9 A possible cause of aircraft overruns or veer-offs on wet runways is hydroplaning. It is import... more 9 A possible cause of aircraft overruns or veer-offs on wet runways is hydroplaning. It is important 10 for airport operators to know the level of hydroplaning risk involved for different aircrafts 11 operating on the runways under their charge and to plan for appropriate actions to improve the 12 performance of their runways against hydroplaning occurrences. Current procedures of 13 hydroplaning speed estimation are unable to evaluate hydroplaning risks, primarily because they 14 are empirical and deterministic in nature.
Wet runways are known to be a major contributing factor in overrun accidents. Studies have shown ... more Wet runways are known to be a major contributing factor in overrun accidents. Studies have shown that low skid resistance caused by reduced friction on wet pavement leads to a longer braking distance and increases aircraft overrun risk. The common approaches to compute aircraft braking distance and overrun risk are based on either statistical predictive equations derived from accident data or analytical methods using estimated ground friction values.
Grooving of pavement surface and tire tread has been accepted as good practice to enhance road tr... more Grooving of pavement surface and tire tread has been accepted as good practice to enhance road travel safety against wet weather skidding and hydroplaning. Many guidelines on this practice have been derived from findings of experimental studies and field experience. However, theoretical studies to provide insights into the factors and mechanisms involved are lacking.
Hydroplaning is a unique phenomenon in which the water on a wet runway or highway is not displace... more Hydroplaning is a unique phenomenon in which the water on a wet runway or highway is not displaced from the nominal tire-ground contact area by a rolling tire or by a moving but nonrotating (full-skidding) tire at a rate fast enough to allow the tire to make contact with the ground surface over its complete nominal footprint area, as would the case of operation on a dry surface. When hydroplaning occurs, the tire rides on a wedge or film of water over a part or all of its footprint area, depending on the conditions.
ABSTRACT Pavement grooving has been used on highways as means to reduce hydroplaning and wetweath... more ABSTRACT Pavement grooving has been used on highways as means to reduce hydroplaning and wetweather accident occurrences. The need for pavement grooving arises because a plane pavement surface with little macrotexture generally has low hydroplaning speed and low frictional resistance at the onset of hydroplaning. This paper describes the use of a three-dimensional finite-volume hydroplaning simulation model to determine the hydroplaning speed associated with a particular groove design.
Abstract: There has been much concern on the need for integrated transportation planning and urba... more Abstract: There has been much concern on the need for integrated transportation planning and urban land use development to promote sustainablilty in metropolitan areas. An integrated transportation-land development framework is critical to explicitly address concerns on sustainability in urban areas. This paper shall examine the various options that can be used by transportation and urban development agencies to promote sustainability.
Abstract: Porous asphalt pavement is one solution to increased surface runoff due to urbanization... more Abstract: Porous asphalt pavement is one solution to increased surface runoff due to urbanization by allowing temporary storm-water retention. This paper aims to establish a rational basis for material selection, drainage design and rutting resistance evaluation of a porous asphalt pavement of this purpose.
Prepared in cooperation with the Indiana Department of Transportation and Federal Highway Adminis... more Prepared in cooperation with the Indiana Department of Transportation and Federal Highway Administration.
State highway agencies are facing immense pressure to maintain roads at acceptable levels amidst ... more State highway agencies are facing immense pressure to maintain roads at acceptable levels amidst the challenging financial and economic situations. In recent years, pavement preservation has been sought as a potential alternative for managing the pavement assets, believing that it could provide a cost-effective solution in maintaining infrastructural conditions and meeting user expectations.
Longitudinal pavement grooving has been applied in highways to reduce the occurrence of hydroplan... more Longitudinal pavement grooving has been applied in highways to reduce the occurrence of hydroplaning at accident-prone locations. However, to date there has not been a systematic study of its effectiveness against hydroplaning. This lack can be attributed to the difficulty in conducting such experiments and the extreme complexity of the theoretical analysis involved. A numerical model was developed to simulate the hydroplaning phenomenon. Then a systematic study was conducted on the effectiveness of various designs of longitudinal grooving against hydroplaning. The analysis covers groove widths of 2 to 10 mm, groove depths of 1 to 10 mm, and groove center-to-center spacing of 5 to 25 mm. Groove dimensions were found to have significant effects on the effectiveness of a grooving design against hydroplaning. The results show quantitatively how the use of larger groove width and depth and smaller groove spacing reduces hydroplaning risk, by computation of the changes in the expected hydroplaning speed. For the range of groove dimensions studied, the expected hydroplaning speed for a typical passenger car increased by approximately 2.8 km/h for every mm increase of groove depth, by approximately 3.5 km/h for every mm increase of groove width, and by approximately 1.0 km/h for every mm decrease of groove spacing. The model also was applied to evaluate the hydroplaning potential of different grooving designs used in practice and past studies and to explain the conflicting findings of past studies on whether longitudinal pavement grooving does improve traction and reduce hydroplaning risk.
Highway agencies commonly use automated pavement data collection techniques to collect pavement s... more Highway agencies commonly use automated pavement data collection techniques to collect pavement surface distress data at the network level. Although an immense amount of data is collected at the network level, agencies realize that there is a lack of understanding of the quality of the data collected. Traditionally, either the overall pavement condition rating or individual distress ratings are used to evaluate the quality of the condition data. However, each measure has its own pros and cons, rendering the use of a single measure ...
Journal of Transportation Safety & Security, Jan 1, 2012
This paper uses aggregate data from the World Health Organization (WHO) and the International Roa... more This paper uses aggregate data from the World Health Organization (WHO) and the International Road Federation (IRF) to identify the relationship between aggregate levels of road traffic safety, health service levels, motorization level, and associated factors. Two alternative modeling specifications are used to estimate the national fatality rate, number of hospital beds, and the number of registered vehicles per capita. The first specification is a system of seemingly unrelated regression equations (SURE) while the second is a set of regression models. The results suggest that a number of socio-economic explanatory factors, government laws and policies and their enforcement levels, and traffic and geographic characteristics, are significantly related to the three response variables. The paper shows that the SURE model is statistically superior to the separately-estimated regression models. The model findings are exploratory, but can still offer preliminary insights to planners to identify the extent to which traffic and motorization levels, regional and geographic characteristics, and most importantly, existing traffic laws and policies can influence traffic fatalities.
Transportation Planning and Technology, Jan 1, 2012
Malaysia is one of the few countries in the world that provides a fuel subsidy to consumers. Due ... more Malaysia is one of the few countries in the world that provides a fuel subsidy to consumers. Due to the recent economic crisis, the Malaysian Government decided to revise its fuel subsidization policy from a fixed price subsidy to a floating price subsidy dependent on global oil demand. Recognizing that the change in fuel subsidization policy can have an impact on travel behavior, this article investigates the short-term impact of the policy change on private and public transportation in the Klang Valley region of Malaysia. Spectral analyses are performed to investigate if the policy change has an impact on private vehicle travel demand, measured in terms of road traffic, and short-term travel demand elasticity with respect to fuel price is estimated. To measure the impact on the public transportation system, the demand cross-elasticity values of rail transit and buses are also estimated. It was found that traffic flow reduces with an increase in fuel price, although elasticity and cross-elasticity values obtained are low. The article finds that there is a potential mode shift from private vehicles to rail transit with increasing fuel price. It is demonstrated that reducing fuel price subsidy can be an effective travel demand management strategy to alleviate congestion.
Hydroplaning on wet pavement occurs when a vehicle reaches a critical speed and causes a loss of ... more Hydroplaning on wet pavement occurs when a vehicle reaches a critical speed and causes a loss of contact between its tires and the pavement surface. This paper presents the development of a three-dimensional finite volume model that simulates the hydroplaning phenomenon. The theoretical considerations of the flow simulation model are described. The simulation results are in good agreement with the experimental results in the literature and with those obtained by the well-known hydroplaning equation of the National ...
An important aspect of airport runway geometric design is ensuring prompt removal of water from t... more An important aspect of airport runway geometric design is ensuring prompt removal of water from the runway to reduce skidding and hydroplaning risks of aircraft operating under wet-weather conditions. However, current airport geometric design methods do not explicitly consider hydroplaning risk, and the adequacy of runway geometric design and the associated drainage system against hydroplaning has not been evaluated. In recognition of the need for a design procedure to ensure safe aircraft operations, a framework for runway ...
Journal of Transportation Engineering-asce, Jan 1, 2010
One aspect of commercial truck safety on highways is the risk of skidding. Skidding accidents inv... more One aspect of commercial truck safety on highways is the risk of skidding. Skidding accidents involving commercial trucks risk injury or death not only to their own occupants but also to other motorists and road users. Past research on truck skidding has been largely limited to empirical accident data analyses or experiments. Few analytical or numerical studies on the mechanisms of truck skidding on highways have been performed. This paper describes the development of a numerical simulation model that can evaluate the skid ...
Hydroplaning is known to be a major cause of wet-weather road accidents. The risk of hydroplaning... more Hydroplaning is known to be a major cause of wet-weather road accidents. The risk of hydroplaning in wet-weather driving is a function of the depth of surface water, pavement texture properties, and tire characteristics. With the aim to improve and ensure wet-weather driving safety, extensive experimental studies have been conducted by researchers to understand how tire characteristics (in particular, tire tread depth), would affect vehicle hydroplaning risk. Rib tires have been commonly used for such experiments. ...
9 A possible cause of aircraft overruns or veer-offs on wet runways is hydroplaning. It is import... more 9 A possible cause of aircraft overruns or veer-offs on wet runways is hydroplaning. It is important 10 for airport operators to know the level of hydroplaning risk involved for different aircrafts 11 operating on the runways under their charge and to plan for appropriate actions to improve the 12 performance of their runways against hydroplaning occurrences. Current procedures of 13 hydroplaning speed estimation are unable to evaluate hydroplaning risks, primarily because they 14 are empirical and deterministic in nature.
Wet runways are known to be a major contributing factor in overrun accidents. Studies have shown ... more Wet runways are known to be a major contributing factor in overrun accidents. Studies have shown that low skid resistance caused by reduced friction on wet pavement leads to a longer braking distance and increases aircraft overrun risk. The common approaches to compute aircraft braking distance and overrun risk are based on either statistical predictive equations derived from accident data or analytical methods using estimated ground friction values.
Grooving of pavement surface and tire tread has been accepted as good practice to enhance road tr... more Grooving of pavement surface and tire tread has been accepted as good practice to enhance road travel safety against wet weather skidding and hydroplaning. Many guidelines on this practice have been derived from findings of experimental studies and field experience. However, theoretical studies to provide insights into the factors and mechanisms involved are lacking.
Hydroplaning is a unique phenomenon in which the water on a wet runway or highway is not displace... more Hydroplaning is a unique phenomenon in which the water on a wet runway or highway is not displaced from the nominal tire-ground contact area by a rolling tire or by a moving but nonrotating (full-skidding) tire at a rate fast enough to allow the tire to make contact with the ground surface over its complete nominal footprint area, as would the case of operation on a dry surface. When hydroplaning occurs, the tire rides on a wedge or film of water over a part or all of its footprint area, depending on the conditions.
ABSTRACT Pavement grooving has been used on highways as means to reduce hydroplaning and wetweath... more ABSTRACT Pavement grooving has been used on highways as means to reduce hydroplaning and wetweather accident occurrences. The need for pavement grooving arises because a plane pavement surface with little macrotexture generally has low hydroplaning speed and low frictional resistance at the onset of hydroplaning. This paper describes the use of a three-dimensional finite-volume hydroplaning simulation model to determine the hydroplaning speed associated with a particular groove design.
Abstract: There has been much concern on the need for integrated transportation planning and urba... more Abstract: There has been much concern on the need for integrated transportation planning and urban land use development to promote sustainablilty in metropolitan areas. An integrated transportation-land development framework is critical to explicitly address concerns on sustainability in urban areas. This paper shall examine the various options that can be used by transportation and urban development agencies to promote sustainability.
Abstract: Porous asphalt pavement is one solution to increased surface runoff due to urbanization... more Abstract: Porous asphalt pavement is one solution to increased surface runoff due to urbanization by allowing temporary storm-water retention. This paper aims to establish a rational basis for material selection, drainage design and rutting resistance evaluation of a porous asphalt pavement of this purpose.
Prepared in cooperation with the Indiana Department of Transportation and Federal Highway Adminis... more Prepared in cooperation with the Indiana Department of Transportation and Federal Highway Administration.
State highway agencies are facing immense pressure to maintain roads at acceptable levels amidst ... more State highway agencies are facing immense pressure to maintain roads at acceptable levels amidst the challenging financial and economic situations. In recent years, pavement preservation has been sought as a potential alternative for managing the pavement assets, believing that it could provide a cost-effective solution in maintaining infrastructural conditions and meeting user expectations.
Longitudinal pavement grooving has been applied in highways to reduce the occurrence of hydroplan... more Longitudinal pavement grooving has been applied in highways to reduce the occurrence of hydroplaning at accident-prone locations. However, to date there has not been a systematic study of its effectiveness against hydroplaning. This lack can be attributed to the difficulty in conducting such experiments and the extreme complexity of the theoretical analysis involved. A numerical model was developed to simulate the hydroplaning phenomenon. Then a systematic study was conducted on the effectiveness of various designs of longitudinal grooving against hydroplaning. The analysis covers groove widths of 2 to 10 mm, groove depths of 1 to 10 mm, and groove center-to-center spacing of 5 to 25 mm. Groove dimensions were found to have significant effects on the effectiveness of a grooving design against hydroplaning. The results show quantitatively how the use of larger groove width and depth and smaller groove spacing reduces hydroplaning risk, by computation of the changes in the expected hydroplaning speed. For the range of groove dimensions studied, the expected hydroplaning speed for a typical passenger car increased by approximately 2.8 km/h for every mm increase of groove depth, by approximately 3.5 km/h for every mm increase of groove width, and by approximately 1.0 km/h for every mm decrease of groove spacing. The model also was applied to evaluate the hydroplaning potential of different grooving designs used in practice and past studies and to explain the conflicting findings of past studies on whether longitudinal pavement grooving does improve traction and reduce hydroplaning risk.
Highway agencies commonly use automated pavement data collection techniques to collect pavement s... more Highway agencies commonly use automated pavement data collection techniques to collect pavement surface distress data at the network level. Although an immense amount of data is collected at the network level, agencies realize that there is a lack of understanding of the quality of the data collected. Traditionally, either the overall pavement condition rating or individual distress ratings are used to evaluate the quality of the condition data. However, each measure has its own pros and cons, rendering the use of a single measure ...
Journal of Transportation Safety & Security, Jan 1, 2012
This paper uses aggregate data from the World Health Organization (WHO) and the International Roa... more This paper uses aggregate data from the World Health Organization (WHO) and the International Road Federation (IRF) to identify the relationship between aggregate levels of road traffic safety, health service levels, motorization level, and associated factors. Two alternative modeling specifications are used to estimate the national fatality rate, number of hospital beds, and the number of registered vehicles per capita. The first specification is a system of seemingly unrelated regression equations (SURE) while the second is a set of regression models. The results suggest that a number of socio-economic explanatory factors, government laws and policies and their enforcement levels, and traffic and geographic characteristics, are significantly related to the three response variables. The paper shows that the SURE model is statistically superior to the separately-estimated regression models. The model findings are exploratory, but can still offer preliminary insights to planners to identify the extent to which traffic and motorization levels, regional and geographic characteristics, and most importantly, existing traffic laws and policies can influence traffic fatalities.
Transportation Planning and Technology, Jan 1, 2012
Malaysia is one of the few countries in the world that provides a fuel subsidy to consumers. Due ... more Malaysia is one of the few countries in the world that provides a fuel subsidy to consumers. Due to the recent economic crisis, the Malaysian Government decided to revise its fuel subsidization policy from a fixed price subsidy to a floating price subsidy dependent on global oil demand. Recognizing that the change in fuel subsidization policy can have an impact on travel behavior, this article investigates the short-term impact of the policy change on private and public transportation in the Klang Valley region of Malaysia. Spectral analyses are performed to investigate if the policy change has an impact on private vehicle travel demand, measured in terms of road traffic, and short-term travel demand elasticity with respect to fuel price is estimated. To measure the impact on the public transportation system, the demand cross-elasticity values of rail transit and buses are also estimated. It was found that traffic flow reduces with an increase in fuel price, although elasticity and cross-elasticity values obtained are low. The article finds that there is a potential mode shift from private vehicles to rail transit with increasing fuel price. It is demonstrated that reducing fuel price subsidy can be an effective travel demand management strategy to alleviate congestion.
Hydroplaning on wet pavement occurs when a vehicle reaches a critical speed and causes a loss of ... more Hydroplaning on wet pavement occurs when a vehicle reaches a critical speed and causes a loss of contact between its tires and the pavement surface. This paper presents the development of a three-dimensional finite volume model that simulates the hydroplaning phenomenon. The theoretical considerations of the flow simulation model are described. The simulation results are in good agreement with the experimental results in the literature and with those obtained by the well-known hydroplaning equation of the National ...
An important aspect of airport runway geometric design is ensuring prompt removal of water from t... more An important aspect of airport runway geometric design is ensuring prompt removal of water from the runway to reduce skidding and hydroplaning risks of aircraft operating under wet-weather conditions. However, current airport geometric design methods do not explicitly consider hydroplaning risk, and the adequacy of runway geometric design and the associated drainage system against hydroplaning has not been evaluated. In recognition of the need for a design procedure to ensure safe aircraft operations, a framework for runway ...
Journal of Transportation Engineering-asce, Jan 1, 2010
One aspect of commercial truck safety on highways is the risk of skidding. Skidding accidents inv... more One aspect of commercial truck safety on highways is the risk of skidding. Skidding accidents involving commercial trucks risk injury or death not only to their own occupants but also to other motorists and road users. Past research on truck skidding has been largely limited to empirical accident data analyses or experiments. Few analytical or numerical studies on the mechanisms of truck skidding on highways have been performed. This paper describes the development of a numerical simulation model that can evaluate the skid ...
Hydroplaning is known to be a major cause of wet-weather road accidents. The risk of hydroplaning... more Hydroplaning is known to be a major cause of wet-weather road accidents. The risk of hydroplaning in wet-weather driving is a function of the depth of surface water, pavement texture properties, and tire characteristics. With the aim to improve and ensure wet-weather driving safety, extensive experimental studies have been conducted by researchers to understand how tire characteristics (in particular, tire tread depth), would affect vehicle hydroplaning risk. Rib tires have been commonly used for such experiments. ...
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