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Open AccessArticle

Assessing the Impact of 20 mph Speed Limits on Vehicle Speeds in Rural Areas: The Case of the Scottish Borders

by

Adebola Olowosegun

,

Grigorios Fountas

and

Adrian Davis

Safety 2023, 9(3), 66; https://doi.org/10.3390/safety9030066 - 13 Sep 2023

Viewed by 684

Abstract

This paper aims at delivering new empirical evidence as to the effectiveness of 20 mph speed limits in rural areas. For this purpose, speed and traffic data were drawn from the area of the Scottish Borders, UK, where the local Council led the [...] Read more.

This paper aims at delivering new empirical evidence as to the effectiveness of 20 mph speed limits in rural areas. For this purpose, speed and traffic data were drawn from the area of the Scottish Borders, UK, where the local Council led the rollout of a 20 mph speed limit trial in 97 villages and towns from October 2020. This intervention is considered as one of the first of its kind in the UK and overseas, as it was carried out on a large scale, in predominantly rural areas. To evaluate the impact of the 20 mph speed limit on vehicle speeds, we conducted a “before–after” quantitative analysis using traffic and speed data collected in different waves before and after the intervention. The descriptive analysis showed that both mean and 85th percentile speeds reduced directly after the introduction of the 20 mph speed limit (by 3.1 mph and 3.2 mph, respectively), and that such speed reductions were largely maintained even up to eight months after the onset of the intervention. The largest speed reductions were observed in locations with high-speed patterns before the intervention, and especially in those having mean speeds greater than 25 mph before the intervention. Both non-parametric and parametric statistical tests, which were conducted using approximately five million speed observations, showed that the observed speed changes were statistically significant for the vast majority of cases. Linear regression models were also estimated confirming the significant impact of the 20 mph limit on vehicle speeds, while controlling for the influence of traffic volume. Overall, the findings of this study will likely assist in filling an evidence gap regarding the effectiveness of 20 mph speed limits in rural settlements. They can also provide encouragement to those local authorities in the UK and abroad that are currently actively examining the possibility of setting the 20 mph as the default limit in built-up areas. Full article

(This article belongs to the Special Issue Human Factors in Road Safety and Mobility)

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Open AccessArticle

Infrastructure-Based Performance Evaluation for Low-Speed Automated Vehicle (LSAV)

by

Sheila Klauer

,

Yubin Hong

,

Mike Mollenhauer

and

Jean Paul Talledo Vilela

Safety 2023, 9(2), 30; https://doi.org/10.3390/safety9020030 - 05 May 2023

Viewed by 944

Abstract

This study assessed the limitations of the EasyMile EZ10 Gen 3 low-speed automated vehicle (LSAV) while operating on public roadways. The primary interest was to evaluate the infrastructure elements that posed the greatest challenges for the LSAV. A route was chosen that would [...] Read more.

This study assessed the limitations of the EasyMile EZ10 Gen 3 low-speed automated vehicle (LSAV) while operating on public roadways. The primary interest was to evaluate the infrastructure elements that posed the greatest challenges for the LSAV. A route was chosen that would satisfy a legitimate transit need. This route included more operational complexity and higher traffic volumes than a typical EasyMile LSAV deployment. The results indicate that the LSAV operated at a lower-than-expected speed (6 to 8 mph), with a high frequency of disengagements, and a regular need for safety operator intervention. Four-way stop-sign controlled intersections, three-lane roads with a shared turning lane in the middle, open areas, and areas without clear markings were the most challenging for the LSAV. Some important considerations include the need to have LSAVs operate on roadways where other vehicles may pass more safely, or on streets with slower posted speed limits. Additionally, the low passenger capacity and inability to understand where passengers are located onboard make it hard for the LSAV to replace bus transits. Currently, the LSAV is best suited to provide first/last-mile services, short routes within a controlled access area, and fill in gaps in conventional transits. Full article

(This article belongs to the Special Issue Human Factors in Road Safety and Mobility)

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Open AccessArticle

An Assessment of Horse-Drawn Vehicle Incidents from U.S. News Media Reports within AgInjuryNews

by

Nicole Becklinger

Safety 2023, 9(2), 21; https://doi.org/10.3390/safety9020021 - 02 Apr 2023

Viewed by 907

Abstract

Some old-order Anabaptist communities rely on animal-drawn vehicles for transportation and farm work. This research examines reports involving horse-drawn vehicles found in the AgInjuryNews dataset, which provides a publicly accessible collection of agricultural injury reports primarily gathered from news media. The goals of [...] Read more.

Some old-order Anabaptist communities rely on animal-drawn vehicles for transportation and farm work. This research examines reports involving horse-drawn vehicles found in the AgInjuryNews dataset, which provides a publicly accessible collection of agricultural injury reports primarily gathered from news media. The goals of this research are to characterize the reports and to compare results with previous research to assess the utility of using AgInjuryNews to examine horse-drawn vehicle incidents. A total of 38 reports representing 83 victims were identified. Chi-square tests comparing victim and incident traits for fatal and nonfatal injuries were significant for the victim’s role in the incident, vehicle type, presence of a motor vehicle, rear-ending by a motor vehicle, spooked horses, a victim being run over or struck by a vehicle, and a victim being ejected or falling from a vehicle. Additional analysis of incidents involving horse-drawn farm equipment showed that a significantly higher proportion of off-road incidents were fatal compared to on-road incidents. The proportion of fatal injuries in the AgInjuryNews dataset was approximately 10 times higher than observed in a study using Pennsylvania Department of Transportation (DOT) data. Compared to previous research, the AgInjuryNews reports contained a higher proportion of incidents where a motor vehicle rear-ended a horse-drawn vehicle, and fewer cases of horse-drawn vehicles being struck by motor vehicles while crossing or entering a main road and making left turns. Reports of buggy crashes found in AgInjuryNews differed from those found in a Nexis Uni search in that the bulk of the articles from Nexis Uni referred to cases involving criminal charges for impaired driving or hit-and-run crashes. While it is evident that the reports included in the sample are incidents that media sources find compelling rather than comprehensive injury surveillance, it is possible to gain new insights using the AgInjuryNews reports. Full article

(This article belongs to the Special Issue Human Factors in Road Safety and Mobility)

Open AccessArticle

Fatigue and Secondary Media Impacts in the Automated Vehicle: A Multidimensional State Perspective

by

Catherine E. Neubauer

,

Gerald Matthews

and

Erika P. De Los Santos

Safety 2023, 9(1), 11; https://doi.org/10.3390/safety9010011 - 23 Feb 2023

Viewed by 1130

Abstract

Safety researchers increasingly recognize the impacts of task-induced fatigue on vehicle driving behavior. The current study (N = 180) explored the use of a multidimensional fatigue measure, the Driver Fatigue Questionnaire (DFQ), to test the impacts of vehicle automation, secondary media use, and [...] Read more.

Safety researchers increasingly recognize the impacts of task-induced fatigue on vehicle driving behavior. The current study (N = 180) explored the use of a multidimensional fatigue measure, the Driver Fatigue Questionnaire (DFQ), to test the impacts of vehicle automation, secondary media use, and driver personality on fatigue states and performance in a driving simulator. Secondary media included a trivia game and a cellphone conversation. Simulated driving induced large-magnitude fatigue states in participants, including tiredness, confusion, coping through self-comforting, and muscular symptoms. Consistent with previous laboratory and field studies, dispositional fatigue proneness predicted increases in state fatigue during the drive, especially tiredness, irrespective of automation level and secondary media. Similar to previous studies, automation slowed braking response to the emergency event following takeover but did not affect fatigue. Secondary media use relieved subjective fatigue and improved lateral control but did not affect emergency braking. Confusion was, surprisingly, associated with faster braking, and tiredness was associated with impaired control of lateral position of the vehicle. These associations were not moderated by the experimental factors. Overall, data support the use of multidimensional assessments of both fatigue symptoms and information-processing components for evaluating safety impacts of interventions for fatigue. Full article

(This article belongs to the Special Issue Human Factors in Road Safety and Mobility)

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Open AccessArticle

The Effect of Driving Style on Responses to Unexpected Vehicle Cyberattacks

by

,

,

and

Safety 2023, 9(1), 5; https://doi.org/10.3390/safety9010005 - 31 Jan 2023

Viewed by 1530

Abstract

Vehicle cybersecurity is a serious concern, as modern vehicles are vulnerable to cyberattacks. How drivers respond to situations induced by vehicle cyberattacks is safety critical. This paper sought to understand the effect of human drivers’ risky driving style on response behavior to unexpected [...] Read more.

Vehicle cybersecurity is a serious concern, as modern vehicles are vulnerable to cyberattacks. How drivers respond to situations induced by vehicle cyberattacks is safety critical. This paper sought to understand the effect of human drivers’ risky driving style on response behavior to unexpected vehicle cyberattacks. A driving simulator study was conducted wherein 32 participants experienced a series of simulated drives in which unexpected events caused by vehicle cyberattacks were presented. Participants’ response behavior was assessed by their change in velocity after the cybersecurity events occurred, their post-event acceleration, as well as time to first reaction. Risky driving style was portrayed by scores on the Driver Behavior Questionnaire (DBQ) and the Brief Sensation Seeking Scale (BSSS). Half of the participants also received training regarding vehicle cybersecurity before the experiment. Results suggest that when encountering certain cyberattack-induced unexpected events, whether one received training, driving scenario, participants’ gender, DBQ-Violation scores, together with their sensation seeking measured by disinhibition, had a significant impact on their response behavior. Although both the DBQ and sensation seeking have been constantly reported to be linked with risky and aberrant driving behavior, we found that drivers with higher sensation seeking tended to respond to unexpected driving situations induced by vehicle cyberattacks in a less risky and potentially safer manner. This study incorporates not only human factors into the safety research of vehicle cybersecurity, but also builds direct connections between drivers’ risky driving style, which may come from their inherent risk-taking tendency, to response behavior to vehicle cyberattacks. Full article

(This article belongs to the Special Issue Human Factors in Road Safety and Mobility)

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Open AccessArticle

Impact of Temporary Browsing Restrictions on Drivers’ Situation Awareness When Interacting with In-Vehicle Infotainment Systems

by

Jason Meyer

,

Eddy Llaneras

and

Gregory M. Fitch

Safety 2022, 8(4), 81; https://doi.org/10.3390/safety8040081 - 07 Dec 2022

Viewed by 1278

Abstract

Looking away from the road during a task degrades situation awareness of potential hazards. Long glances back to the road rebuild this awareness and are thought to be critical for maintaining good vehicle control and recognizing conflicts. To further investigate the importance of [...] Read more.

Looking away from the road during a task degrades situation awareness of potential hazards. Long glances back to the road rebuild this awareness and are thought to be critical for maintaining good vehicle control and recognizing conflicts. To further investigate the importance of rebuilding situation awareness, a controlled test-track study was performed that evaluated drivers’ hazard awareness and response performance to a surprise event after completing a task that involved pausing partway through it to look back at the road. Thirty-two drivers completed a visual-manual infotainment system secondary task. Half of the drivers were instructed to pause their browsing mid-task, while the others were not. While the task was being performed, a lead vehicle activated its hazard lights. It then unexpectedly dropped a fake muffler once drivers completed the task. Drivers’ visual attention to the road and their ability to respond to the muffler were measured. The drivers that paused their browsing were more aware of the lead vehicle’s hazard lights, showed less surprise to the dropped muffler, and executed more measured avoidance maneuvers compared to the drivers that did not pause their browsing. These findings suggest that drivers’ situation awareness can be better maintained when task interactions are paced, allowing for longer monitoring of the environment. Mechanisms that encourage drivers to take restorative on-road glances during extended browsing may be a key aspect of an overall approach to mitigating driver distraction. Full article

(This article belongs to the Special Issue Human Factors in Road Safety and Mobility)

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Open AccessArticle

Modeling the Impact of Driving Styles on Crash Severity Level Using SHRP 2 Naturalistic Driving Data

by

Kuan-Ting Chen

and

Huei-Yen Winnie Chen

Safety 2022, 8(4), 74; https://doi.org/10.3390/safety8040074 - 05 Nov 2022

Viewed by 1384

Abstract

Previous studies have examined driving styles and how they are associated with crash risks relying on self-report questionnaires to categorize respondents based on pre-defined driving styles. Naturalistic driving studies provide a unique opportunity to examine this relationship differently. The current study aimed to [...] Read more.

Previous studies have examined driving styles and how they are associated with crash risks relying on self-report questionnaires to categorize respondents based on pre-defined driving styles. Naturalistic driving studies provide a unique opportunity to examine this relationship differently. The current study aimed to study how driving styles, derived from real-road driving, may relate to crash severity. To study the relationship, this study retrieved safety critical events (SCEs) from the SHRP 2 database and adopted joint modelling of the number of the aggregated crash severity levels (crash vs. non-crash) using the Diagonal Inflated Bivariate Poisson (DIBP) model. Variables examined included driving styles and various driver characteristics. Among driving styles examined, styles of maintenance of lower speeds and more adaptive responses to driving conditions were associated with fewer crashes given an SCE occurred. Longer driving experiences, more miles driven last year, and being female also reduced the number of crashes. Interestingly, older drivers were associated with both an increased number of crashes and increased number of non-crash SCEs. Future work may leverage more variables from the SHRP 2 database and widen the scope to examine different traffic conditions for a more complete picture of driving styles. Full article

(This article belongs to the Special Issue Human Factors in Road Safety and Mobility)

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Review

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Open AccessReview

Augmented Reality for Vehicle-Driver Communication: A Systematic Review

by

Liam Kettle

and

Yi-Ching Lee

Safety 2022, 8(4), 84; https://doi.org/10.3390/safety8040084 - 13 Dec 2022

Cited by 2 | Viewed by 2339

Abstract

Capabilities for automated driving system (ADS)-equipped vehicles have been expanding over the past decade. Research has explored integrating augmented reality (AR) interfaces in ADS-equipped vehicles to improve drivers’ situational awareness, performance, and trust. This paper systematically reviewed AR visualizations for in-vehicle vehicle-driver communication [...] Read more.

Capabilities for automated driving system (ADS)-equipped vehicles have been expanding over the past decade. Research has explored integrating augmented reality (AR) interfaces in ADS-equipped vehicles to improve drivers’ situational awareness, performance, and trust. This paper systematically reviewed AR visualizations for in-vehicle vehicle-driver communication from 2012 to 2022. The review first identified meta-data and methodological trends before aggregating findings from distinct AR interfaces and corresponding subjective and objective measures. Prominent subjective measures included acceptance, trust, and user experience; objective measures comprised various driving behavior or eye-tracking metrics. Research more often evaluated simulated AR interfaces, presented through windshields, and communicated object detection or intended maneuvers, in level 2 ADS. For object detection, key visualizations included bounding shapes, highlighting, or symbols. For intended route, mixed results were found for world-fixed verse screen-fixed arrows. Regardless of the AR design, communicating the ADS’ actions or environmental elements was beneficial to drivers, though presenting clear, relevant information was more favorable. Gaps in the literature that yet to be addressed include longitudinal effects, impaired visibility, contextual user needs, system reliability, and, most notably, inclusive design. Regardless, the review supports that integrating AR interfaces in ADS-equipped vehicles can lead to higher trust, acceptance, and safer driving performances. Full article

(This article belongs to the Special Issue Human Factors in Road Safety and Mobility)

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