| 1. |
- Abdallah, Clement Kamil, et al.
(författare)
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Assessing the quality of water used for vegetable irrigation in Tamale Metropolis, Ghana
- 2021
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- This paper assesses water quality that is used for vegetable irrigation in Tamale Metropolis, Ghana. A mixed-method of research design was employed in this study to collect and analyze the data based on survey instruments. The paper found that Escherichia coli (E. coli) that is usually used as an indicator of water contamination and heavy metals exist in all taken water samples. The mean concentrations of nutrients such as ammonia, nitrate, nitrite and phosphate were recorded as 0.022 mg/l to 5.98 mg/l for ammonia, 1.06 mg/l to 7.52 mg/l for nitrate, 0.031 mg/l to 0.056 mg/l for nitrate and 0.037 mg/l to 0.069 mg/l for phosphate. E. coli and Total Coliforms levels for Sanghani, Kamina and Waterworks from the laboratory analysis were recorded as 3.2x10(3) CFU 100 m/l and 5.5x10(2) CFU 100 m/l, 4.0x10(3) CFU 100 m/l and 1x10(2) CFU 100 m/l, and 2.1x10(3) CFU 100 m/l and 4.6x10(2) CFU 100 m/l respectively. To conclude, based on the measured parameters, water used for irrigation in the Tamale Metropolitan is polluted and may cause potential health risks. Therefore, farmers, traders and consumers need to apply further safety measures to make the vegetables safe.
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| 2. |
- Abed, Ahmed, et al.
(författare)
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Uncertainty analysis of life cycle assessment of asphalt surfacings
- 2024
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Ingår i: International Journal on Road Materials and Pavement Design. - : Taylor & Francis. - 1468-0629 .- 2164-7402. ; 25:2, s. 219-238
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Tidskriftsartikel (refereegranskat)abstract
- The Life Cycle Assessment (LCA) of asphalt pavements are associated with significant uncertainty resulting from variability in the quantity and impact of individual components, the quality of data for each component, and variability of asphalt durability. This study presents a framework to quantify and incorporate the uncertainty of LCA and asphalt durability data into LCA of asphalt surfacings. The suggested framework includes: estimating the uncertainty of asphalt production processes by the pedigree matrix method, conducting a deterministic LCA, applying Monte Carlo Simulation (MCS) to estimate the probability density functions (PDFs) of the considered impacts using the uncertainty data, deterministic solution, and asphalt durability. This framework was applied to six asphalt mixtures; the results show that there is significant uncertainty in the processes that contribute to the environmental impacts. They also showed that considering asphalt durability and its uncertainty is critical and can significantly change the results and interpretation of LCA.
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| 3. |
- Adell, Emeli, et al.
(författare)
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Exponering av oskyddade trafikanter med hjälp av app-baserade resvaneundersökningar
- 2024
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Ingår i: Sammanställning av referat från Transportforum 2024. - Linköping : Statens väg- och transportforskningsinstitut. ; , s. 287-288
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Trafiksäkerhetsarbetet har kommit långt i Sverige, men det finns stora utmaningar kvar vad gäller oskyddade trafikanters trafiksäkerhetssituation. Trafiksäkerhetsrisken baseras på antalet olyckor eller personskador per trafikant, trafikarbete eller annat exponeringsmått. För oskyddade trafikanter är dock förståelsen av exponering begränsad och det finns generellt ett behov av bättre förståelse för oskyddade trafikanters exponering i termer av reslängder, tid i olika trafikmiljöer.Samtidigt som kunskapsläget kring skyddade trafikanters exponering i allmänhet är låg ger ökad digitalisering nya sätt att förstå människors resvanor och användning av trafiksystemet. I app-baserade resvaneundersökningar används positioneringsdata från mobiltelefonen, vilket kan ge värdefull information om exponering men också annan trafiksäkerhetsrelevant information, så som hastigheter.Denna studie har undersökt om data från app-baserade resvaneundersökningar kan använts för att ge värdefull information om a) den oskyddade trafikantgruppen, b) exponering och c) annan trafiksäkerhetsrelevant information. Underlaget har varit en kommunal app-baserad resvaneundersökning. Fokus har varit cyklister. Positioneringsdata har knutits till infrastrukturen via map-matching mot en geografisk databas. Genom detta kan typ av infrastruktur (till exempel gång- och cykelvägnät) och infrastrukturens olika egenskaper (till exempel hastighetsgränser) knytas till varje enskild del av en resa. Hastigheter har beräknats hjälp av GPS-positionering och tidsangivelser utmed hela resans sträckning. Vi har i denna studie valt att beräkna hastigheter på 50-meterssektioner, vilket bedöms ge en bra bild över hastighetsprofilen över resan.Det är med hjälp av data från app-baserad resvaneundersökning möjligt att beskriva hur mycket olika typer av individer cyklar, både i antal resor, reslängd och restid, både totalt och fördelat över dygnet. Den geografiska informationen gör det dessutom möjligt att förstå i vilken trafikmiljö som resor sker. I denna studie har vi analyserat hur mycket av transportarbetet som skett på olika typer av infrastruktur, vilket kan ställas i relation till var olyckor och skador skett för att beräkna trafiksäkerhetsrisker på olika typer av infrastruktur. I detta fall har vägtyp och hastighetsgräns använts, men det skulle också kunna vara typ av korsning om den data finns tillgänglig i den digitala beskrivningen av infrastrukturen.
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| 4. |
- Adell, Emeli, et al.
(författare)
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Investigating untapped bike potential with crowdsourcing data
- 2024
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Ingår i: Sammanställning av referat från Transportforum 2024. - Linköping : Statens väg- och transportforskningsinstitut. ; , s. 488-489
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The city of Lund has a high share of trips done by bicycle, and ambitious goals of becoming climate-neutral by 2030. Still the municipality, like many other cities, has difficulty in reaching the goals of increasing cycling and needs to find the real potential. To understand the untapped cycling potentials of a city, and generally to promote it, it is important to first assess how bike is used and why. This can be done by observing the bike flows and understanding the reasons for the use or misuse of bikes as a transport mode. Particularly, for the scope of identifying untapped potential, the preferred time scale should be smaller than the traditional count based on annual average figures. Also, opposite to motorized traffic, bicycle volume can rapidly change inside a city. All this caused the need to search for more effective methods to estimate bicycle volume like crowdsourcing data that can be provided by mobile apps which are usually collected for other purposes. The present study introduces a method of bicycle volume estimation based on GPS data from the TravelVu application, an app-based tool to collect travel survey data. A spatial analysis has been chosen to investigate the correlation between the data from the Lund municipality counting and the GPS data from TravelVu app. The analysis has been performed by comparing the average daily bike volume with the aggregated data in 3 months for the GPS track. Counting data refers to 2018 and 2021 and the TravelVu data refers to 3 months starting from August 2018 and 2021, where 2018 data are collected through crowdsourcing and 2021 are random sampling. All the weekend data have been removed since the manual counting was always carried out during weekdays (and should be represented by those). At first, all the data from the Lund municipality report were digitalized in a GIS map and then clustered per intersection to have a more robust regression when compared to the TravelVu data and to reduce the possible spatial errors.
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| 5. |
- Adesiyun, Adewole, et al.
(författare)
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Overview of connected and automated driving test sites
- 2020
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Ingår i: Proceedings of 8th Transport Research Arena TRA 2020. ; , s. 7-
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Konferensbidrag (refereegranskat)abstract
- Connected and automated vehicles potentially offer solutions to some key challenges for National Road Administrations (NRAs), such as reduction of accidents, increasing network capacity etc. As a result of this potential, both industry and certain national governments are undertaking trials that are mainly focused on technological challenges such as the ability of vehicles to drive safely in “random” situations etc. Far less attention has been paid to questions around the implications for NRAs. The overall aim of the STAPLE project is to provide a comprehensive review of technological and non-technological aspects of the most relevant connected and automated driving test sites in order to understand the impact of these sites on the NRAs’ core business and functions.
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| 6. |
- Afridi, Amjad, et al.
(författare)
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Management of municipal street network in Sweden : results from a national survey
- 2024
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Ingår i: Sammanställning av referat från Transportforum 2024. - Linköping : Statens väg- och transportforskningsinstitut. ; , s. 395-396
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Management of street networks is different from state roads due to its multifunctional role in society. This requires timely maintenance of the street network to improve socioeconomic development. Municipalities in Sweden are responsible for the management of about 42000 km of street network in their jurisdiction. Maintenance budget and resources vary from municipality to municipality depending on their network size, geographical location, and population density. A questionnaire was sent to all 290 municipalities across the country to investigate the street network and pavement management practices at the municipal level. An in-depth interview of 14 municipalities took place afterwards. A total of 51% of responses were officially received to highlight the frequently and infrequently occurring pavement distresses and their causes. Furthermore, the study highlights the maintenance approaches and allocation of budget to manage the street network. Lastly, the study highlights the factors which need to be addressed to improve street network management. Visual assessment of pavements is common and the use of pavement management system (PMS) is not only limited but also lacks pavement performance prediction models. Common pavement distresses are excessive formation of potholes, surface unevenness and alligator distress among the municipalities. Frequent causes of distress include the ageing of the street network, heavy vehicles, patching and high traffic flow. Furthermore, cold climate and population density are important factors in the degradation process. Allocation of maintenance and reconstruction budget is relatively high in municipalities located in the north. Densely populated municipalities have higher taxpayers’ contributions to maintenance and reconstruction. Other major issues are limited resources and maintenance of budget, which adversely affect the maintenance backlog and the choice of maintenance alternatives, ultimately the decision-making. This restricts the use of preventive maintenance among the municipalities. Municipalities are required to improve the frequency and quality of pavement data collection, enhance the sophistication of PMS by using pavement deterioration models, and increase the maintenance budget and resources. An insight into the capabilities of municipalities would help in long-term strategic planning and effective utilisation of the maintenance budget to improve the street network across the country.
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| 7. |
- Afridi, Muhammad Amjad, et al.
(författare)
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Municipal street maintenance challenges and management practices in Sweden
- 2023
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Ingår i: Frontiers in Built Environment. - : Frontiers Media S.A.. - 2297-3362. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- The municipal street network acts as a multifunctional asset by providing people, vehicles and public services with a well-functioning infrastructure. To keep it in good condition, optimal maintenance measures are required which would result in an efficient use of taxpayers' money. This paper investigates the street network deterioration processes and the management practices that the municipal administrations have applied in Sweden. The study is based on a survey with Swedish municipalities using questionnaires and complementary interviews. The answers provide insight into a wide range of common pavement distresses and deterioration factors, along with pavement management practices. The study identifies that potholes, surface unevenness and alligator cracking are the most cited challenges, while pavement ageing, heavy traffic and patches are the most noted causes. Similarly, the cold climate and population density are influential factors in pavement deterioration. Allocation of the maintenance and rehabilitation and reconstruction budget is higher in the northern part of the country as well as in densely populated municipalities. Condition data collection and use of commercial Pavement Management Systems (PMS) are limited. Addressing the challenges effectively may be possible through the enhancement of the budget, feasible/clear guidelines from municipal councils/politicians, and reducing the gap between street network administrations and utility service providers.
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| 8. |
- Ahlström, Christer, 1977-, et al.
(författare)
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Alcohol impairs driver attention and prevents compensatory strategies
- 2023
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Ingår i: Accident Analysis and Prevention. - : Elsevier. - 0001-4575 .- 1879-2057. ; 184
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Tidskriftsartikel (refereegranskat)abstract
- While the negative effects of alcohol on driving performance are undisputed, it is unclear how driver attention, eye movements and visual information sampling are affected by alcohol consumption. A simulator study with 35 participants was conducted to investigate whether and how a driver's level of attention is related to self-paced non-driving related task (NDRT)-engagement and tactical aspects of undesirable driver behaviour under increasing levels of breath alcohol concentration (BrAC) up to 1.0 ‰. Increasing BrAC levels lead to more frequent speeding, short time headways and weaving, and higher NDRT engagement. Instantaneous distraction events become more frequent, with more and longer glances to the NDRT, and a general decline in visual attention to the forward roadway. With alcohol, the compensatory behaviour that is typically seen when drivers engage in NDRTs did not appear. These findings support the theory that alcohol reduces the ability to shift attention between multiple tasks. To conclude, the independent reduction in safety margins in combination with impaired attention and an increased willingness to engage in NDRTs is likely the reason behind increased crash risk when driving under the influence of alcohol. © 2023
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| 9. |
- Ahlström, Christer, 1977-, et al.
(författare)
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Development of sleepiness in professional truck drivers : Real‐road testing for driver drowsiness and attention warning (DDAW) system evaluation
- 2024
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Ingår i: Journal of Sleep Research. - : John Wiley & Sons. - 0962-1105 .- 1365-2869.
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Tidskriftsartikel (refereegranskat)abstract
- All new vehicle types within the European Union must now be equipped with a driver drowsiness and attention warning system starting from 2022. The specific requirements for the test procedure necessary for type approval are defined in the Annex of EU Regulation C/2021/2639. The objectives of this study were to: (i) investigate how sleepiness develops in professional truck drivers under real-road driving conditions; and (ii) assess the feasibility of a test procedure for validating driver drowsiness and attention warning systems according to the EU regulation. Twenty-four professional truck drivers participated in the test. They drove for 180 km on a dual-lane motorway, first during daytime after a normal night's sleep and then at nighttime after being awake since early morning. The results showed higher sleepiness levels during nighttime driving compared with daytime, with a faster increase in sleepiness with distance driven, especially during the night. Psychomotor vigilance task results corroborated these findings. From a driver drowsiness and attention warning testing perspective, the study design with sleep-deprived drivers at night was successful in inducing the targeted sleepiness level of a Karolinska Sleepiness Scale score of ≥ 8. Many drivers who reported a Karolinska Sleepiness Scale ≥ 8 during the drives also acknowledged feeling sleepy in the post-drive questionnaire. Reaching high levels of sleepiness on real roads during daytime is more problematic, not the least from legal and ethical perspectives as higher traffic densities during the daytime lead to increased risks.
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| 10. |
- Ahlström, Christer, et al.
(författare)
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Effects of partially automated driving on the development of driver sleepiness
- 2021
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Ingår i: Accident Analysis and Prevention. - : Elsevier BV. - 0001-4575 .- 1879-2057. ; 153
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this study was to compare the development of sleepiness during manual driving versus level 2 partially automated driving, when driving on a motorway in Sweden. The hypothesis was that partially auto-mated driving will lead to higher levels of fatigue due to underload. Eighty-nine drivers were included in the study using a 2 ? 2 design with the conditions manual versus partially automated driving and daytime (full sleep) versus night-time (sleep deprived). The results showed that night-time driving led to markedly increased levels of sleepiness in terms of subjective sleepiness ratings, blink durations, PERCLOS, pupil diameter and heart rate. Partially automated driving led to slightly higher subjective sleepiness ratings, longer blink durations, decreased pupil diameter, slower heart rate, and higher EEG alpha and theta activity. However, elevated levels of sleepiness mainly arose from the night-time drives when the sleep pressure was high. During daytime, when the drivers were alert, partially automated driving had little or no detrimental effects on driver fatigue. Whether the negative effects of increased sleepiness during partially automated driving can be compensated by the positive effects of lateral and longitudinal driving support needs to be investigated in further studies.
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