Passenger cognitive comfort, a low-stress psychological state driven by perceived safety during vehicle motion, has received limited real-world quantification, particularly for proxemic factors that are central to autonomous vehicle (AV) behavior design. Using an instrumented vehicle on a six-lane Indian expressway, this study analyzed 5,705 overtaking and being-overtaken events from 50 participants, combining immediate 7-point discomfort ratings with synchronized proxemic and kinematic measurements. Ratings were categorized into low (LD: 1–2), moderate (MD: 3–4), and high (HD: 5–7) discomfort using Rasch-based grouping. Cross-tabulation and Pearson chi-square tests confirmed significant associations between discomfort and all examined factors, with lateral clearance (LC) showing the strongest effect. A chi-square automatic interaction detection decision tree (10-fold cross-validated; 80.7% classification) identified LC as the dominant comfort envelope (χ 2 = 876.5, p < 0.01) with a sharp, nonlinear gradient. At LC ≤ 0.8 m, high discomfort reached 44.3% and MD+HD rose to 81.2%, whereas at LC > 3.3 m, high discomfort was eliminated (0.0%) and low discomfort increased to 95.0%. The model merged adjacent LC bands with statistically similar discomfort profiles, yielding interpretable clearance regimes. Within the intermediate regime (1.3–2.3 m), contextual moderation became critical: heavy goods vehicles (HGV) increased the likelihood of high discomfort, especially for rear-seat passengers (HD 13.9% vs. 7.3% front; ∼1.9×). For car/light commercial vehicle interactions, the maneuver type primarily affected low and moderate discomfort. These regime-based findings provide actionable rules for comfort-aware AV motion planning (such as clearance prioritization, HGV-aware behavior, occupant-sensitive tuning) and driver training (e.g., lateral buffer discipline), enhancing perceived safety and acceptance.
Equitable access to urban green space (UGS) is essential for urban well-being, yet transport systems may reinforce spatial inequalities. This study develops a hierarchical multimodal assessment framework that integrates walking, cycling, public transit, and driving into an improved Huff-based Gaussian two-step floating catchment area (GA2SFCA) method, incorporating door-to-door travel costs and 26 UGS quality indicators. The framework is applied to 4,290 residential complexes in the central urban area of Xi’an, China. The results show that when public transit is the sole mode, 69.55% of residents (7.36 million people) cannot reach a quality UGS within 20 min. After introducing walking and cycling as feeder modes to transit, this proportion drops to 0.75%, and the mean accessibility increases by 730% (from 0.0212 to 0.1759). Driving exhibits the lowest Gini coefficient (0.348), yet suburban areas experience a 10.9% rise in inequality under car-oriented scenarios, implying that the apparent advantage of private cars may obscure deeper inequities. Cycling alone achieves the highest mean accessibility (0.1813) among single modes and shows a relatively balanced spatial equality (Gini coefficient of 0.545). A sensitivity analysis indicates that Spearman’s rank correlation coefficients for accessibility rankings across different time thresholds (10–30 min) range from 0.49 to 0.83, suggesting that the core findings are robust to threshold selection. These findings suggest that improving walking, cycling, and transit connectivity may, to some extent, be more conducive to equitable UGS access than expanding motorized networks. The framework could serve as a supplementary tool for identifying UGS blind spots and informing planning decisions.
Preventing safety of navigation (SN) deficiencies is of critical importance in waterborne transport since the SN Code constitutes one of the most recurrent deficiency categories that serve as a basis for detention under port state controls (PSC). In pursuit of this objective, this study initially delineates and critically evaluates the interdependencies between a spectrum of influential determinants and deficiency types, as well as their respective contributions to detention occurrences attributable to the SN code. For this purpose, a data-driven Bayesian network model is developed based on 5,979 vessel detentions documented in the Black Sea Memorandum of Understanding (MoU) archives between January 2003 and December 2024. The novelty of this study lies in the integration of a probabilistic graphical modeling approach (tree augmented na & iuml;ve (TAN)-based Bayesian networks) with association rule mining to jointly capture both causal dependency structures and frequent co-occurrence patterns in PSC detention data, which has not been previously explored in the context of SN-focused deficiency analysis. Findings indicate that deficiencies related to labor conditions have the highest impact to explain ship detentions under the SN Code, increasing the likelihood by 16.1%, highlighting a strong interrelationship between crew welfare conditions and navigational safety performance. The study contributes methodologically by integrating Bayesian network learning (TAN) with association rule mining in a unified analytical framework for PSC detention analysis, and practically by providing a data-driven basis for targeted inspection prioritization and risk mitigation strategies for port authorities and maritime operators.
Previous research has not specifically compared friction resulting from salt brine direct liquid application (DLA) to solid salt application. This study sought to fill that gap by conducting field-based experiments with the support of two counties in Wisconsin. One direction of travel on multilane divided roadway segments was treated with salt brine DLA (study route), and the opposite direction was treated with dry solid salt (control route). Field experiments were conducted during 11 winter storms. Performance measures evaluated included vehicular speed, pavement friction (grip), travel disruption (TD), salt used, and time to bare/wet. Mean values from study/control routes and storm conditions were compared to baseline conditions through statistical tests or modeling. Friction measurements were evaluated through mixed-effects meta-regression modeling. The results indicated that friction at the study and control routes was statistically similar; however, salt usage at the study routes with salt brine DLA was between 40% and 72% less than at that control routes with solid salt. Using a limited number of storms, TD at the study routes was found to be between 8% and 39% lower than at the control routes, whereas time to bare/wet (subjective metric) was similar between the study and control routes. Therefore, with the limited data and conditions evaluated, the findings provided some evidence that salt brine DLA and solid salt performed comparably, but salt brine DLA used less salt.
In response to the inconsistency and lack of multidimensionality in existing evaluation methodologies for human–machine shared steering control (SSC) systems, an integrated approach that combines both objective and subjective evaluation methods is proposed. By analyzing the key subsystems within the SSC system, an objective evaluation method is developed, focusing on four critical dimensions: safety, reliability, comfort, and suitability. Specific indexes are defined to assess each dimension quantitatively, ensuring a systematic and comprehensive evaluation process. To complement the objective approach, a subjective evaluation method is formulated, addressing the same four dimensions. The subjective evaluation method incorporates weight coefficients for individual evaluation indexes; a detailed procedure for comprehensive evaluation is outlined, thereby enhancing the robustness and adaptability of the proposed framework. The effectiveness of the proposed methodology is validated through experimental trials and questionnaire surveys involving 32 drivers. The results demonstrate the feasibility of comparing the overall performance of different SSC systems using both objective and subjective evaluations. Furthermore, the strong consistency between the objective and subjective evaluation outcomes confirms the coherence, rationality, and practical suitability of the proposed approach, establishing its suitability for practical applications in SSC system assessment.
