Recently a series of three accelerated dynamic loading tests was carried out at the Canterbury Ac... more Recently a series of three accelerated dynamic loading tests was carried out at the Canterbury Accelerated Pavement Testing Indoor Facility (CAPTIF). The aim of these tests was to determine the influence of dynamic loading on pavement wear. This paper presents an investigation into the relationships between the permanent vertical surface deformation (VSD) of the pavement, the applied dynamic wheel loads and the pavement structural stiffness. It is shown that the VSD was correlated with both the pavement stiffness and the dynamic wheel forces but that the relationship with wheel forces was highly dependent on the level of dynamic loading. A surrogate measure for pavement strain formed by combining pavement stiffness and wheel force into a single parameter provided the strongest correlation with VSD. Using this "strain" parameter as the independent variable of a power law predictor for VSD gives a best fit estimate for the exponent between one and two.
Over time, the size and weight of heavy vehicles has gradually increased. As weight increases, pa... more Over time, the size and weight of heavy vehicles has gradually increased. As weight increases, pavement wear also increases. This is a concern for road controlling authorities who need to manage this and provide a serviceable network for their users. In New Zealand, the most widely used pavement construction is an unbound granular structure with chipseal surfacing. Asphaltic concrete is used on the more heavily trafficked sections of pavement, including parts of the State Highway network. With asphaltic concrete pavements, tensile shear stresses from tyres can cause surface cracking and ravelling. Thus, the increased use of non-steering axle groups is likely to result in increased pavement wear in the vicinity of intersections and roundabouts where tight low speed turns are executed. Recent research suggests that the damage to chipseal surfaces increases in proportion to the maximum tensile strain raised to the fifth power. In New Zealand, concern over these pavement damage effects ...
The road transport system is under immense pressure because of increased vehicles and traffic con... more The road transport system is under immense pressure because of increased vehicles and traffic congestion which leads to heavy wear and tear and high maintenance costs. Many studies shows that heavy vehicle loads resulted in pavement wear so it is better to use good suspensions which can reduce pavement wear.
International Journal of Heavy Vehicle Systems, 2014
It is well established that different heavy vehicle suspension systems generate different levels ... more It is well established that different heavy vehicle suspension systems generate different levels of dynamic loading on pavements, and it is generally accepted that higher dynamic loads cause more pavement wear. Thus some suspensions can be categorised as being more 'road–friendly' than others. Pavement maintenance is a substantial budget item for all road authorities and clearly there are benefits in encouraging the use of 'road–friendly' suspensions. However, in order to do this, it is necessary to establish a method for rating suspensions. This paper describes an experimental programme aimed at developing a cost–effective rating procedure for suspensions using a general–purpose two post servohydraulic shaker facility. The vehicle's on–road behaviour is monitored using relatively simple instrumentation, and this measured response is then reproduced in the laboratory using the shakers to excite the vehicle. Wheel forces are measured with instrumentation on the ac...
In recent years there has been considerable research interest in the effects of vehicle dynamics ... more In recent years there has been considerable research interest in the effects of vehicle dynamics on pavement wear, culminating in the US$1.5 million dollar OECD DIVINE research project which was completed in 1997. This is not surprising. The growth in road freight traffic has resulted in increased wear on the road network. Reducing this wear through reducing dynamic loads is an attractive proposition. The static component of vehicle loads is largely determined by the mass of freight to be transported.
Journal of the Australasian College of Road Safety
There is an increased risk of death or serious injury for occupants who did not wear a seat belt ... more There is an increased risk of death or serious injury for occupants who did not wear a seat belt in a crash. In New Zealand, between 2006 and 2016, the non-use of seat belts accounted for 19-30% of the overall motor vehicle road deaths, and this figure shows no sign of decreasing. It is important to better understand the contextual factors associated with crashes where seat belts are not worn, so that more relevant and effective road safety interventions can be designed and implemented. The aim of this research was to determine the profiles for seat belt non-users who were killed in motor vehicle crashes in New Zealand between 2011 and 2015. An in-depth analysis of 200 fatalities where seat belts were not worn (186 crash cases) was carried out following a Safe System framework, using NZ Police reports. Following this, a Multiple Correspondence Analysis (MCA) developed five profiles of vehicle occupants who were killed in crashes where seat belts were not worn. While the stereotypica...
Forestry is a major industry in New Zealand, which is set to grow significantly. Estimates indica... more Forestry is a major industry in New Zealand, which is set to grow significantly. Estimates indicate that the log harvest will double by 2010. As almost all of the growth is in new forestry areas, which are not well served by rail, the road log transport industry will grow by more than the growth in the harvest. On 1997 figures, the log transport fleet consisted of approximately 650
The relationships between the vehicle response to on-road excitations and laboratory based shaker... more The relationships between the vehicle response to on-road excitations and laboratory based shaker excitations are investigated by using simplified dynamic models. The technique would enable the excitations needed to simulate the on-road behavior to be generated without having first measured the on-road behavior. The adequacy of the approach is evaluated and discussed. Differences between suspension performance on the road and
A parliamentary inquiry into truck crashes (Anderson and Sinclair, 1996) initiated by the New Zea... more A parliamentary inquiry into truck crashes (Anderson and Sinclair, 1996) initiated by the New Zealand Government identified the poor stability of logging trucks as an area of particular concern. A subsequent analysis of crash statistics (Baas and Latto, 1997) showed that logging trucks were involved in a disproportionately high number of crashes and in particular rollovers. It was conservatively estimated
Heavy vehicle dimensions and mass regulations exist primarily to maintain safety and to preserve ... more Heavy vehicle dimensions and mass regulations exist primarily to maintain safety and to preserve the infrastructure. In terms of these aims, prescriptive regulations are a crude mechanism but they are straightforward to measure and thus compliance checking is relatively simple and cheap. Since the RTAC study, which led to the first of these symposia in 1987, there has been increasing
Recently a series of three accelerated dynamic loading tests was carried out at the Canterbury Ac... more Recently a series of three accelerated dynamic loading tests was carried out at the Canterbury Accelerated Pavement Testing Indoor Facility (CAPTIF). The aim of these tests was to determine the influence of dynamic loading on pavement wear. This paper presents an investigation into the relationships between the permanent vertical surface deformation (VSD) of the pavement, the applied dynamic wheel loads and the pavement structural stiffness. It is shown that the VSD was correlated with both the pavement stiffness and the dynamic wheel forces but that the relationship with wheel forces was highly dependent on the level of dynamic loading. A surrogate measure for pavement strain formed by combining pavement stiffness and wheel force into a single parameter provided the strongest correlation with VSD. Using this "strain" parameter as the independent variable of a power law predictor for VSD gives a best fit estimate for the exponent between one and two.
Over time, the size and weight of heavy vehicles has gradually increased. As weight increases, pa... more Over time, the size and weight of heavy vehicles has gradually increased. As weight increases, pavement wear also increases. This is a concern for road controlling authorities who need to manage this and provide a serviceable network for their users. In New Zealand, the most widely used pavement construction is an unbound granular structure with chipseal surfacing. Asphaltic concrete is used on the more heavily trafficked sections of pavement, including parts of the State Highway network. With asphaltic concrete pavements, tensile shear stresses from tyres can cause surface cracking and ravelling. Thus, the increased use of non-steering axle groups is likely to result in increased pavement wear in the vicinity of intersections and roundabouts where tight low speed turns are executed. Recent research suggests that the damage to chipseal surfaces increases in proportion to the maximum tensile strain raised to the fifth power. In New Zealand, concern over these pavement damage effects ...
The road transport system is under immense pressure because of increased vehicles and traffic con... more The road transport system is under immense pressure because of increased vehicles and traffic congestion which leads to heavy wear and tear and high maintenance costs. Many studies shows that heavy vehicle loads resulted in pavement wear so it is better to use good suspensions which can reduce pavement wear.
International Journal of Heavy Vehicle Systems, 2014
It is well established that different heavy vehicle suspension systems generate different levels ... more It is well established that different heavy vehicle suspension systems generate different levels of dynamic loading on pavements, and it is generally accepted that higher dynamic loads cause more pavement wear. Thus some suspensions can be categorised as being more 'road–friendly' than others. Pavement maintenance is a substantial budget item for all road authorities and clearly there are benefits in encouraging the use of 'road–friendly' suspensions. However, in order to do this, it is necessary to establish a method for rating suspensions. This paper describes an experimental programme aimed at developing a cost–effective rating procedure for suspensions using a general–purpose two post servohydraulic shaker facility. The vehicle's on–road behaviour is monitored using relatively simple instrumentation, and this measured response is then reproduced in the laboratory using the shakers to excite the vehicle. Wheel forces are measured with instrumentation on the ac...
In recent years there has been considerable research interest in the effects of vehicle dynamics ... more In recent years there has been considerable research interest in the effects of vehicle dynamics on pavement wear, culminating in the US$1.5 million dollar OECD DIVINE research project which was completed in 1997. This is not surprising. The growth in road freight traffic has resulted in increased wear on the road network. Reducing this wear through reducing dynamic loads is an attractive proposition. The static component of vehicle loads is largely determined by the mass of freight to be transported.
Journal of the Australasian College of Road Safety
There is an increased risk of death or serious injury for occupants who did not wear a seat belt ... more There is an increased risk of death or serious injury for occupants who did not wear a seat belt in a crash. In New Zealand, between 2006 and 2016, the non-use of seat belts accounted for 19-30% of the overall motor vehicle road deaths, and this figure shows no sign of decreasing. It is important to better understand the contextual factors associated with crashes where seat belts are not worn, so that more relevant and effective road safety interventions can be designed and implemented. The aim of this research was to determine the profiles for seat belt non-users who were killed in motor vehicle crashes in New Zealand between 2011 and 2015. An in-depth analysis of 200 fatalities where seat belts were not worn (186 crash cases) was carried out following a Safe System framework, using NZ Police reports. Following this, a Multiple Correspondence Analysis (MCA) developed five profiles of vehicle occupants who were killed in crashes where seat belts were not worn. While the stereotypica...
Forestry is a major industry in New Zealand, which is set to grow significantly. Estimates indica... more Forestry is a major industry in New Zealand, which is set to grow significantly. Estimates indicate that the log harvest will double by 2010. As almost all of the growth is in new forestry areas, which are not well served by rail, the road log transport industry will grow by more than the growth in the harvest. On 1997 figures, the log transport fleet consisted of approximately 650
The relationships between the vehicle response to on-road excitations and laboratory based shaker... more The relationships between the vehicle response to on-road excitations and laboratory based shaker excitations are investigated by using simplified dynamic models. The technique would enable the excitations needed to simulate the on-road behavior to be generated without having first measured the on-road behavior. The adequacy of the approach is evaluated and discussed. Differences between suspension performance on the road and
A parliamentary inquiry into truck crashes (Anderson and Sinclair, 1996) initiated by the New Zea... more A parliamentary inquiry into truck crashes (Anderson and Sinclair, 1996) initiated by the New Zealand Government identified the poor stability of logging trucks as an area of particular concern. A subsequent analysis of crash statistics (Baas and Latto, 1997) showed that logging trucks were involved in a disproportionately high number of crashes and in particular rollovers. It was conservatively estimated
Heavy vehicle dimensions and mass regulations exist primarily to maintain safety and to preserve ... more Heavy vehicle dimensions and mass regulations exist primarily to maintain safety and to preserve the infrastructure. In terms of these aims, prescriptive regulations are a crude mechanism but they are straightforward to measure and thus compliance checking is relatively simple and cheap. Since the RTAC study, which led to the first of these symposia in 1987, there has been increasing
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Papers by John de Pont