| 1. |
- Nilsson, Rickard, et al.
(författare)
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Utredning och provning av kostnadseffektiva metoder för bullerminimering av spårfordon
- 2013
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Ingår i: Transportforum 2013. - Linköping : Statens väg- och transportforskningsinstitut. ; , s. 122-135
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Konferensbidrag (refereegranskat)abstract
- Den här artikeln avser att för ett befintligt spårtrafiksystem översiktligt beskriva olika bullerreducerande åtgärders effekt, deras ekonomiska aspekter samt indirekt inverkan på systemet och dess omgivning. SL (AB Storstockholms Lokaltrafik) arbetar aktivt för att minska tågtrafikens störning till omgivningen, med den långsiktiga strävan att hela SLs spårsystem ska innehålla riktvärden för ny- och ombyggd järnväg enligt infrastrukturpropositionen. Ett viktigt medel för att nå denna ambition är succesivt byte av fordonsparken till nya och tystare fordon, detta kommer dock inte ge tillräcklig bullerreduktion, ytterligare åtgärder kommer att krävas. Beroende på problembilden kan det innebära att en enstaka åtgärd eller flera åtgärder i kombination behöver tas till. För att kartlägga, utvärdera och skapa kunskap om olika åtgärdsalternativ har SL därför arbetat långsiktigt och systematiskt med att utvärdera ett antal olika metoder. En viktig aspekt i sammanhanget är att då SLs spår till stor del går mycket nära bostäder är det önskvärt att hitta effektiva bullerskyddsåtgärder med så liten påverkan som möjligt avseende landskapsbild och barriäreffekt. Med hänsyn till ägardirektivet om ekonomi i balans är det även viktigt att se till total nytta relativt total kostnad vid val av åtgärd.
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| 2. |
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| 3. |
- Edwards, Henrik, et al.
(författare)
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Trafikarbetet uttryckt i fordonskilometer på väg i Sverige 1950-1997
- 2000
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- SIKA har, efter en konkurrensupphandling, gett VTI i uppdrag att, utifrån tillgänglig information, redovisa antalet motorfordonskilometer somårligen uträttats på väg fördelat efter vägtyp, fordonstyp och drivmedel för åren 1950–1997, samt redovisa en beräkningsmodell somkan an-vändas för motsvarande framtida skattningar av trafikarbetet och dess fördelning. Många har varit direkt eller indirekt inblandade i projektet. En ingång till projektet har varit den katalogisering somJörgen Larsson, VTI, gjort av Vägverkets samlade kunskap från trafikräkningar och skattningar av trafikarbete på det statliga vägnätet. En ovärderlig källa är, och har varit, den årliga publikationen ”Bilismen i Sverige”, samtGun-Britt Ljungdahls bearbetning av vägmätaruppgifter vid Svensk Bilprovning. Dessa har utgjort röda trådar genomprojektet. Författarna tackar dem och övrig personal vid VTI och SCB som varit berörda, samt SIKA:s referensgrupp och den projektansvarige vid SIKA, Lennart Thörn.
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| 4. |
- Eriksson, Olle, 1967-, et al.
(författare)
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Statistical analysis of curve squeal based on long-term onboard noise measurements
- 2022
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Curve squeal with large magnitude tonal components in the frequency range up to 10 kHz is a cause of annoyance without any satisfying solution. This might be partly due to the gaps in the current understanding of the phenomenon within the research community (e.g. the open question whether the fundamental excitation mechanism is due to “falling friction” or “modal coupling”). Rail-bound traffic is expected to become a backbone in the future sustainable public transportation system. This makes it urgent to increase the state of knowledge in order to develop effective mitigation measures against the problem.Noise recorded by an onboard monitoring system during one year of traffic on the Stockholm metro is studied. The influence of selected variables on the generation of curve squeal is investigated in a statistical assessment. The influence of curve radius on curve squeal probability is estimated by calculating the quotient of squealing samples with respect to the total number of samples captured in circular curve sections. Vehicle speed (operative conditions) is modelled by the introduction of a classification representing different speed profiles (e.g. constant, linear acceleration or deacceleration, etc.). Environmental conditions are accounted for by using humidity and air temperature as predictor variables.A general trend of increased probability of curve squeal for decreasing curve radius is observed. Several subsequent regression analyses could not find a consistent influence of air temperature and humidity on the occurrence of curve squeal. Moreover, preliminary results indicate the existence of a vehicle speed for which a curve is particularly prone to generate squeal noise.
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| 5. |
- Eriksson, Olle, 1967-, et al.
(författare)
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Survey of Curve Squeal Occurrence for an Entire Metro System
- 2024
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Ingår i: Noise and Vibration Mitigation for Rail Transportation Systems. - : Springer. - 9789819978519 - 9789819978526 ; , s. 483-490
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Bokkapitel (refereegranskat)abstract
- The current work presents a statistical analysis based on data collected during approximately 1.5 years of regular operation by two vehicles equipped with an on-board noise monitoring system on the Stockholm metro. Data covers 379,776 passages through 143 curves with radii up to 1000 m. Binary logistic regression is used to investigate the importance of curve radius, vehicle speed, relative humidity, air temperature, rail grinding and vehicle individual on curve squeal. Curve squeal occurrence shows an inverse proportionality with respect to curve radius. This trend is particularly pronounced for curve radii below 600 m. The two vehicles accounted for in the study show differences in propensity to generate squeal. The influence of temperature and relative humidity, and their interaction, on curve squeal is described by an estimated response surface. Results show the occurrence of curve squeal to increase after rail grinding. No strong relationship between curve squeal occurrence and vehicle speed is identified.
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| 6. |
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| 7. |
- Nilsson, Peter, et al.
(författare)
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High speed control of long combination heavy commercial vehicles within safe corridors
- 2016
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The main scope of the project was to initiate a technical framework for studying manual and automated high-speed driving of long vehicle combinations (LVCs) in a driving simulator environment.The project included implementation and evaluation of vehicle models representing a rigid truck solo (reference vehicle) and an A-double LVC in VTI driving simulator IV (Sim IV). The A-double combination consisted of a 6x4 tractor unit followed by a three-axle semi-trailer, two-axle converter dolly and a second three-axle semi-trailer unit. The total vehicle length of the A-double was 32 metres and the total weight was set to 80 tonnes. The implementation of the vehicle models was evaluated by drivers from Volvo product development. The evaluation was carried out during normal driving conditions, with speeds ranging from 0 to 90 km/h.Besides the implementation and evaluation of vehicle models, the project also included a driving simulator study in which manual and automated driving of the A-double have been studied. The participants in the study were 12 professional truck drivers from a haulage contractor and 8 drivers from Volvo product development. The driving scenario consisted of a relatively curvy and hilly single-lane Swedish county road (Road 180), without additional road users and safety critical events. Two automated driving strategies for steering, propulsion and braking were formulated, whereof one of the steering strategies included results from an optimal control based receding horizon approach. The drivers’ manual lane keeping and speed profiles were recorded for post-analysis. In addition, the drivers’ subjective acceptance of automated driving trajectories was also collected.
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| 8. |
- Nilsson, Peter, 1976, et al.
(författare)
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On actions of long combination vehicle drivers prior to lane changes in dense highway traffic : A driving simulator study
- 2018
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Ingår i: Transportation Research Part F. - : Elsevier. - 1369-8478 .- 1873-5517. ; 55, s. 25-37
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Tidskriftsartikel (refereegranskat)abstract
- In this paper we address drivers’ actions prior to mandatory lane changes of long combination vehicles in dense highway traffic. The studied driver actions were: turn indicator activation, speed reduction and lateral intrusion. We categorised and compared the drivers’ actions with respect to the surrounding traffic cooperation and the level of urgency. Urgency here was based on the remaining distance to a targeted exit ramp. The results show that when the subject vehicle is close to the exit ramp, drivers used speed reduction significantly more than when the vehicle is further away. No significant difference was found for the use of lateral intrusion considering the distance to the exit ramp. As regards traffic cooperation, significant differences were found for both speed reduction and lateral intrusion. The drivers’ speed reduction and lateral intrusion were significantly greater when the surrounding traffic cooperation was low.
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| 9. |
- Sandin, Jesper, 1975-, et al.
(författare)
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A Lane-Change Gap Acceptance Scenario Developed for Heavy Vehicle Active Safety Assessment : A Driving Simulator Study
- 2015
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Ingår i: Proceedings of the 3rd International Symposium on Future Active Safety Technology Towards zero traffic accidents, 2015. ; , s. 537-543
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Konferensbidrag (refereegranskat)abstract
- The aims of this study were to develop a lane-change scenario for driving simulators in order to analyse the characteristics of lane-change manoeuvres performed with heavy vehicles. The scenario was set up based on information from lane-change accidents and on-road lane-change observations. The gap acceptance scenario consisted of two consecutive lane changes were the intention was to study truck drivers’ accepted gap between two vehicles in the adjacent right lane, at the initiation of each lane change. An experiment was conducted with 18 truck drivers in a full-motion driving simulator with implemented high fidelity models of an 80tonnes and 32m long vehicle combination and a 40tonnes and 22m tractor semi-trailer. The results showed no statistically significant difference in the accepted gaps to the lead and lag vehicles in the target lane. For both heavy vehicles, the overall average lead gap and lag gap was estimated to 0.85s and 0.83s respectively, at the average velocity of 17.3m/s. The difference in lane-change duration for the two vehicles was statistically significant and estimated to an average of 8.7s for the tractor semi-trailer, and 10.5s for the A-double. The conclusion from the present study is that the drivers performed the lane changes equally well with the tractor semi-trailer and the long vehicle combination. There were no major differences between the manoeuvres other than the duration times, which can be justified by the difference in vehicle length. Future studies are able to use this scenario as a non-critical reference to more critical events in the development and assessment of active safety functionality and automated driving systems.
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| 10. |
- Sandin, Jesper, 1975-, et al.
(författare)
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A lane-change scenario developed for assessment of active safety and ADAS in heavy vehicles : evaluated in a driving simulator study
- 2017
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The aim of this project was to develop a lane-change scenario for driving simulators to analyse the characteristics of lane-change manoeuvres performed with heavy vehicles.The definition of the lane-change scenario was based on a literature review, and an investigation of lane-change accidents in Sweden.A lane-change manoeuvre is in the literature typically described by accepted gap at the initiation of the manoeuvre as well as duration of the manoeuvre and speed during the manoeuvre. The literature review showed that there is a lack of real-world data regarding lane-change manoeuvres with heavy vehicles. The data that exist are collected mainly in the US and for discretionary lane changes, and a distinction between sizes of heavy vehicles is rarely made. Regarding accidents involving heavy vehicles on European level, there is a general lack of useful and reliable accident data. The most comprehensive data are available from the US and show that lane-change accidents account for a large share of accidents involving heavy vehicles.The investigation of lane-change accidents was made in the Swedish Traffic Accident Data Acquisition (STRADA), on 10 500 police-reported accidents with heavy vehicles involved during the years 2003 to 2013. In STRADA, lane-change accidents are categorized together with overtaking accidents. Therefore, it is not possible to identify lane-change accidents and their share of heavyvehicle accidents directly from STRADA. Instead, lane-change accidents were identified by reading the accident narratives for overtaking accident and rear-end accidents (in total 5 612 accidents). Rearend accidents were included because the manner of collision may resemble lane-change collisions.
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