| 51. |
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| 52. |
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| 53. |
- Hydén, Christer, et al.
(författare)
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The effects on safety, time consumption and environment of large scale use of roundabouts in an urban area
- 2000
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Ingår i: Accident Analysis and Prevention. - 1879-2057. ; 32, s. 11-23
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Tidskriftsartikel (refereegranskat)abstract
- An experiment with small roundabouts – as speed reducing measures - was carried out in a Swedish city. The purpose of the study was to test the large scale and long term effects of the roundabouts. The results showed that the roundabouts reduced the speed considerably at the junctions and on links between roundabouts. The lateral displacement the roundabout forces the driver to has a great importance for the speed of approaching cars to a roundabout. The speed-reducing effect is large already at a 2 meter’s deflection. A larger deflection does not result in a larger effect. Conflict studies indicated an overall decrease in accident risk by 44%. Vulnerable road-users’ risk was reduced significantly, while there was no reduction for car occupants. There is a relation between the reduction of approach speed and the reduction of injury accident risk. The time consumption at a time operated signal was reduced heavily by the instalment of a roundabout at a signalised intersection. On average, emissions (CO and NOx) at roundabouts replacing non-signalised junctions increased by between 4 and 6%, while a roundabout replacing a signalised intersection led to a reduction by between 20 and 29%. The noise level was reduced at junctions that were provided with roundabout. Car drivers were less positive to the roundabouts than bicyclists. In the long term, the unchanged roundabouts worked almost as good as they did shortly after the rebuilding. The study showed that details in the design are of decisive importance for road-users’ safety. Special attention has to be paid to the situation of bicyclists. The transition between the cycle path/lane and the junction has to be designed with care - the bicyclists should be integrated with motorised traffic before they enter the roundabout. There should be only one car lane both on the approach, in the circulating area and on the exit. The size of the roundabout shall be as small as possible.
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| 54. |
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| 55. |
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| 56. |
- Jansen, Sven, et al.
(författare)
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Validation Results
- 2008
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This report describes the validation of the SASPENCE driver support system using an evaluation method which has been developed within the scope of the SAfe SPEed and safe distaNCE (SASPENCE) project. SASPENCE aims to develop a driver support system that focuses on keeping a safe speed and safe heading distance in relation to other road users and road infrastructure. The system warns the driver to adapt to the situation and consequently the driver actions are influencing the effectiveness of SASPENCE. The Human Machine Interface design has therefore been a key aspect in the development of the system. The developed evaluation method is capable of dealing with a large variation of circumstances (including driver behaviour) and in all steps of the evaluation (apart from straightforward hardware tests) the driver is considered. The evaluation method consists of simulation-based functional tests, on-road functional tests, on-road subjective tests, and traffic impact assessment using simulation. The simulation-based functional tests (using a driver model) have been undertaken in three stages using a probabilistic method to cope with the large variation of circumstances. In the first stage a large number of Monte Carlo simulations were performed to assess the effectiveness of the basic SASPENCE algorithm, and to identify the most critical situations. In the second stage, Software-in-the-Loop simulations have been used to reduce the number of critical situations in order to arrive at a practical number of Hardware-in-the-Loop (HIL) experiments. The HIL experiments confirmed the effectiveness of the results of Monte Carlo simulations, and they additionally provided estimates for dependability parameters (i.e. Safety, Reliability, Appropriateness and Timeliness). On-road functional tests addressed conditions that can not be realised in HIL experiments; however, Appropriateness and Timeliness could not be determined. On-road subjective tests have been carried out in Spain and Italy by selecting 20 drivers at each location and letting each driver run a 50 km course with and without the SASPENCE system activated. Both experimental vehicles were equipped with systems for monitoring the driving session, recording camera images and vehicle motion data. Moreover, the Wiener Fahrprobe in-car observation method was used for the analysis of driver behaviour during the tests. From the users’ point of view, the system has been positively rated as being useful and well accepted by drivers, to an extent that the majority would be willing to pay up to 500 Euro to have it installed in their own vehicle. Also, from the experts’ point of view, the system was rated positively as for instance the number of conflicts and the number of events related to individual behavioural aspects decreased. The recorded vehicle data also confirmed the effectiveness of the system to reduce speed and increase heading distance. The Traffic impact assessment simulations show that the impact of SASPENCE is most apparent for high congestion levels where the positive (safety) effect is an increasing Time-to-Collision. However, the large reduction in the mean speed adversely affects traffic throughput.
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| 57. |
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| 58. |
- Kallberg, Veli-Pekka, et al.
(författare)
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MASTER – Managing Speeds of Traffic on European Rods. Final Report.
- 1999
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The content of the European research project MAnaging Speeds of Traffic on European Roads (MASTER) is presented. Speed management is described as a two-step process where target speeds for different kinds of roads are determined first, and then various measures and tools are applied in order to adopt such speed. Current practice and main problems in speed management are described. The various impacts of speed and the factors affecting drivers’ choice of speed as well as the various speed management measures and tools are discussed. Basic principles of rational speed management are outlined on these grounds. Finally, recommendations for further development of speed management and research needs are formulated. It is recommended that target speeds on different kinds of roads are determined on the basis of systematic and comprehensive assessment of all impacts of speed. The recommendations concerning speed management measures and tools include, for example, harmonisation of speed limits in different European countries, development of European guidelines for urban speed management, further development and wider use of automated speed enforcement, and introduction of adaptive in-vehicle speed limiters. Further research is needed on the impacts of speed on accidents, pollution and costs to road users as well as on the monetary valuation of these impacts. Standardisation of procedures used in collection and reporting of speed data is needed to facilitate international comparisons.
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| 59. |
- Kallberg, Veli-Pekka, et al.
(författare)
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Recommendations for Speed Management on European Roads
- 1999
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Ingår i: Transportation Research Board Annual Proceeding.
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Tidskriftsartikel (refereegranskat)abstract
- Results of a recent European research project MAnaging Speeds of Traffic on European Roads (MASTER) are presented. Speed management is described as a two-step process where target speeds for different kinds of roads are determined first, and then various measures and tools are applied in order to adopt such speed. Current practice and main problems in speed management are described. The various impacts of speed and the factors affecting drivers’ choice of speed as well as the various speed management measures and tools are discussed. Basic principles of rational speed management are outlined on these grounds. Finally, recommendations for further development of speed management and research needs are formulated. It is recommended that target speeds on different kinds of roads are determined on the basis of systematic and comprehensive assessment of all impacts of speed. The recommendations concerning speed management measures and tools include, for example, harmonisation of speed limits in different European countries, development of European guidelines for urban speed management, further development and wider use of automated speed enforcement, and introduction of adaptive in-vehicle speed limiters. Further research is needed on the impacts of speed on accidents, pollution and costs to road users as well as on the monetary valuation of these impacts. Standardisation of procedures used in collection and reporting of speed data is needed to facilitate international comparisons.
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| 60. |
- Kallberg, Veli-Pekka, et al.
(författare)
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Recommendations for Speed Management Strategies and Policies.
- 1998
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The aim of the project MASTER (MAnaging Speeds of Traffic on European Roads) was to produce information that can be cited in the preparation of national and EU decisions concerning speed management and speed control equipment standards. For this purpose, the project looked for answers to three key questions: 1)What are acceptable ranges of speeds? 2)What are the key factors influencing drivers’ choice of speed? 3)What are the best speed management tools and strategies? The results of the project are documented in 26 reports: 12 deliverables and 14 working papers. The objective of the this report is to present recommendations for speed management strategies and policies. Recommendations for Speed Management Measures, Tools and Policy 1.Speed limits on roads of similar classification in different European countries should be harmonised so that road users’ expectations are consistent with respect to correct choice of speed irrespective of previous driving experiences in their home country. These speed limits should reflect the socially desirable speeds determined for example with the help of the MASTER framework. 2.European guidelines are needed for application of speed management measures and tools on residential and main roads in urban areas and on rural mixed-traffic roads. This would promote consistent and cost-effective speed management both on urban roads, where a wider range of potential alternatives is available and on rural roads where the possibilities for using low-cost physical measures are more limited. 3.Preparations for the introduction of compulsory adaptive speed limiters should be started. Adaptive speed limiters automatically prevent speeding by adjusting speeds according to the prevailing speed limit. The first step could be large scale field experiments in urban areas in different countries. Urban roads are the best choice for the first application because on such roads their public acceptability is highest and potential negative effects e.g. in the form of behavioural adaptation are smallest. 4.Redesign of European roads according to the principles of self-explaining roads should include hierarchical categorisation into a limited number of categories so that each level has a distinct set of characteristics that is clearly different from that of other levels. A reduced and simplified road hierarchy would promote the correct choice of speed for each road type and have other positive effects on road safety by assisting correct anticipation of behaviour of other road users. 5.Automated speed enforcement should be developed further and taken into wider use. In some countries legislative changes are needed so that the owner of the vehicle can be held responsible for speeding offences. In addition, a common standard could be developed for identification of vehicles by an electronic device. Speeding vehicles are currently identified from photographs which often requires laborious manual work. Electronic identification devices could be used also for collection of parking fees and road tolls. Furthermore, equipment that is currently used only for traffic monitoring could be used for enforcement purposes (e.g. induction loops and data transfer equipment). 6.The difference between the effects of speed on social costs and on private costs should be reduced, for example by internalising external costs (e.g. accident costs and environmental costs). This would encourage drivers to choose speeds that are preferable not only from their private standpoint but also from society’s point of view. 7.Information and publicity campaigns regarding the impacts of speed are needed, with the purpose of giving neutral and objective information about all impacts of speed, with due attention to the difference between private and social costs. Such information could increase the public acceptance of speed restrictions that are justified from society’s viewpoint, but decision-makers will still need to recognise that popularity is not necessarily a good criterion for speed management policies. 8.The highest possible speed of vehicles should be limited to the highest speed limit on motorways and speed limits on motorways should be harmonised across Europe.
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