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| 2. |
- Kjellman, Erik, 1988-, et al.
(författare)
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ROMA - State assessment of road markings in Denmark, Nor-way and Sweden : Results from 2018
- 2019
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Assessments of the performance of road markings is carried out regularly to various degrees in the Nordic countries. The main aim of the Nordic road marking assessment study is to show possible differences in road marking performance between Denmark, Norway and Sweden. Possible differences between road marking performance, dependent on region, country, type of road and AADT (Annual Average Daily Traffic) are studied. Furthermore, a comparison between the TEN-T and the non-TEN-T road network is made. As 2018 is the second year of the project, a comparison between the results for 2017 and 2018 is also made. A Nordic certification system for road marking materials has recently been introduced in Norway and Denmark and will be introduced in Sweden 2019. This means that a documented product approval (i.e. certification) will be required for use of the material on roads managed by the national road authorities. The requirements are introduced successively as the existing contracts expire. Therefore, one aim is also to study the road marking quality before and under the introduction of the new certification requirements. Continuous assessments give the opportunity to react and adjust the requirements in the future, if the performance does not develop as expected. The study is based on physical mobile road assessment measurements carried out in Denmark, Norway and Sweden by Ramböll. In total 71 road objects were measured in Denmark, 124 in Norway and 434 in Sweden. The following variables were studied: retroreflectivity of dry and wet road markings, relative visibility of dry and wet road markings, relative pre-view-time (pvt) of dry and wet road markings and cover index.
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| 3. |
- Nygårdhs, Sara, 1979-, et al.
(författare)
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Machine-readability of road markings in the Nordic countries
- 2023
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The project AVRM (autonomous vehicles and road markings) aimed to examine how vehicles’ advanced driver assistance systems (ADAS) are constructed, how they function and how they detect road markings on the Nordic road network. Focus was on the systems lane departure warning (LDW) and lane keeping assist (LKA).Both the literature study and the interview study concluded that if the human eye can detect the road marking, then the road marking is machine-readable. However, only a few studies had been conducted in wet conditions relating machine-readability to road marking functionality.The pilot study aimed to test equipment and to find a method to connect machine-readability data with contrast ratio under various weather and light conditions, and to reveal possible problems before conduction of a main study. Results from both the literature study and the pilot study pointed out that wear and lack of road markings were the parameters related to road markings per se that contributed to poor machine-readability.The analysis showed that in daylight, there was no strong relationship between machine-readability and conventional road marking performance parameters. In addition, machine-readability was higher on multilane roads (99%) compared to on two-lane roads (93%), which may be explained for example by fewer curves on larger roads. Although data showed that machine-readability of broken lines was somewhat worse than that of solid lines of line width 0.1 m, this could be an effect of factors related to the (minor) roads where broken lines with 0.1 m width are commonly used.In sum, there are many factors unrelated to road markings that influence machine-readability. There are no clear relationships between machine-readability and conventional performance parameters. It should also be kept in mind that since retroreflectivity is a parameter measuring the performance in night-time, it could not be expected to affect daylight readability. As long as the road markings are visible for the human eye, they can be expected to be machine-readable as well.
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| 4. |
- Sandberg, David, 1980, et al.
(författare)
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The Characteristics of Sleepiness During Real Driving at Night - A Study of Driving Performance, Physiology and Subjective Experience
- 2011
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Ingår i: Sleep. - 1550-9109 .- 0161-8105. ; 34:10, s. 1317-1325
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Tidskriftsartikel (refereegranskat)abstract
- Study Objectives: Most studies of sleepy driving have been carried out in driving simulators. A few studies of real driving are available, but these have used only a few sleepiness indicators. The purpose of the present study was to characterize sleepiness in several indicators during real driving at night, compared with daytime driving. Design: Participants drove 55 km (at 90km/h) on a 9-m-wide rural highway in southern Sweden. Daytime driving started at 09: 00 or 11: 00 (2 groups) and night driving at 01: 00 or 03: 00 (balanced design). Setting: Instrumented car on a real road in normal traffic. Participants: Eighteen participants drawn from the local driving license register. Interventions: Daytime and nighttime drives. Measurement and Results: The vehicle was an instrumented car with video monitoring of the edge of the road and recording of the lateral position and speed. Electroencephalography and electrooculography were recorded, together with ratings of sleepiness every 5 minutes. Pronounced effects of night driving were seen for subjective sleepiness, electroencephalographic indicators of sleepiness, blink duration, and speed. Also, time on task showed significant effects for subjective sleepiness, blink duration, lane position, and speed. Sleepiness was highest toward the end of the nighttime drive. Night driving caused a leftward shift in lateral position and a reduction of speed. The latter two findings, as well as the overall pattern of sleepiness indicators, provide new insights into the effects of night driving. Conclusion: Night driving is associated with high levels of subjective, electrophysiologic, and behavioral sleepiness.
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| 5. |
- Vadeby, Anna, 1969-, et al.
(författare)
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ROMA - state assessment of road markings in Denmark, Norway and Sweden : Results from 2019
- 2020
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Assessments of the performance of road markings is carried out regularly to various degrees in the Nordic countries. The main aim of the Nordic road marking assessment study is to show possible differences in road marking performance between Denmark, Norway and Sweden. Possible differences between road marking performance, dependent on region, country, type of road and AADT (Annual Average Daily Traffic) are studied. Furthermore, a comparison between the TEN-T and the non-TEN-T road network is made. As 2019 is the third year of the project, a comparison between the results for 2017, 2018 and 2019 is also made. A Nordic certification system for road marking materials has recently come into force. In Denmark it started in 2017, in Norway 2018 and in Sweden in 2019. This means that a documented product approval (i.e. certification) will be required for the material used on roads managed by the national road authorities. The requirements are introduced successively as the existing contracts expire. Therefore, one aim is also to study the road marking quality before and under the introduction of the new certification requirements. Continuous assessments give the opportunity to react and adjust the requirements in the future, if the performance does not develop as expected. The study is based on physical mobile road assessment measurements carried out in Denmark, Norway and Sweden by Ramböll. In total 71 road objects were measured in Denmark, 124 in Norway and 500 in Sweden. The following variables were studied: retroreflectivity of dry and wet road markings, relative visibility of dry and wet road markings, relative pre-view-time (pvt) of dry and wet road markings and cover index.
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| 6. |
- Vadeby, Anna, 1969-, et al.
(författare)
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ROMA - state assessment of road markings in Denmark, Norway and Sweden : Final report
- 2022
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Assessments of the performance of road markings are carried out regularly to various degrees in the Nordic countries. The main aim of the Nordic road marking assessment (ROMA) study is to show possible differences in road marking performance between Denmark, Norway and Sweden. Possible differences between road marking performance, dependent on region, country, type of road and AADT (Annual Average Daily Traffic) are studied during the years 2017–2021. Furthermore, a comparison between the Trans-European Transport Network (TEN-T) and the non-TEN-T road network is made. A Nordic certification system for road marking materials was introduced in 2015. This means that a documented product approval (i.e., certification) is required for materials used on roads managed by the national road authorities. The requirements have been introduced successively in Denmark (since 2017), Norway (since 2018) and Sweden (since 2019) as the existing contracts expire. Therefore, one aim is also to study the road marking quality before and during the introduction of the new certification requirements. Continuous assessments give the opportunity to react and adjust the requirements in the future if the performance does not develop as expected. The study is based on physical mobile road assessment measurements carried out in Denmark, Norway, and Sweden by Ramboll during five years, 2017–2021. The following variables were studied: retroreflectivity of dry and wet road markings, relative visibility of dry and wet road markings, relative pre-view-time (pvt) of dry and wet road markings and cover index.
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| 7. |
- Vadeby, Anna, 1969-, et al.
(författare)
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ROMA - state assessment of road markings in Denmark, Norway and Sweden : Results from 2020
- 2021
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Assessments of the performance of road markings is carried out regularly to various degrees in the Nordic countries. The main aim of the Nordic road marking assessment study is to show possible differences in road marking performance between Denmark, Norway and Sweden. Possible differences between road marking performance, dependent on region, country, type of road and AADT (Annual Average Daily Traffic) are studied. Furthermore, a comparison between the Trans-European Transport Network (TEN-T) and the non-TEN-T road network is made. As 2020 is the fourth year of the project, a comparison between the results for 2017, 2018, 2019 and 2020 is also made. A Nordic certification system for road marking materials has recently come into force. In Denmark it started in 2017, in Norway 2018 and in Sweden in 2019. This means that a documented product approval (i.e. certification) will be required for the material used on roads managed by the national road authorities. The requirements are introduced successively as the existing contracts expire. Therefore, one aim is also to study the road marking quality before and under the introduction of the new certification requirements. Continuous assessments give the opportunity to react and adjust the requirements in the future, if the performance does not develop as expected. The study is based on physical mobile road assessment measurements carried out in Denmark, Norway and Sweden by Ramboll. In total 71 road objects were measured in Denmark, 123 in Norway and 430 in Sweden. The following variables were studied: retroreflectivity of dry and wet road markings, relative visibility of dry and wet road markings, relative pre-view-time (pvt) of dry and wet road markings and cover index.
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| 8. |
- Vadeby, Anna, 1969-, et al.
(författare)
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ROMA - state assessment of road markings in Denmark, Norway and Sweden : results from 2021
- 2022
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Assessments of the performance of road markings is carried out regularly to various degrees in the Nordic countries. The main aim of the Nordic road marking assessment (ROMA) study is to show possible differences in road marking performance between Denmark, Norway and Sweden. Possible differences between road marking performance, dependent on region, country, type of road and AADT (Annual Average Daily Traffic) are studied. Furthermore, a comparison between the Trans-European Transport Network (TEN-T) and the non-TEN-T road network is made. The year 2021 is the fifth year of the project, and a comparison between the results for 2017, 2018, 2019, 2020 and 2021 is also made. A Nordic certification system for road marking materials was introduced in 2015. This means that a documented product approval (i.e., certification) will be required for the material used on roads managed by the national road authorities. The requirements have been introduced successively in Denmark (since 2017), Norway (since 2018) and Sweden (since 2019) as the existing contracts expire. Therefore, one aim is also to study the road marking quality before and under the introduction of the new certification requirements. Continuous assessments give the opportunity to react and adjust the requirements in the future, if the performance does not develop as expected. The study is based on physical mobile road assessment measurements carried out in Denmark, Norway and Sweden by Ramboll. In total 71 road objects were measured in Denmark, 123 in Norway and 454 in Sweden in 2021. The following variables were studied: retroreflectivity of dry and wet road markings, relative visibility of dry and wet road markings, relative preview-time (pvt) of dry and wet road markings and cover index.
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| 9. |
- Hallvig, David, et al.
(författare)
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Real driving at night - predicting lane departures from physiological and subjective sleepiness
- 2014
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Ingår i: Biological Psychology. - : Elsevier BV. - 0301-0511 .- 1873-6246. ; 101, s. 18-23
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Tidskriftsartikel (refereegranskat)abstract
- Only limited information is available on how driving performance relates to physiological and subjective sleepiness on real roads. This relation was the focus of the present study. 33 volunteers drove for 90min on a rural road during the afternoon and night in an instrumented car, while electroencephalography and electrooculography and lane departures were recorded continuously and subjective ratings of sleepiness were made every 5min (Karolinska Sleepiness Scale - KSS). Data was analyzed using Bayesian multilevel modeling. Unintentional LDs increased during night driving, as did KSS and long blink durations(LBD). Lateral position moved to the left . LDs were predicted by self-reported sleepiness and LBDs across time and were significantly higher in individuals with high sleepiness. Removal of intentional LDs, enhanced the KSS/LD relation. It was concluded that LDs, KSS, and LBDs are strongly increased during night driving and that KSS predicts LDs.
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| 10. |
- Ahlström, Christer, 1977-, et al.
(författare)
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Effects of the road environment on the development of driver sleepiness in young male drivers
- 2018
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Ingår i: Accident Analysis and Prevention. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0001-4575 .- 1879-2057. ; 112, s. 127-134
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Tidskriftsartikel (refereegranskat)abstract
- Latent driver sleepiness may in some cases be masked by for example social interaction, stress and physical activity. This short-term modulation of sleepiness may also result from environmental factors, such as when driving in stimulating environments. The aim of this study is to compare two road environments and investigate how they affect driver sleepiness. Thirty young male drivers participated in a driving simulator experiment where they drove two scenarios: a rural environment with winding roads and low traffic density, and a suburban road with higher traffic density and a more built-up roadside environment. The driving task was essentially the same in both scenarios, i.e. to stay on the road, without much interaction with other road users. A 2 x 2 design, with the conditions rural versus suburban, and daytime (full sleep) versus night-time (sleep deprived), was used. The results show that there were only minor effects of the road environment on subjective and physiological indicators of sleepiness. In contrast, there was an increase in subjective sleepiness, longer blink durations and increased EEG alpha content, both due to time on task and to night-time driving. The two road environments differed both in terms of the demand on driver action and of visual load, and the results indicate that action demand is the more important of the two factors. The notion that driver fatigue should be countered in a more stimulating visual environment such as in the city is thus more likely due to increased task demand rather than to a richer visual scenery. This should be investigated in further studies.
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