| 1. |
- Ihs, Anita
(författare)
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The influence of road surface condition on traffic safety
- 2005
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- During the latest years VTI has carried out research within a project called "The impact of road surface on traffic" on commission by the Swedish National Road Administration (SNRA). The objective of the project is to improve and supplement the road user effect models in the SNRA pavement management system (PMS). Studies have been/are being carried out on the impact of road surface on vehicle speed, ride comfort, fuel consumption, noise properties and safety. The main objective with this study has been to provide new models describing the relation between traffic safety and the road surface condition. In the accident cost model used today the only road surface parameter included is rut depth and only ruts deeper than 10 mm are considered to have any influence on traffic safety. The relation is then linear and the accident cost increases with increasing rut depth. The investigation that has been carried out is based on data from the road surface measurements done by SNRA on the state roads during the period 1992 - 1998 and accidents reported by the police during the same period. Also data on precipitation has been used. Regression analyses have mainly been used. Dependent Y-variable has been accident ratio (accidents/ 100 million axles pair kilometres). Independent X-variables have been rut depth (mm) and/or unevenness given in the measure of unevenness called International Roughness Index (IRI in mm/m). The material has been divided into several different classes such as traffic flow and precipitation classes.
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| 2. |
- Jacobson, Torbjörn, et al.
(författare)
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Prediction models for pavement wear and associated costs
- 2005
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Rapport (populärvet., debatt m.m.)abstract
- Prediction models that describe changes in the condition of various portions of a road structure constitute a valuable tool for evaluating the service life and economics of a road structure or of a surfacing measure. Prediction models also constitute the core of planning systems - Pavement Management Systems - which are based on changes in the condition of various road structures and asphalt layers depending on traffic and time. The prediction model discussed in this report describes the magnitude of wear of pavement and of rut formation created by vehicles with studded tyres. The objective was to develop a computer based prediction model for the rut formation that is caused by wear from studded tires. The model shall both provide a prediction of the wear resistance of the wearing course based on data regarding the type of wearing course, the properties of component materials, and a model of the rut profile based on data for type of road, traffic load, etc.
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| 3. |
- Möller, Staffan
(författare)
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Ersättningsmodell för vinterväghållning
- 2005
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Rapport (populärvet., debatt m.m.)abstract
- En bra ersättningsmodell för att, utifrån vinterns karaktär, reglerakostnader för vinterväghållning mellan beställare och utförare kräver två välfungerande delmodeller. - En delmodell som beskriver vädret undervintersäsongen. - En delmodell som kopplar väderbeskrivningar tillåtgärdsbehov/resursinsatser. Grunden för väderbeskrivningar är rådata frånenskilda stationer i Vägverkets system för vägväderinformation, VViS, ellerfrån s.k. MESAN-analyser från SMHI. VViS-stationerna genererar punktvärden,medan MESAN anger värden som medeltal över rutor som är 22 x 22 km stora.
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| 4. |
- Möller, Staffan, et al.
(författare)
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Tema Vintermodell
- 2005
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Rapport (populärvet., debatt m.m.)abstract
- Varje år drabbas trafikanterna av olägenheter på grund av is och snö på våravägar, gator och gång- och cykelbanor. Problemen är främst ökad olycksriskoch försämrad framkomlighet. För att förebygga eller i varje fall minskaproblemen, vidtar väghållarna driftåtgärder av olika slag, som till exempelsnöröjning och halkbekämpning. Åtgärderna är till nytta för trafikanterna,men innebär kostnader för väghållarna och negativa effekter för miljön. Detär därför angeläget att utveckla system för konsekvensbeskrivning av olikadriftstrategier och -metoder för att göra det möjligt att minimera desamhällsekonomiska kostnaderna. För investeringsplanering av vägar och gatorhar man sedan länge haft kalkylmodeller för beräkning av olika effekter:förutom kostnader för planerings- och byggnadsprocesserna även förändringarav trafikalstring, restider, olycksrisker och mycket annat. Drift- ochunderhållssidan är i detta avseende mycket eftersatt, och det är naturligtvisen svaghet, när det gäller att konkurrera om begränsade medel med ekonomiskaargument. Bristerna gäller inte minst vinterväghållningen
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| 5. |
- Offrell, Petra, et al.
(författare)
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Crack measures and reference systems for a harmonised crack data collection using automatic systems
- 2005
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The increased use of automatic systems for crack data collection has created some interesting questions about suitable crack measures. Traditional measures are sometimes unsuitable or even impossible to obtain using automatic data collection. However, the efficient and fast automatic crack data collection has also increased the numbers of possible measures that can be calculated from the results. Another issue originated from the need of conformance within Europe as well as globally is the necessity of an acceptable reference system that can be used to compare and accept different systems. This paper discusses different cracks measures and possible reference systems. The need for different measures, based on the level of which the application is intended to, is also discussed.
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| 6. |
- Sjögren, Leif, et al.
(författare)
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Design an up to date rut depth monitoring profilometer, requirements and limitations
- 2005
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Sweden has a long tradition in road surface condition monitoring. There are two measures that have dominated the estimation of the road surface condition; namely rut depth and IRI (International Roughness Index). Rut depth is the estimate of unevenness in the transverse and IRI in the longitudinal direction of the road. Deformation or wear that shows up as rut depth are common in Sweden. One big reason is that there is a law to use winter tyres (usually studded) during the winter season. Yet another reason is the actual loads that are transported. To detect differences in wear origin certain specifications is needed to be fulfilled in the design of the monitoring device. This report will deal with findings and conclusions made from years of experience in Sweden. The organized road surface monitoring scheme started in the end of 1970: s. The result is stored in the Swedish PMS (Pavement Management System). Almost all paved roads maintained by the government have been monitored every year. In this paper the result is focused on 10 years of data from one of the seven regions in Sweden. The length of measured roads in this region, Mälardalen is approximately 3000 km per year. A mean transverse profile is stored every 20 meter of measured road. Each profile is estimated from 17 sensors.
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| 7. |
- Öberg, Gudrun, et al.
(författare)
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Winter tyres : Traffic safety
- 2005
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Rapport (populärvet., debatt m.m.)abstract
- During the winter 1993/94, the Swedish National Road Administration received considerable criticism for its winter maintenance and in particular for the high consumption if road salt. This led to discussions on changing the rules for winter maintenance. Some ice or snow was temporary allowed on the roads with high winter maintenance standard. More roads were degraded to lower winter maintenance standard where ice or snow were permanently permitted. In addition, certain changes intended to influence driver behaviour and vehicle equipment for example mandating the use of winter tyres were to be studied. The purpose of the first investigation described in this paper was to calculate the socio-economic consequences that may be expected from a requirement on winter tyres in various circumstances. In the second investigation in this paper the traffic safety effect of the requirement is studied. A requirement of using winter tyres when it is slippery was selected based on facts from the first investigation.
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