or eliminated.
3. All currently zoned 110 km/h undivided roads be rezoned to no more than 100 km/h.
4. Speed limits be reduced where current limits are considerably greater than average travelling speeds and where there are frequently occurring Advisory Speed signs.
5. After a period with stricter enforcement of rural area speed limits, consideration be given to changing the maximum speed limit to 80 km/h on all two lane rural roads, as is the practice on two lane rural roads in many States in the USA.
6. The level of public awareness of the risk of involvement in a casualty crash associated with speeding be increased with the aim of developing a culture of compliance with speed limits, and support for strict limits, similar to that which has developed in relation to compliance with blood alcohol limits during recent decades.
7. To assist with the preceding recommendation, we also recommend that the results of this study be widely publicised.
Tuesday, December 2, 2008
Society Attitudes to Road Safety Demographic Comparisons
The research clearly shows that age is the main predictor of how frequently drivers exceed the speed limit. However, while the tendency to exceed the speed limit continues to decline with age, the number of under 24 year olds saying they mostly or always do so has declined from 20% to 15% and is now at the same level as the 25-39 years age group.
Speed tends still to be referred to far more often than drink driving as the single main cause of road crashes, regardless of age. The one exception is those under 24 who mention speed and drink driving with similar frequency. Mentions of speed as one of three main crash factors has declined, reflecting a greater focus on the dangers of drink driving among this group.
However, more 15-24 year olds are now showing support for strict adherence to the limit in a 60 km/h zone, and while similar numbers support 65 km/h, the number tolerating 70 km/h in a 60 km/h zone has halved. Traditionally, tolerance of speeds in excess of 60 km/h could be seen to decline with age. In this survey speed tolerance is broadly similar across the 15-60 year group, then drops markedly, with 60% of those over 60 years favouring strict enforcement. A similar pattern emerges in relation to speed tolerance in 100 km/h zones.
While approval for RBT remains high across the age groups, over one in ten males aged 15-24 years disagree with it. This youngest age group continues to be the most inclined to feel that RBT levels have increased. Claimed exposure to RBT is highest among this age group, which is also the most inclined to say a BAC of .05 will affect their ability as a pedestrian. This youngest age group is most likely to say I dont drink if driving (48% compared with a national average of 37%), and remains the most interested in the use of self-operated breath testing machines. Some 22% of the 15-24 years age group (up from 14% in CAS 13) have used such a device in the past six months.
CAS 14 has shown an increasing awareness of fatigue as a key crash factor, among people under 40 years, from 36% in CAS 13 to 43%, against a national average of 33%.
Speed tends still to be referred to far more often than drink driving as the single main cause of road crashes, regardless of age. The one exception is those under 24 who mention speed and drink driving with similar frequency. Mentions of speed as one of three main crash factors has declined, reflecting a greater focus on the dangers of drink driving among this group.
However, more 15-24 year olds are now showing support for strict adherence to the limit in a 60 km/h zone, and while similar numbers support 65 km/h, the number tolerating 70 km/h in a 60 km/h zone has halved. Traditionally, tolerance of speeds in excess of 60 km/h could be seen to decline with age. In this survey speed tolerance is broadly similar across the 15-60 year group, then drops markedly, with 60% of those over 60 years favouring strict enforcement. A similar pattern emerges in relation to speed tolerance in 100 km/h zones.
While approval for RBT remains high across the age groups, over one in ten males aged 15-24 years disagree with it. This youngest age group continues to be the most inclined to feel that RBT levels have increased. Claimed exposure to RBT is highest among this age group, which is also the most inclined to say a BAC of .05 will affect their ability as a pedestrian. This youngest age group is most likely to say I dont drink if driving (48% compared with a national average of 37%), and remains the most interested in the use of self-operated breath testing machines. Some 22% of the 15-24 years age group (up from 14% in CAS 13) have used such a device in the past six months.
CAS 14 has shown an increasing awareness of fatigue as a key crash factor, among people under 40 years, from 36% in CAS 13 to 43%, against a national average of 33%.
Subscribe to:
Posts (Atom)