Tradeoffs between safe/comfortable headways versus mobility-enhancing headways in an automated driving environment: preliminary insights using a driving simulator experiment
Purpose – The anticipated benefits of connected and autonomous vehicles (CAVs) include safety and mobility enhancement. Small headways between successive vehicles, on one hand, can cause increased capacity and throughput and thereby improve overall mobility. On the other hand, small headways can cau...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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Emerald Publishing
2021-12-01
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| Series: | Frontiers in Engineering and Built Environment |
| Subjects: | |
| Online Access: | https://www.emerald.com/insight/content/doi/10.1108/FEBE-05-2021-0025/full/pdf |
| _version_ | 1827907099408990208 |
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| author | Yujie Li Tiantian Chen Sikai Chen Samuel Labi |
| author_facet | Yujie Li Tiantian Chen Sikai Chen Samuel Labi |
| author_sort | Yujie Li |
| collection | DOAJ |
| description | Purpose – The anticipated benefits of connected and autonomous vehicles (CAVs) include safety and mobility enhancement. Small headways between successive vehicles, on one hand, can cause increased capacity and throughput and thereby improve overall mobility. On the other hand, small headways can cause vehicle occupant discomfort and unsafety. Therefore, in a CAV environment, it is important to determine appropriate headways that offer a good balance between mobility and user safety/comfort. Design/methodology/approach – In addressing this research question, this study carried out a pilot experiment using a driving simulator equipped with a Level-3 automated driving system, to measure the threshold headways. The Method of Constant Stimuli (MCS) procedure was modified to enable the estimation of two comfort thresholds. The participants (drivers) were placed in three categories (“Cautious,” “Neutral” and “Confident”) and 250 driving tests were carried out for each category. Probit analysis was then used to estimate the threshold headways that differentiate drivers' discomfort and their intention to re-engage the driving tasks. Findings – The results indicate that “Cautious” drivers tend to be more sensitive to the decrease in headways, and therefore exhibit greater propensity to deactivate the automated driving mode under a longer headway relative to other driver groups. Also, there seems to exist no driver discomfort when the CAV maintains headway up to 5%–9% shorter than the headways they typically adopt. Further reduction in headways tends to cause discomfort to drivers and trigger take over control maneuver. Research limitations/implications – In future studies, the number of observations could be increased further. Practical implications – The study findings can help guide specification of user-friendly headways specified in the algorithms used for CAV control, by vehicle manufacturers and technology companies. By measuring and learning from a human driver's perception, AV manufacturers can produce personalized AVs to suit the user's preferences regarding headway. Also, the identified headway thresholds could be applied by practitioners and researchers to update highway lane capacities and passenger-car-equivalents in the autonomous mobility era. Originality/value – The study represents a pioneering effort and preliminary pilot driving simulator experiment to assess the tradeoffs between comfortable headways versus mobility-enhancing headways in an automated driving environment. |
| first_indexed | 2024-03-13T01:05:12Z |
| format | Article |
| id | doaj.art-b3b00c39f71d4b6cbaafb5dda23f969b |
| institution | Directory Open Access Journal |
| issn | 2634-2499 2634-2502 |
| language | English |
| last_indexed | 2024-03-13T01:05:12Z |
| publishDate | 2021-12-01 |
| publisher | Emerald Publishing |
| record_format | Article |
| series | Frontiers in Engineering and Built Environment |
| spelling | doaj.art-b3b00c39f71d4b6cbaafb5dda23f969b2023-07-06T07:24:59ZengEmerald PublishingFrontiers in Engineering and Built Environment2634-24992634-25022021-12-011217318710.1108/FEBE-05-2021-0025Tradeoffs between safe/comfortable headways versus mobility-enhancing headways in an automated driving environment: preliminary insights using a driving simulator experimentYujie Li0Tiantian Chen1Sikai Chen2Samuel Labi3Purdue University, West Lafayette, Indiana, USAIndustrial and Systems Engineering, The Hong Kong Polytechnic University, Kowloon, ChinaPurdue University, West Lafayette, Indiana, USAPurdue University, West Lafayette, Indiana, USAPurpose – The anticipated benefits of connected and autonomous vehicles (CAVs) include safety and mobility enhancement. Small headways between successive vehicles, on one hand, can cause increased capacity and throughput and thereby improve overall mobility. On the other hand, small headways can cause vehicle occupant discomfort and unsafety. Therefore, in a CAV environment, it is important to determine appropriate headways that offer a good balance between mobility and user safety/comfort. Design/methodology/approach – In addressing this research question, this study carried out a pilot experiment using a driving simulator equipped with a Level-3 automated driving system, to measure the threshold headways. The Method of Constant Stimuli (MCS) procedure was modified to enable the estimation of two comfort thresholds. The participants (drivers) were placed in three categories (“Cautious,” “Neutral” and “Confident”) and 250 driving tests were carried out for each category. Probit analysis was then used to estimate the threshold headways that differentiate drivers' discomfort and their intention to re-engage the driving tasks. Findings – The results indicate that “Cautious” drivers tend to be more sensitive to the decrease in headways, and therefore exhibit greater propensity to deactivate the automated driving mode under a longer headway relative to other driver groups. Also, there seems to exist no driver discomfort when the CAV maintains headway up to 5%–9% shorter than the headways they typically adopt. Further reduction in headways tends to cause discomfort to drivers and trigger take over control maneuver. Research limitations/implications – In future studies, the number of observations could be increased further. Practical implications – The study findings can help guide specification of user-friendly headways specified in the algorithms used for CAV control, by vehicle manufacturers and technology companies. By measuring and learning from a human driver's perception, AV manufacturers can produce personalized AVs to suit the user's preferences regarding headway. Also, the identified headway thresholds could be applied by practitioners and researchers to update highway lane capacities and passenger-car-equivalents in the autonomous mobility era. Originality/value – The study represents a pioneering effort and preliminary pilot driving simulator experiment to assess the tradeoffs between comfortable headways versus mobility-enhancing headways in an automated driving environment.https://www.emerald.com/insight/content/doi/10.1108/FEBE-05-2021-0025/full/pdfAutonomous vehiclesAutomated driving systemConnected vehiclesDriver perceptionCar-following headway |
| spellingShingle | Yujie Li Tiantian Chen Sikai Chen Samuel Labi Tradeoffs between safe/comfortable headways versus mobility-enhancing headways in an automated driving environment: preliminary insights using a driving simulator experiment Frontiers in Engineering and Built Environment Autonomous vehicles Automated driving system Connected vehicles Driver perception Car-following headway |
| title | Tradeoffs between safe/comfortable headways versus mobility-enhancing headways in an automated driving environment: preliminary insights using a driving simulator experiment |
| title_full | Tradeoffs between safe/comfortable headways versus mobility-enhancing headways in an automated driving environment: preliminary insights using a driving simulator experiment |
| title_fullStr | Tradeoffs between safe/comfortable headways versus mobility-enhancing headways in an automated driving environment: preliminary insights using a driving simulator experiment |
| title_full_unstemmed | Tradeoffs between safe/comfortable headways versus mobility-enhancing headways in an automated driving environment: preliminary insights using a driving simulator experiment |
| title_short | Tradeoffs between safe/comfortable headways versus mobility-enhancing headways in an automated driving environment: preliminary insights using a driving simulator experiment |
| title_sort | tradeoffs between safe comfortable headways versus mobility enhancing headways in an automated driving environment preliminary insights using a driving simulator experiment |
| topic | Autonomous vehicles Automated driving system Connected vehicles Driver perception Car-following headway |
| url | https://www.emerald.com/insight/content/doi/10.1108/FEBE-05-2021-0025/full/pdf |
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