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Rune Elvik - One of the best experts on this subject based on the ideXlab platform.

  • area wide urban Traffic Calming schemes a meta analysis of safety effects
    Accident Analysis & Prevention, 2001
    Co-Authors: Rune Elvik
    Abstract:

    This paper presents a meta-analysis of 33 studies that have evaluated the effects on road safety of area-wide urban Traffic Calming schemes. Area-wide urban Traffic Calming schemes are typically implemented in residential areas in towns in order to reduce the environmental and safety problems caused by road Traffic. A hierarchical road system is established and through Traffic is removed from residential streets by means of, for example, street closures or one-way systems. Speed reducing devices are often installed in residential streets. Main roads are improved in order to carry a larger Traffic volume without additional delays or more accidents. The meta-analysis shows that area-wide urban Traffic Calming schemes on the average reduce the number of injury accidents by about 15%. The largest reduction in the number of accidents is found for residential streets (about 25%), a somewhat smaller reduction is found for main roads (about 10%). Similar reductions are found in the number of property damage only accidents. The results of evaluation studies are robust with respect to study design. There is no evidence of publication bias in evaluation studies. Study findings are found to have high external validity.

  • area wide urban Traffic Calming schemes a meta analysis of safety effects
    Traffic Safety on Two ContinentsPTRC Education and Research Services Limited, 2000
    Co-Authors: Rune Elvik
    Abstract:

    This paper presents a meta-analysis of 33 studies that have evaluated the effects on road safety of area wide urban Traffic Calming schemes. Area wide urban Traffic Calming schemes are typically implemented in residential areas in towns in order to reduce the environmental and safety problems caused by road Traffic. A hierarchical road system is established and through Traffic is removed from residential street by means of, for example, street closures or one-way systems. Speed reducing devices are often installed in residential streets. Main roads are improved in order to carry a larger Traffic volume without additional delays or more accidents. The meta-analysis shows that area wide urban Traffic Calming schemes on the average reduce the number of injury accidents by about 15%. The largest reduction in the number of accidents is found for residential streets, a somewhat smaller reduction is found for main roads. The results of evaluation studies are robust with respect to study design. There is no evidence of publication bias in the evaluation studies. Study findings are found to have high external validity.

Marianne Hatzopoulou - One of the best experts on this subject based on the ideXlab platform.

  • simulating the environmental effects of isolated and area wide Traffic Calming schemes using Traffic simulation and microscopic emission modeling
    Transportation, 2014
    Co-Authors: Golnaz Ghafghazi, Marianne Hatzopoulou
    Abstract:

    This study focuses on the development of a microscopic Traffic simulation and emission modeling system which aims at quantifying the effects of different types of Traffic Calming measures on vehicle emissions both at a link-level and at a network-level. It also investigates the effects of isolated Traffic-Calming measures at a corridor level and area-wide Calming schemes, using a scenario analysis. Our study is set in Montreal, Canada where a Traffic simulation model for a dense urban neighborhood is extended with capabilities for microscopic emission estimation. The results indicate that on average, isolated Calming measures increase carbon dioxide (CO2), carbon monoxide (CO), and nitrogen oxides (NOx) emissions by 1.5, 0.3, and 1.5 %, respectively across the entire network. Area-wide schemes result in a percentage increase of 3.8 % for CO2, 1.2 % for CO, and 2.2 % for NOx across the entire network. Along specific corridors where Traffic Calming measures were simulated, increases in emissions of up to 83 % were observed. We also account for the effect of different measures on Traffic volumes and observe moderate decreases in areas that have undergone Traffic Calming. In spite of Traffic flow reductions, total emissions do increase.

  • simulating the environmental effects of isolated and area wide Traffic Calming schemes using Traffic simulation and microscopic emission modeling
    Transportation Research Board 92nd Annual MeetingTransportation Research Board, 2013
    Co-Authors: Golnaz Ghafghazi, Marianne Hatzopoulou
    Abstract:

    This study focuses on the development of a microscopic Traffic and emission simulation system which aims at quantifying the effects of different types of Traffic Calming measures on vehicle emissions both at a link-level and at a network-level. It also investigates the effects of isolated Traffic-Calming measures at a corridor level and area-wide Calming schemes, using a scenario analysis. The study is set in Montreal, Canada where a Traffic simulation model for a dense urban neighborhood is extended with capabilities for microscopic emission estimation. The results indicate that on average, isolated Calming measures increase carbon dioxide (CO2), carbon monoxide (CO), and nitrogen oxide (NOx) emissions by 1.50%, 0.33%, and 1.45%, respectively across the entire network. Area-wide schemes result in a percentage increase of 3.84% for CO2, 1.22% for CO, and 2.18% for NOx. Along specific corridors where Traffic Calming measures were simulated, increases in emissions of up to 83% were observed. These increases are mainly associated with a change in vehicle drive-cycles through increased accelerations and decelerations. The authors also account for the effect of different measures on Traffic volumes and observe moderate decreases in areas that have undergone Traffic Calming. In spite of Traffic flow reductions, total emissions do increase. Finally, they observe that speed bumps result in higher emission levels than speed humps.

Alfredo Garcia - One of the best experts on this subject based on the ideXlab platform.

  • use of speed profile as surrogate measure effect of Traffic Calming devices on crosstown road safety performance
    Accident Analysis & Prevention, 2013
    Co-Authors: Ana Tsui Moreno, Alfredo Garcia
    Abstract:

    Abstract Urban road safety management is usually characterized by the lack of sufficient, good quality crash data and low budgets to obtain it even though many Traffic accidents occur there. For example, 54 percent of road crashes in Spain take place in urban areas, and 10 percent of urban fatal crashes occur on crosstown roads, which are rural roads that traverse small communities. Traffic Calming measures (TCMs) are often implemented on these parts of rural roads that traverse small communities in order to reduce both the frequency and severity of crashes by lowering speeds, but evaluation of their effectiveness has been limited. The objective of this study was to develop a methodology using continuous speed profiles to evaluate the safety effectiveness of TCMs on crosstown roads as part of an integrated system in the absence of historical data. Given the strong relationship between speed and crash experience, safety performance can be related to speed. Consequently, speed can be used indirectly as a surrogate safety measure in the absence of crash and speed data. Two indexes were defined in this study as surrogate safety measures based on the continuous speed profile: Ra and Ea. Ra represents the absolute accumulated speed variations relative to the average speed and is inversely related to accumulated speed uniformity; and Ea represents the accumulated speed variations above the speed limit and is directly related to accumulated speeding. Naturalistic data were collected using GPS trackers for 12 scenarios with different TCM spacings. Then, the indexes were applied to individual observed speed profiles (individual analysis) as well as the operating speed profile (global analysis). The values obtained from individual and global analysis were statistically different. Spacing lower than 110 m, which was found optimal from previous research, did not allow drivers to modify their speeds as the accumulated speed uniformity was quite similar regardless of the average operating speed; and, accumulated speeding was also minimized. Consequently, the scenarios where the TCMs were implemented according to the technical criteria presented a better design quality. On the other hand, age and gender differences did not seem to affect the average speeds or the accumulated speed uniformity and accumulated speeding.

  • Traffic microsimulation study to evaluate the effect of type and spacing of Traffic Calming devices on capacity
    Procedia - Social and Behavioral Sciences, 2011
    Co-Authors: Alfredo Garcia, Antonio Jose Torres, Mario Romero, Ana Tsui Moreno
    Abstract:

    Traffic Calming is widely implemented to improve road safety. However, the implementation of Traffic Calming devices implies less capacity of cross-town roads. The present research used Traffic microsimulation to study the effect of Traffic Calming devices on the cross-town roads capacity based on different type and spacing of devices. Average delay was calculated. Then, capacity of the road was obtained for a fixed Traffic Calming device spacing as the flow rate from which delay presented exponential growth. Capacity of a cross-town road varied between 810 and 1300 vehicles per hour and lane with Traffic Calming devices spacing from 25 to 400 meters.

  • use of speed profile as surrogate measure effect of Traffic Calming devices on crosstown road safety performance
    3rd International Conference on Road Safety and SimulationPurdue UniversityTransportation Research Board, 2011
    Co-Authors: Ana Tsui Moreno, Alfredo Garcia
    Abstract:

    Urban road safety management is usually characterized by both a lack of quantity and quality of crash data and low budgets. However, fifty three percent of road crashes in Spain take place on crosstown roads and urban areas. Moreover, ten percent of fatal crashes on urban areas occur on crosstown roads. In order to reduce both crash frequency and severity, Traffic Calming measures (TCMs) are often implemented on crosstown roads. The objective of the research is to develop a methodology using continuous speed profile on free-flow conditions to evaluate safety effectiveness of Traffic Calming measures on crosstown roads. Given the strong relationship between speed and crash experience, safety performance can be related to speed. Consequently, speed can be used indirectly as a surrogate safety measure. Two indexes were defined as surrogate safety measures based on the continuous speed profile: Ra and Ea, related to speed uniformity and speeding, respectively. The indexes were applied to both individual observed speed profiles and aggregated operating speed profile. Twenty four global values of both indexes were obtained. The scenarios with implemented TCMs according to technical criteria, such as a Traffic Calming density close to nine TCMs per km, presented lower values. Age and gender differences have also been evaluated. More scenarios based on speed predictions over the TCMs will be modeled to propose Ra and Ea safety threshold values. The paper explores continuous speed profiles obtained from naturalistic driving to assess safety performance of crosstown roads with Traffic Calming devices. With this approach, speed is in effect used as a surrogate safety measure formulated in two new indexes: Ra and Ea.

Golnaz Ghafghazi - One of the best experts on this subject based on the ideXlab platform.

  • simulating the environmental effects of isolated and area wide Traffic Calming schemes using Traffic simulation and microscopic emission modeling
    Transportation, 2014
    Co-Authors: Golnaz Ghafghazi, Marianne Hatzopoulou
    Abstract:

    This study focuses on the development of a microscopic Traffic simulation and emission modeling system which aims at quantifying the effects of different types of Traffic Calming measures on vehicle emissions both at a link-level and at a network-level. It also investigates the effects of isolated Traffic-Calming measures at a corridor level and area-wide Calming schemes, using a scenario analysis. Our study is set in Montreal, Canada where a Traffic simulation model for a dense urban neighborhood is extended with capabilities for microscopic emission estimation. The results indicate that on average, isolated Calming measures increase carbon dioxide (CO2), carbon monoxide (CO), and nitrogen oxides (NOx) emissions by 1.5, 0.3, and 1.5 %, respectively across the entire network. Area-wide schemes result in a percentage increase of 3.8 % for CO2, 1.2 % for CO, and 2.2 % for NOx across the entire network. Along specific corridors where Traffic Calming measures were simulated, increases in emissions of up to 83 % were observed. We also account for the effect of different measures on Traffic volumes and observe moderate decreases in areas that have undergone Traffic Calming. In spite of Traffic flow reductions, total emissions do increase.

  • simulating the environmental effects of isolated and area wide Traffic Calming schemes using Traffic simulation and microscopic emission modeling
    Transportation Research Board 92nd Annual MeetingTransportation Research Board, 2013
    Co-Authors: Golnaz Ghafghazi, Marianne Hatzopoulou
    Abstract:

    This study focuses on the development of a microscopic Traffic and emission simulation system which aims at quantifying the effects of different types of Traffic Calming measures on vehicle emissions both at a link-level and at a network-level. It also investigates the effects of isolated Traffic-Calming measures at a corridor level and area-wide Calming schemes, using a scenario analysis. The study is set in Montreal, Canada where a Traffic simulation model for a dense urban neighborhood is extended with capabilities for microscopic emission estimation. The results indicate that on average, isolated Calming measures increase carbon dioxide (CO2), carbon monoxide (CO), and nitrogen oxide (NOx) emissions by 1.50%, 0.33%, and 1.45%, respectively across the entire network. Area-wide schemes result in a percentage increase of 3.84% for CO2, 1.22% for CO, and 2.18% for NOx. Along specific corridors where Traffic Calming measures were simulated, increases in emissions of up to 83% were observed. These increases are mainly associated with a change in vehicle drive-cycles through increased accelerations and decelerations. The authors also account for the effect of different measures on Traffic volumes and observe moderate decreases in areas that have undergone Traffic Calming. In spite of Traffic flow reductions, total emissions do increase. Finally, they observe that speed bumps result in higher emission levels than speed humps.

Kadar Hamsa, Abdul Azeez - One of the best experts on this subject based on the ideXlab platform.

  • Urban Traffic system, 2nd ed.
    IIUM Press International Islamic University Malaysia, 2020
    Co-Authors: Kadar Hamsa, Abdul Azeez
    Abstract:

    Urban Traffic System constitutes a group of interdependent and interrelated Traffic and related components which are intended to form a unified entity to accomplish smooth, orderly and safe movement of vehicles in an urban area. The number of trips being attracted to urban areas is normally very high due to the presence of high density commercial and business land uses. In the local context, these trips to the urban areas were usually performed by private vehicles and thus has increased the number of private vehicles entering into the urban areas on a daily basis. Due to limited road and other transport infrastructure in urban areas, the increasing number of private vehicles has caused continuing increase in the level of Traffic congestion, thereby decreasing the speed of the vehicles, increasing the travel and delay time, increasing the air pollution level and increasing the discomfort and inconveniences of the road users. It is very import to understand the effects of the increase in Traffic on road and other transport infrastructure. The first edition of this book covers topics on Traffic volume, speed, road intersection, road capacity, level of service, parking, Traffic control devices, road safety, and Traffic management measures including Traffic Calming. This second edition of the book on “Urban Traffic System” has made significant changes in its overall contents. As the main scope of this book focuses on road Traffic, a new chapter on “Road Network and Geometrics” narrating functions of road, classification of roads, road cross-sectional elements and road circulation system is added in this edition of the book. To facilitate the understanding on various topics that are being covered in this edition of the book by the readers, exercises in the form of quiz and other questions are added at the end of each chapter including the newly introduced chapter on road network and geometrics. This will help the readers especially students in the higher learning institutions to search for answers to these questions from this book which further strengthens the understanding of the various topics in this book. In the “speed studies” chapter, few images depicting the measurement of spot speed are improved. Additionally, a new section on how to convert ungrouped data into grouped data for the purpose of calculating speed characteristics is added in this chapter. In the “parking studies” chapter, new figures on parking layout and internal Traffic circulation in the parking layout are added to understand the circulation of Traffic in an off-street parking layout. A new section on “road capacity of different roads and Traffic lane conditions” providing data on road capacity for different types of roads and road geometrics is added in road capacity and level of service chapter. The analytical formula to calculate spacing and headway of vehicles is added together with the changes in the explanation of relationship between speed and density, volume and speed and volume and density and explanation on different level of service. In the “road intersection” chapter, some of the figures illustrating the layout of the intersections were improved. Traffic management measures and Traffic Calming chapter in the first edition of this book is split into two separate chapter in this edition, one describing on Traffic management measures and another on Traffic Calming with improvement on Traffic Calming chapter. The increasing number of vehicles in a city or a town has significantly attributed to frequent changes in the characteristics of Traffic components such as speed, volume, capacity, road design and safety. A study on these imminent changes would eventually provide explanations on the impediment in Traffic movement, which, in turn, helps to ameliorate safety of the road users. Better understanding of the Traffic components and characteristics would play an important role in designing effective and efficient road system for smooth, orderly and safe Traffic movement. It will also help to gain better and further insights on Traffic maneuverability by Traffic and transport professionals. Additionally, the present state of literature on Traffic components and characteristics is very much focused on overseas case studies and thus necessitates the need for undertaking a study on this subject in the local context. The findings on Traffic components based on case studies in the local context would help students in higher learning institutions and other related communities to better comprehend Traffic and transportation components. Automatic/electronic and other related equipments were used to measure Traffic and transport components such as Traffic volume, speed, road intersection and capacity, level of service, parking Traffic control devices, road safety, and Traffic management measures. To exemplify, radar gun was used to measure speed, Traffic volume counters to measure Traffic volume of mixed Traffic including at road intersections, and observational field survey to evaluate level of service, Traffic control devices, Traffic management and Traffic Calming measures. Analysis on each of the Traffic and transport component was performed by using appropriate analytical techniques. The findings from the analysis on each of these Traffic components are highlighted and discussed in this book. This book is expected to further strengthen the literature on each of the selected Traffic components, especially in the local context. It is also expected to benefits students, especially in higher learning institutions and professionals in the field of urban Traffic system, Traffic planning and engineering, to understand the methodology involved to collect and analyse Traffic data to arrive at important decisions on Traffic operations to achieve smooth, orderly and safe Traffic movements

  • Evaluating the effects of road hump on the speed of vehicles in an institutional environment
    Eastern Asia Society for Transportation Studies, 2019
    Co-Authors: Rosli, Nur Najiah Azhani, Kadar Hamsa, Abdul Azeez
    Abstract:

    Vehicles travelling at speed above the permissible speed limit have jeopardized the safety of road users. The concern is greater at institutional environment whereby most road users travel by walking. Road hump is considered as an efficient Traffic Calming measure in reducing the speed of the vehicle. This paper investigates the effects of different road hump dimensions in decreasing the speed of vehicles at the main road of International Islamic University Malaysia. Six (6) road humps with different design profile were selected. The design profile and spot speed of the vehicles at all six (6) road humps were measured. The speed of vehicles at the road hump was analyzed by using descriptive analysis and t-test. The findings of this study suggest that road hump is effective in lowering the speed of vehicles in an institutional environment. The dimensions of road hump, especially height, influence significantly the speed reduction of vehicles

  • Evaluating the effects of road hump as a Traffic Calming measure on speed and noise level at a university setting
    International Islamic University Malaysia, 2018
    Co-Authors: Mohamed, Mohd Zin, Kadar Hamsa, Abdul Azeez, Mustafa, Nur Asiah, Rosli, Nur Najiah Azhani
    Abstract:

    Traffic speed and noise are the major transport-related determinants in affecting the quality of learning and research environment in a University. The calm and safe environmental set-up of a University is very crucial in creating a conducive learning and research atmosphere on-campus. The increasing number of private vehicles on-campus has resulted in increase in speed and noise level and thus has attributing towards increase in environmental pollution on-campus. Road humps are considered effective as a Traffic Calming measure in reducing speed and thus noise level of the moving vehicles especially near and middle of the two road humps. However, the imminent reduction in speed of the vehicles depends very much on the profiles of a road hump in terms of its width, length and height. The difference in the profiles of the road hump will cause changing driving behavior of the users especially when approaching a road hump. The road humps with different design profiles are selected to measure the speed and noise level of the vehicles at, before and after each of the selected road humps. Radar speed gun and noise level meters are used to measure speed and noise level of the vehicles at each of designated points along the major circular road in IIUM. Descriptive and fluctuation trend analysis is applied to ascertain the changes in speed and noise level at each of the selected points along the major road in IIUM. The changes in speed and noise level at different selected points at each of the different design profiles of the road humps are the expected findings of this study. The findings stated that road hump profiles affect the speed and noise level of moving vehicle. From that, several recommendations also being highlighted in improving the effectiveness of road humps

  • A review of literature on the effects of road hump on Traffic speed and Traffic noise in institutional area
    2018
    Co-Authors: Mustafa, Nur Asiah, Kadar Hamsa, Abdul Azeez
    Abstract:

    Traffic speed and noise are the major transport-related determinants in affecting the quality of learning and research environment in a University. The calm and safe environmental set-up of a University is very crucial in creating a conducive learning and research atmosphere on-campus. The increasing number of private vehicles on-campus has resulted in the increase in speed and noise level and thus has attributing towards an increase in environmental pollution on-campus. Road humps are considered effective as a Traffic Calming measure in reducing speed and noise level of the moving vehicles. However, the imminent reduction in the speed of the vehicles depends very much on the profiles of a road hump in terms of its width, length and height. The difference in the profiles of the road hump will cause changing driving behavior of the users, especially when approaching a road hump. Thus, this paper is part of the ongoing study to analyse the effectiveness of road hump as a Traffic Calming measure in the campus area. The literature on Traffic Calming in Malaysia is highlighted in this paper