This study investigates the effect of two pavement markings (transverse rumble strips (TRS) and a backward pointing herringbone pattern (HP)) on speed and lateral control in and nearby curves. Two ...real-world curves with strong indications of a safety problem were replicated as realistic as possible in the simulator. Results show that both speed and lateral control differ between the curves. These behavioural differences are probably due to curve-related dissimilarities with respect to geometric alignment, cross-sectional design and speed limit. TRS and HP both influenced mean speed and mean acceleration/deceleration but not lateral control. TRS generated an earlier and more stable speed reduction than HP which induced significant speed reductions along the curve. The TRS gives drivers more time to generate the right expectations about the upcoming curve. When accidents occur primarily near the curve entry, TRS is recommended. The HP has the potential to reduce accidents at the curve end.
Practitioner Summary: Two pavement markings (transversal rumble strips and HP) nearby dangerous curves were investigated in the driving simulator. TRS generated an earlier and more stable speed reduction than HP which induced speed reductions along the curve. The TRS gives drivers more time to generate right expectations about the upcoming curve.
Driving simulator data can be sampled in function of distance (equally spaced) or time (with constant frequency). Consequently, the sampling data might have problems in the envisaged type of analysis ...(i.e. point location based analysis vs. zonal-based analysis). These issues are illustrated by means of five driving simulator datasets. The nearest sampled parameter value in the direct vicinity of the specific point is a very good proxy for the driving parameter value at the point of interest along the road. The analysis of driving parameters in zones requires a different approach. In summary, the interpolation technique is preferred over using raw sampled data to calculate mean parameter values. We introduce an equivalent time integral formula to compute the mean value of a driving parameter with respect to distance. Based on this paper, we demonstrate that it is very important to mention the data processing approach in driving simulator methodology.
► Road outside urban area is cognitively less demanding than inside the urban area. ► Curves decrease mean speed but increase SD acceleration/deceleration and SDLP. ► PDT performance indicated higher ...workload when curves were present. ► Gates locally reduced speed but increased SD of acceleration/deceleration and SDLP. ► Curves and gate constructions can improve traffic safety.
This study examined the impact of traffic calming measures (TCM) on major roads in rural and urban areas. More specifically we investigated the effect of gate constructions located at the entrance of the urban area and horizontal curves within the urban area on driving behavior and workload. Forty-six participants completed a 34km test-drive on a driving simulator with eight thoroughfare configurations, i.e., 2 (curves: present, absent)×2 (gates: present, absent)×2 (peripheral detection task (PDT): present, absent) in a within-subject design.
PDT performance (mean response time (RT) and hit rate) indicated that drivers experienced the road outside the urban area as cognitively less demanding relative to the more complex road environment inside the urban area. Whereas curves induced a speed reduction that was sustained throughout the entire urban area, variability of acceleration/deceleration and lateral position were increased. In addition, PDT performance indicated higher workload when curves were present (versus absent). Gate constructions locally reduced speed (i.e., shortly before and after the entrance) and slightly increased variability of acceleration/deceleration and lateral position nearby the entrance. However, the effects on SDL-A/D and SDLP are too small to expect traffic safety problems.
It can be concluded that both curves and gate constructions can improve traffic safety. Notwithstanding, the decision to implement these measures will depend on contextual factors such as whether the road serves a traffic-, rather than a residential function.
•Participants are repeatedly exposed to a gate construction in a driving simulator.•Gates induced a local speed reduction that sustained over the five-day period.•Participants accelerated again after ...the gate to continue close to the speed limit.•Standard deviation of acceleration/deceleration was not influenced by the gates.•Gates did not affect standard deviation of lateral position.
Accident statistics show that transitions from rural to urban areas are accident prone locations. Inappropriate speed and mental underload have been identified as important causal factors nearby such transitions. A variety of traffic calming measures (TCM) near rural–urban transitions has been tested in field experiments and driving simulator studies. Simulator experiments repeatedly exposing participants to the same treatment are scarce, hence it is unclear to what extent the effects of a TCM endure over time.
This is precisely the objective of the current study: to examine what happens with the behavior of drivers when they are exposed multiple times to the same treatment (in this case a gate construction located at a rural–urban transition). Over a period of five successive days, seventeen participants completed a 17km test-drive on a driving simulator with two thoroughfare configurations (gates present or absent) in a within-subject design. Results indicate that gates induced a local speed reduction that sustained over this five-day period. Even though participants were inclined to accelerate again once passed by this gate configuration, they always kept driving at an appropriate speed. We did not find any negative side effects on SD of acceleration/deceleration or SDLP.
Overall we conclude that gate constructions have the potential to improve traffic safety in the direct vicinity of rural–urban transitions, even if drivers are repeatedly exposed. Notwithstanding, we advise policy makers to appropriately use this measure. Best is to always carefully consider the broader situational context (such as whether the road serves a traffic- rather than a residential function) of each particular location where the implementation of a gate construction is one of the options.
This study used data from a driving simulator to identify the best car drivers in a sample and gain insight about the most problematic behavior of each driver. To this end, 38 participants varying in ...age and gender were enrolled to take part in a particular simulator scenario, curve taking. Based on a review of the literature, a driver's speed, acceleration, and lateral position are the three most important driving performance indicators. In the simulations, the three indicators were monitored at points before, during, and after a curve. As a widely accepted tool for performance monitoring, benchmarking, and policy analysis, the concept of composite indicators, which combines single indicators into one index score, was employed. The technique of data envelopment analysis, which is an optimization model for measuring the relative performance of a set of decision-making units, or drivers in this study, was used for the index construction. On the basis of the results, best performers were distinguished from underperforming drivers. Moreover, by analyzing the weights allocated to each indicator from the model, the most problematic parameter (such as lateral position) and point along the curve (such as at curve end) were identified for each driver; this process led to specific driver improvement recommendations (such as training programs).
Self-amplifying RNA vaccines may induce equivalent or more potent immune responses at lower doses compared to non-replicating mRNA vaccines via amplified antigen expression. In this paper, we ...demonstrate that 1 μg of an LNP-formulated dual-antigen self-amplifying RNA vaccine (ZIP1642), encoding both the S-RBD and N antigen, elicits considerably higher neutralizing antibody titers against Wuhan-like Beta B.1.351 and Delta B.1.617.2 SARS-CoV-2 variants compared to those of convalescent patients. In addition, ZIP1642 vaccination in mice expanded both S- and N-specific CD3+CD4+ and CD3+CD8+ T cells and caused a Th1 shifted cytokine response. We demonstrate that the induction of such dual antigen-targeted cell-mediated immune response may provide better protection against variants displaying highly mutated Spike proteins, as infectious viral loads of both Wuhan-like and Beta variants were decreased after challenge of ZIP1642 vaccinated hamsters. Supported by these results, we encourage redirecting focus toward the induction of multiple antigen-targeted cell-mediated immunity in addition to neutralizing antibody responses to bypass waning antibody responses and attenuate infectious breakthrough and disease severity of future SARS-CoV-2 variants.
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An LNP-formulated SARS-CoV-2 saRNA vaccine, encoding the internal nucleocapsid in addition to the S-RBD antigen, elicits both S-specific neutralizing antibody responses and dual-antigen specific CMI in mice. The vaccination of hamsters offers protection against both Wuhan-like and Beta variant SARS-CoV-2 despite reduced vaccine-induced anti-S neutralization efficiency against the latter.
Serological surveys offer the most direct measurement to define the immunity status for numerous infectious diseases, such as COVID-19, and can provide valuable insights into understanding ...transmission patterns. This study describes seroprevalence changes over time in the context of the Democratic Republic of Congo, where COVID-19 case presentation was apparently largely oligo- or asymptomatic, and vaccination coverage remained extremely low.
A cohort of 635 health care workers (HCW) from 5 health zones of Kinshasa and 670 of their household members was interviewed and sampled in 6 rounds between July 2020 and January 2022. At each round, information on risk exposure and a blood sample were collected. Serology was defined as positive when binding antibodies against SARS-CoV-2 spike and nucleocapsid proteins were simultaneously present.
The SARS-CoV-2 antibody seroprevalence was high at baseline, 17.3% (95% CI 14.4-20.6) and 7.8% (95% CI 5.5-10.8) for HCW and household members, respectively, and fluctuated over time, between 9% and 62.1%. Seropositivity was heterogeneously distributed over the health zones (p < 0.001), ranging from 12.5% (95% CI 6.6-20.8) in N'djili to 33.7% (95% CI 24.6-43.8) in Bandalungwa at baseline for HCW. Seropositivity was associated with increasing rounds adjusted Odds Ratio (aOR) 1.75 (95% CI 1.66-1.85), with increasing age aOR 1.11 (95% CI 1.02-1.20), being a female aOR 1.35 (95% CI 1.10-1.66) and being a HCW aOR 2.38 (95% CI 1.80-3.14). There was no evidence that HCW brought the COVID-19 infection back home, with an aOR of 0.64 (95% CI 0.46-0.91) of seropositivity risk among household members in subsequent surveys. There was seroreversion and seroconversion over time, and HCW had a lower risk of seroreverting than household members (aOR 0.60 (95% CI 0.42-0.86)).
SARS-CoV-2 IgG antibody levels were high and dynamic over time in this African setting with low clinical case rates. The absence of association with health profession or general risk behaviors and with HCW positivity in subsequent rounds in HH members, shows the importance of the time-dependent, and not work-related, force of infection. Cohort seroprevalence estimates in a 'new disease' epidemic seem insufficient to guide policy makers for defining control strategies.
Infection with SARS-CoV-2 in high-risk groups such as kidney transplant and dialysis patients is shown to be associated with a more serious course of the disease. Four years after the start of the ...COVID-19 pandemic, crucial knowledge on the immune responses in these patient groups is still lacking. Therefore, this study aimed at investigating the humoral immune response after a SARS-CoV-2 infection compared to vaccination as well as the evolution of immunoglobulins over time. Kidney transplant recipients, patients on haemodialysis or on peritoneal dialysis and healthy controls were included in this longitudinal multicenter study. SARS-CoV-2 anti-RBD, anti-NP and anti-S1S2 immunoglobulin G (IgG) and A (IgA) as well as the neutralizing antibody capacity were measured. Kidney transplant recipients had a significantly better humoral response to SARS-CoV-2 after infection (86.4%) than after a two-dose mRNA vaccination (55.8%) while seroconversion was comparable in patients on haemodialysis after infection (95.8%) versus vaccination (89.4%). In individuals without prior COVID-19, the IgG levels after vaccination were significantly lower in kidney transplant recipients when compared to all other groups. However, the IgA titres remained the highest in this patient group at each time point, both after infection and vaccination. A history COVID-19 was associated with higher antibody levels after double-dose vaccination in all patient categories and, while decreasing, titres remained high six months after double-dose vaccination. Kidney transplant recipients had a more robust humoral response to SARS-CoV-2 following infection compared to a two-dose mRNA vaccination, while patients on haemodialysis exhibited comparable seroconversion rates. Notably, individuals with prior COVID-19 exhibited higher IgG levels in response to vaccination. Hybrid immunity is thus the best possible defence against severe COVID-19 disease and seems also to hold up for these populations. Next, it is not clear whether the higher IgA levels in the kidney transplant recipients is beneficial for neutralizing SARS-CoV-2 or if it is a sign of disease severity.
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