The influence of LED road stud color on driver behavior and perception along horizontal curves at nighttime

Scotopic lighting conditions (reduced level of natural light or presence of artificial lighting) may impair driving performance and, therefore, impact on road safety. Thanks to technological developments, low-cost light emitting diode (LED) studs are now being considered as an alternative and affordable pavement marking solution to assist drivers in these conditions. By helping them to maintain their vehicle within the marked lane, the studs should prevent any deterioration in driver performance when negotiating curves at nighttime. However, the few studies that investigated the impact of LED studs on driving performance produced inconsistent results, and the question of whether they actively improve driver performance remains open. Furthermore, while international road regulations allow the use of LED studs, they do not provide consistent prescriptions for their lighting color.Here, we assessed the influence of different LED lighting colors (red, white, and unlit) on longitudinal and transversal driver behavior when negotiating road curves with different radii and sense of direction. In the study, thirty-six drivers drove a dynamic virtual scenario featuring twenty-four curves. After the driving simulation, participants completed a static perception test in which they assessed each curve in terms of the perceived levels of risk, pleasantness, and arousal they experienced while driving on it.In comparison with the unlit and red lit curves, those marked with white lighting LED studs were perceived as less risky, less arousing, and more pleasant independently of the radii and curve direction. Furthermore, when entering these curves, participants tended to shift their driving trajectories towards the center of the road. This effect was most evident on the central part of the curve. Further studies are expected to corroborate these results by focusing on different road geometries and LED stud layouts, as well as testing driving behavior in controlled road field studies

The effect of traffic light spacing and signal congruency on drivers’ responses at urban intersections

Traffic lights are critical in regulating traffic flow and modulate the level of service and road user safety. As suggested by studies conducted with pedestrians, traffic light spacing and signal congruency could also impact a driver's decision-making process. However, requirements related to designing signalized intersections do not always consider the spacing between two consecutive traffic lights or the congruency of the information displayed. Here, using a classic traffic psychology paradigm, we developed a hybrid Go/No-go Flanker PC-based task to explore how traffic light spacing and signal congruency modulate drivers’ decisions in urban intersections. Real images of road intersections were edited to reproduce two specific conditions between traffic lights. Specifically, we manipulated both spacing (short vs. long) and congruency (congruent [e.g., red-red/green-green steady light] vs. incongruent [e.g., red-green/green-red steady light]). We found that incongruent information, displayed on short spacing traffic signals, delayed drivers’ responses without being detrimental to their decision-making processes. The results of this exploratory study could offer guidance to transportation engineers to simplify traffic light information readability and increase drivers’ awareness of traffic conditions and road safety

Phylogenetic analysis of porcine circovirus type 2 in Sardinia, Italy, shows genotype 2d circulation among domestic pigs and wild boars

Abstract Porcine circovirus type 2 (PCV2) is associated with multi-factorial syndromes, commonly known as porcine-circovirus–associated diseases, which cause severe economic losses in the swine industry worldwide. Four genotypes (PCV2a, PCV2b, PCV2c, and PCV2d) have been identified. Lately, the prevalence of PCV2d has been increasing in many countries, thereby prefiguring a global replacement of PCV2b. Wild boars are also susceptible to PCV2 infection, with virus prevalence similar to that of domestic pigs. This work was aimed at expanding the knowledge about the molecular epidemiology of PCV2 in Italy. For this purpose, we analysed 40 complete ORF-2 sequences from PCV2 strains isolated from domestic pigs and wild boars in Sardinia (Italy) over a period of 5 years (2009–2013). Phylogenetic and Bayesian analyses were performed on three data sets compiled from DNA sequences over a large geographical area. PCV2b was found to be dominant in Sardinia, whereas no PCV2a and PCV2c were found. This study indicates the presence of genotype PCV2d-2 infecting both domestic and wild pigs, thus confirming its circulation in Italy. Sardinian sequences clustered mostly with Italian isolates and with strains from China, Belgium, Croatia, Taiwan, Korea, and Portugal. Genetic variability of PCV2 in Sardinia appears to be a result of both local viral evolution and different epidemic introduction events

The implications of situation and route familiarity for driver-pedestrian interaction at uncontrolled mid-block crosswalks

Most routine daily trips take place along the same route, a fact that previous studies have not investigated together with the repeated situation of conflicting with other road users. Consequently, our study addresses driver behaviour by separating the driving experience into three categories: (i) drivers unfamiliar with the route, (ii) those route-familiar, and (iii) situation familiar drivers. The specific case of driver-pedestrian interaction at uncontrolled mid-block crosswalks is investigated. A multi-level factorial experiment including (i) crosswalk design (linear sidewalk and curb extension), (ii) driver familiarity, and (iii) pedestrian time gap acceptance (4, 6, and 8 s) was conducted using a driving simulator. Fifty-two participants were divided into four groups and stratified by age, gender, and driving experience. The minimum instantaneous time to collision, post-encroachment time, maximum car deceleration, and maximum car speed were all used as surrogate safety measures (SSM). Route-familiarity led to higher speed, while situation-familiarity positively affected driving behaviour making drivers more inclined to decrease their speed at circa 100 m before a crosswalk.The curb extension layout enhanced pedestrian safety and mitigated any adverse effects due to familiarity, with a particularly relevant impact on SSM at low accepted time gaps for pedestrians. Situation- and route-familiarity treatment protocols lead to different behaviours among drivers, indicating a clear need to account for these two familiarity levels in experiments on safety-related countermeasures

Short-term effects of in-vehicle napping on psychophysiological driver state and performance: An experimental study with partially sleep-deprived operators

Sleep Europe 2022 - The 26th Congress of the European Sleep Research Society [ESRS]International audienceTaking in-vehicle nap breaks is a popular advice to avoid sleepiness at the wheel. However, the effects of this sleepiness countermeasure on driving performance is not clear. Most of the scientific evidence on this matter comes from research in non-driving settings, such as aviation. Unfortunately, such results are domain-specific and translations to other settings may not be straightforward. Here, we assessed the effects of a short in-vehicle nap in operators with partial sleep deprivation

Driver Monitoring Systems in automated interactions: A real-time, thermographic-based algorithm

International audienceDue to the progressive shift of responsibility from the driver to the vehicle itself in automated vehicle technologies, driver-centered innovations represent a key point for its advance. The so-called Driver Monitoring Systems (DMS) are therefore increasingly gaining importance in this context. One of the main aims of DMS is to estimate the drivers arousal levels in order to infer their cognitive state and capabilities. Even though the scientific literature is riddled with useful psychophysiological indices to estimate arousal levels [1], nowadays, arousal estimation is based on broad, mostly blink/gaze-related, indices. The reason is that actual implementation of reliable sensors in a feasible system able to collect, analyse, and interpret measurements in real-life conditions is still an open challenge. One of the alternatives to signal different cognitive states is facial skin temperature [2][3]. Infrared sensors that monitor heat loss have been shown useful to track facial skin temperature that indicate arousal modulations while driving [2][3]. Such intensive, laborious work to extract and analyse temperature changes in some facial landmarks is not reasonable in real-life applications [3]. Here, we present the preliminary results obtained with a new software able to track, in real-time, drivers facial-skin temperature changes. Also, we proved its usefulness in an automated driving condition

Physiological indices directory

Directory content: This directory contains 21 .CSV files with electrodermal activity (EDA), electrocardiogram (ECG), blood volume pulse (BVP), and respiration data (recorded at 400 Hz) for each driver (i.e., ID_Number_BiosignalsData). All files were pre-processed in two steps to ensure the correct sampling rate: (i) removing lines with timestamps repetitions, and (ii) resampled to 400 Hz using regularly spaced and linear interpolation. This directory also includes a .CSV file reporting the data description (Legend_DataBiosignal).Method and instruments: We used a BiosignalsPlux Research Kit (PLUX Wireless Biosignals, Lisbon, Portugal) to monitor participants’ ECG, BVP, EDA, and respiration data. The BiosignalsPlux system includes a wearable hub with an 8-channel configuration (analog ports) of 16-bit per channel resolution, using Bluetooth data transmission technology for synchronization with the driving simulator.We used disposable, self-adhesive, pre-gelled Ag/AgCl electrodes (24 mm diameter) for the ECG and EDA measurements. The EDA was recorded employing a dedicated single-lead local differential bipolar DC sensor (0-3 Hz bandwidth, 0-100 µS range), with two leads (a positive and a negative lead, 5.0 ± 0.5 cm length each), each one ending with a dedicated electrode socket. Once we cleaned the skin with an alcohol-free disinfectant, we placed the electrodes on the thenar (negative electrode) and hypothenar (positive electrode) eminences of the left hand. We made sure to let enough space on the hand palm between the two electrodes to minimize the risk of signal artifacts due to the pressure of the hand on the steering wheel. The ECG was recorded with a single-lead local differential bipolar sensor (0.5-100 Hz bandwidth, ± 1.47 mV range), including a positive, a negative, and a reference cable, each one ending with a dedicated electrode socket. Once we cleaned the skin, we placed the electrodes on the participant’s chest (Lead II configuration): one electrode on the depression below each of the shoulder blades (reference on the left side, positive on the right side) and one electrode (negative) on the fifth intercostal space of the left side.The BVP was measured through an optical, non-invasive ear-clip sensor (0.02-2.1 Hz bandwidth, 535±10 nm centroid wavelength), including a light emitter (LED) and detector. The sensor (LED and detector) was placed at the center of the left ear lobe.The respiration data was recorded using an elastic, adjustable chest belt that included a piezoelectric sensor (0.059-1 Hz bandwidth, ± 1.50 V range). We placed the belt on the participant’s chest, over a cotton short-sleeve T-shirt, ∼2 cm below the pectoral muscles, and connected to the hub using a dedicated cable of about 110 cm total length.</p

Subjective ratings directory

Directory content: This directory contains six .CSV files with screening (i.e., IDs ScreeningData) and subjective (i.e., IDs SubjectiveData; MEQr, SSS, BORG, NASA-TLX, MSAQ, for the acronyms see below) data. Data descriptions are reported in an .xlsx file (Legend_DataSubjective).Method and instruments: Through the experiment, we asked drivers to fill in seven questionnaires (digital format). First, we asked drivers to fill in a questionnaire aiming to collect sociodemographic data (e.g., age, handiness). Then, we used the reduced version of the Morningness – Eveningness Questionnaire (MEQr; Adan and Almirall, 1991) and the Spanish Driving Behavior Questionnaire (SDBQ; López de Cózar et al., 2006). The MEQr is a 5-item questionnaire assessing preferences in sleep-wake and activity schedule and allowing the classification of individuals into one of the following subtypes: definitely morning type (22–25 points); moderately morning type (18–21); neither type (12–17); moderately evening type (8–11); and definitely evening type (4–7). The SDBQ is a 34-item questionnaire that allows the identification of adaptive and maladaptive driving styles. Drivers answered the SDBQ items on a Likert scale ranging from 0 (never) to 10 (always).To assess the drivers’ perceived sleepiness and fatigue in three separate measuring times (i.e., pre-driving session, after 90-min of driving, and at the end of the session [after ∼ 180-min]), we administered the Standford Sleepiness Scale (SSS; Hoddes et al., 1973) and the Borg Scale of Perceived Exertion (BORG; Borg, 1998). The SSS provides a global measure of how alert a person is feeling, ranging between 1 and 7. The BORG indicates the level of fatigue, and consists of a numerical scale (ranging from 6 to 20) anchored by “not exertion at all” (score 6) to “maximal exertion” (score 20). To fill both questionnaires after 90 minutes of driving, the participants used the dedicated tablet inside the simulator (for further details, see Driving simulator indices directory). If the vehicle was set in manual driving modality, drivers were instructed to temporarily stop the vehicle.At the end of the driving session, to assess the degree of task complexity and the level of motion sickness experienced, we used the NASA-Task Load Index (NASA-TLX; Hart, 2006) and the Motion Sickness Assessment Scale (MSAQ; Gianaros et al., 2001). The NASA-TLX assesses the task load through six bipolar dimensions: mental, physical, and temporal demand, own performance, effort, and frustration, using a total score between 0 and 100 (higher values indicate higher perceived task load). The MSAQ includes 16 brief statements describing the most common motion sickness symptoms (e.g., “I felt sick to my stomach”) using a Likert scale ranging from 1 (“not at all”) to 9 (“severely”).</p