Engineering

Abstract: We study the topology-dependent performance of scheduling-aware multipath routing in capacitated networks subject to congestion, node throughput constraints, downstream storage limits, and structural failure. We evaluate four routing strategies: shortest-path routing (SP), k-shortest paths (KSP), vertex-disjoint routing (VD), and a spillback-aware scheduling heuristic (VDSched). Experiments are conducted across five canonical synthetic topologies: grid, Erdős–Rényi random, scale-free, small-world, and spatial random networks, and four stress scenarios: baseline, random edge failure, targeted edge failure, and capacity degradation. The primary suite uses target n = 400-node networks, 50 origin–destination pairs per instance, 20 instances per topology across four graph-generation seeds, yielding 400 seed–instance realisations and 12,800 primary simulation runs. Statistical comparisons use paired Wilcoxon signed-rank tests with Holm correction.VDSched reduces peak blocked mass in every topology–scenario combination tested, with reductions of 36.5–87.0% relative to SP in the primary η = 5 suite. Its effect on mean delivery time, however, is strongly topology dependent. VDSched reduces mean delivery time by 18.9–23.6% in Erdős–Rényi random networks and by 31.6–36.7% in spatial random networks. In scale-free networks, it reduces delivery time by 9.8–10.4% under baseline, random-failure, and capacity-degradation scenarios, but provides no significant benefit under targeted removal of structurally important edges. In small-world networks, delivery-time gains are weaker and scenario-dependent, with the clearest benefit under capacity degradation.Grid networks reveal the opposite regime: VDSched increases mean delivery time by 1.5–3.4% relative to SP despite reducing peak blocked mass by 68.4–77.6%. This exposes a latency–congestion trade-off in topologies where alternative routes are geometrically inefficient. A storage-sensitivity analysis across η ∈ {3, 5, 8} confirms that these topology-dependent performance regimes are robust to variation in node storage capacity, with topology remaining the dominant moderator of delivery-time performance across all storage settings. These findings establish that VDSched is a robust congestion-suppression mechanism whose latency benefit depends on whether the topology provides efficient alternative routes.

Abstract: Micromobility has become an increasingly important part of sustainable urban transport, but its rapid expansion has also raised safety concerns for users who have limited physi-cal protection in the event of a crash. National-level evidence on micromobility safety re-mains limited in Central and Eastern Europe. This study therefore provides an epidemio-logical assessment of 836 micromobility-related crashes recorded in Hungary in 2024 us-ing administrative data from the Hungarian Central Statistical Office (KSH/HCSO). De-scriptive statistics were used to characterize injury severity, hourly crash occurrence, weather conditions, nature of accident, and road shape. Chi-square tests were then ap-plied to examine whether injury severity was associated with these temporal, environ-mental, and crash-context characteristics. For inferential analysis, injury severity was di-chotomized into slight versus serious/fatal injury. Monte Carlo permutation procedures were used to estimate p-values, and Cramér’s V was calculated to quantify the strength of association. Slight injuries accounted for 63.4% of recorded crashes, serious injuries for 35.8%, and fatal outcomes for 0.8%. Crash occurrence was concentrated in the afternoon, with 192 crashes (23.0%) recorded between 15:00 and 17:00 and the highest hourly fre-quency occurring at 16:00 (n = 79). Nature of accident was significantly associated with injury severity (χ²(11) = 26.36, p = 0.0037, Cramér’s V = 0.178), whereas weather condition, road shape, and hour of day were not. These findings identify crash mechanism as an important area of focus for future micromobility safety analysis and prevention.

Abstract: Reliable road-accident analysis requires attention to numerical stability, appropriate exposure treatment, and temporal validation in addition to predictive accuracy. This study presents an integrated numerical and machine-learning analysis of road accidents in Bangladesh using four synchronized datasets covering 2023–2025, with 288 divi-sion-month observations and a 36-month national series. The data include 17,046 acci-dents, 15,994 fatalities, and 20,389 injuries. The analysis combines singular-value and condition-number diagnostics, Normal Equation, QR, SVD and Tikhonov solvers, scaled polynomial approximation, spline and Savitzky–Golay methods, Poisson and NB2 like-lihood models, Kalman/RTS state-space estimation, Fourier analysis, and fifteen statistical and machine-learning models evaluated by leave-one-year-out validation. The fatali-ty-design matrix was full rank with κ(X)=16.73, while scaling reduced the cubic Van-dermonde condition number from 6.21×10⁴ to 7.77. Poisson was preferred to NB2 for conditional fatality analysis, and Fourier analysis identified a dominant 12-month cycle. Ridge regression, Huber regression, and Poisson random forest gave the best predictive results for accidents, fatalities, and injuries, respectively. Barishal recorded the highest annualized fatality rate at 5.44 per 100,000 population. These results show that combining numerical analysis with time-aware predictive modelling improves the robustness and interpretability of road-safety assessment in Bangladesh.

Abstract: Access to home-based smart charging may be unequal because smart capability becomes relevant only after households can obtain domestic charging infrastructure. This study examines where the disparity associated with private off-street parking arises across these two nested access stages. We used England’s 2024 National Travel Survey, the first NTS wave to observe both infrastructure stages within the same vehicle-questionnaire route. Stage 1 included all 478 eligible plug-in vehicle records with complete data; 342 records with domestic access and substantive smart-status data formed Stage 2. Survey-weighted logistic models, marginal standardization, and bootstrap inference clustered at the primary sampling unit were used to estimate and decompose the adjusted joint contrast. Private off-street parking was associated with a 41.1-percentage-point higher probability of reported smartcapable domestic charging access (95% confidence interval 27.5–51.8). Of this contrast, 40.6 points were allocated to domestic chargepoint access and 0.5 points to conditional smart status; the latter was imprecisely estimated and does not establish equivalence. The findings indicate that the observed parking disparity arises mainly before smart capability becomes relevant. Policies that expand smart functionality among existing home chargers may therefore leave the underlying domestic-access barrier unresolved. The NTS observes infrastructure states, not actual smart-charging behavior or electricity-system effects.

Abstract: Santiago's Metro network is undergoing its largest expansion since 1975 through three new lines—L7, L8, and L9—announced in two waves (2017 and 2018) and opening on staggered timelines through 2033. This multi-cohort rollout is a setting where conventional two-way fixed-effects (TWFE) designs are known to misestimate treatment effects through negative-weighting bias, while static net-present-value rules ignore the option value of deferring irreversible construction under uncertainty. We address both using a hexagon-semester panel (2010S1–2025S2; N = 67,072) and a hedonic cross-section (N = 647,849) built from Chile's SII cadastre and F2890 registry, combining Callaway and Sant'Anna's group-time estimator with a linear-programming HonestDiD sensitivity analysis and a real-options investment-timing model calibrated on the panel's own empirical volatility and drift. We find a baseline pooled hedonic capitalization elasticity of +5.9% with respect to gravity accessibility, cohort-specific dynamics a pooled TWFE obscures, a non-monotonic anticipatory uplift across socioeconomic-disadvantage quintiles, and a capitalized land-value gain 1.8 times below the real-options investment trigger—indicating anticipated capitalization alone does not yet clear the option-adjusted threshold for accelerating construction, without speaking to the corridor's broader social return. The results caution against treating land value capture as a substitute, rather than a complement, to social cost–benefit justification for transit megaprojects.

Abstract: Mobile robots with omnidirectional locomotion have attracted increasing attention owing to their superior maneuverability in confined environments. Although omnidirectional wheeled robots have been widely investigated, research on omnidirectional tracked robots remains limited. One of the key challenges in the design of such systems is the computationally efficient determination of motion resistance resulting from the rollers-surface interaction. Therefore, this study aims to develop surrogate models for predicting the longitudinal and lateral motion resistance of an omnidirectional tracked roller. A multibody dynamics model of a single roller was developed to simulate the contact interaction under different roller orientation angles, applied masses, coefficients of friction, and bearing friction torque. An experimentally validated model was subsequently employed to multiple regression surrogate models relating the operating and design parameters to the motion resistance forces. The developed surrogate models achieved coefficients of determination exceeding 99%, enabling rapid prediction of both longitudinal and lateral forces while preserving high predictive accuracy. The proposed surrogate models provide a computationally efficient alternative to repeated multibody dynamics simulations and support the design of omnidirectional tracked mobile robots.

Abstract: Bridge management systems primarily prioritize structural condition, while pavement management systems focus on roadway performance. Neither provides a unified measure of the potential for bridges to impede traffic movement by jointly considering infrastructure condition and traffic demand. This separation limits the ability of stakeholders to identify bridges where preservation investments may yield the greatest mobility benefits across a national transportation network. This study develops a mobility impedance index (MII) by integrating pavement roughness, bridge deck condition, current traffic demand, and projected traffic growth into a single composite measure. A transparent and transferrable data-integration and prioritization methodology was developed to spatially integrate the Highway Performance Monitoring System (HPMS) and National Bridge Inventory (NBI), producing a national analytical dataset of 79,595 open, unrestricted mainline NHS bridges in the contiguous United States. The index was evaluated using distributional analysis, local Getis-Ord hotspot analysis, sensitivity testing, and temporal comparability assessment. The MII exhibited a well-behaved generalized normal distribution and identified 20,621 bridges as statistically significant local hotspots, concentrated primarily within major metropolitan regions and high-demand transportation corridors. Sensitivity analyses demonstrated that the proposed MII is robust, with bridge-rank correlations ranging from 0.807 to 0.965 across the alternative specification scenarios and hotspot-set similarities ranging from 0.446 to 0.801. Restricting the analysis to bridges whose component observation years were within three years produced virtually identical prioritization results (Spearman ρ = 0.999), confirming that temporal differences among the component datasets have negligible influence on bridge rankings. The proposed MII provides transportation agencies with a nationally scalable data-driven decision-support method for network-level bridge prioritization that complements existing bridge and pavement management practices by identifying bridges and regions where preservation investments are likely to provide the greatest mobility benefits and support more sustainable allocation of limited infrastructure preservation resources.

Abstract: Transportation network disruptions can abruptly alter travel costs and trigger day-to-day route-choice adjustments. Conventional day-to-day dynamic traffic assignment models, however, often rely on fixed-weight or uniformly decaying memory structures, limiting their ability to represent traveller learning under non-stationary conditions. This study develops a Bayes with Adaptive Memory (BAM)-based framework that selectively retains, down-weights, or discounts past travel-cost experiences according to recency and statistical significance. The BAM mechanism is integrated into a link-based day-to-day traffic assignment model to examine how adaptive memory influences perceived costs, route-choice adjustment, and post-disruption traffic-flow evolution. Numerical experiments on a hypothetical network show smoother flow trajectories, faster stabilisation, and a 41.2% reduction in mean absolute perception-tracking error compared with a conventional fixed-weight model. Under a link-removal scenario, the framework captures immediate traffic redistribution followed by gradual stabilisation toward a new post-disruption state. Sensitivity analysis reveals a trade-off between responsiveness and stability: shorter memory improves cost tracking, whereas longer memory and stronger significance weighting promote smoother adjustment and earlier convergence. Within the tested setting, the results suggest that adaptive memory provides a behaviourally plausible mechanism for representing traveller learning and may support disruption-management assessments of adjustment periods, congestion redistribution, and information provision.

Abstract: Millimeter-wave radar is an attractive sensing modality for autonomous driving because of its robustness under adverse weather and lighting conditions. However, comparisons between radar object detectors are hindered by inconsistent evaluation procedures and limited reporting of deployment costs. This work presents a comprehensive benchmark using standardized VOC mean average precision (mAP) and evaluates end-to-end latency across preprocessing, network inference, and postprocessing. We evaluate SSRaDNet, a lightweight hybrid CNN–Swin Transformer detector, across analog-to-digital converter (ADC), range-Doppler (RD), and range-azimuth-Doppler (RAD) representations and compare it with existing methods on RADIal and RADDet. SSRaDNet achieves state-of-the-art AP@0.5 among re-evaluated RADIal models using RD input, reaching 88.89%, and provides the strongest overall balance of detection and segmentation performance among the compared ADC configurations. On RADDet, it achieves the best performance among methods using the native-resolution RAD tensor (45.69% mAP@0.5) and introduces the first ADC-based detector with full bounding-box regression. We also evaluate alternative postprocessing strategies, including hybrid MaxPoolNMS-GreedyNMS, to characterize deployment trade-offs on resource-constrained hardware. These results demonstrate the importance of standardized evaluation and full-pipeline runtime analysis for radar-based object detection. Code is available at https://github.com/IqbalBan/SSRadNet.

Abstract: Driving assistance and Autonomous driving are among the fastest evolving domains of intelligent transportation systems (ITSs). However, visually impaired pedestrians (VIPs), remain weakly protected by the roadsides or vehicle perception systems, especially when the right of way must be communicated in an accessible and auditable manner. In this paper we describe a safety-constrained vehicle-to-pedestrian (V2P) architecture designed for VIPs crossing assistance. The system creates a time bounded interaction state between the pedestrians, the roadside infrastructure, and the vehicles at Fog, to avoid permissive instructions before all the safety stacks are respected in each level where there are formal time bounded strictures with appropriate tools to formally abide by these rules during each interaction between vehicles and VIPs. Our objective is not to design a new detector, tracker, or MLLM model. Instead, we combine edge descriptors, fog level multi-view descriptors, and multi-camera multiple objects tracking technique (MC-MOT) within a latency-constrained V2P loop. Our main empirical focus is the WildTrack multi-camera continuity, with a novel Multi-Camera Consensus Gating (MCCG) safety primitive criterion; we also conducted a JAAD experiment as secondary assistive-branch for feasibility check, indicating plausible crossing-intent estimates, sub-second restrictive alerts, and actionable grounded guidance. On WildTrack the reproduced Fog continuity branch reaches a MOTA = 88.8%, IDF1 = 91.7%, and HOTA = 65.5%. In the WildTrack settings with N = 7, MCCG with M = 4 blocks 75% of ID-switch considering a 5.0% permissive-eligibility cost. These findings support feasibility of the proposed ITS interaction loop, while leaving field deployment of V2X stack validation, and user studies for future work.

Abstract: Car-sharing systems, as an important form of shared transport, face supply-demand imbalance and complex scheduling challenges. Heterogeneous vehicle can better meet diverse customer demands by offering vehicles with different capacities. Meanwhile, uncertainty in dispatcher movement time and vehicle relocation time may affect the reliability of scheduling plans. To address these issues, this paper focuses on a one-way station-based car-sharing problem, considering integrated scheduling, heterogeneous vehicle, uncertain dispatcher movement time and vehicle relocation time simultaneously. We define the uncertainty sets for dispatcher movement time and vehicle relocation time based on historical data from the Taxi & Limousine Commission (TLC) in Queens, New York by data-driven method. A robust optimization model is developed to improve order fulfillment and scheduling stability. We develop a hybrid approach that combines adaptive large neighborhood search and a genetic algorithm (ALNS/GA), and incorporates robustness into solution decoding and fitness evaluation under the data-driven uncertainty sets. Numerical experiments based on real TLC data show that the integrated scheduling system reduces average costs by 10.69\% compared with non-integrated systems, while the integrated robust scheduling system further improves the order fulfillment rate by 0.99\%. Sensitivity analysis also offers useful managerial insights.

Abstract: Electric vehicles (EVs) are increasingly recognised as a key component of sustainable mobility transitions. While technological advancements and supportive policies have significantly expanded EV adoption, the relatively high purchase cost of conventional EVs remains a barrier for many consumers. In response, a new generation of frugal EVs has emerged, emphasizing affordability, resource efficiency, and functional adequacy while maintaining essential mobility requirements. Despite growing commercial interest, the factors influencing the acceptance and affordability of frugal EVs remain underexplored in the academic literature. This paper addresses this gap through a structured literature review using the SALSA (Search, Appraisal, Synthesis, and Analysis) framework. A total of 116 studies were selected and analysed to identify the key factors influencing user acceptance and affordability in the context of frugal EVs. The reviewed evidence was synthesised into four principal dimensions: demographic, situational, contextual, and psychological factors. The findings indicate that affordability, low operating costs, compact urban mobility, modular vehicle design, and battery-swapping technologies are among the most important drivers of frugal EV adoption. In contrast, safety concerns, limited driving range, charging infrastructure constraints, weak resale value, regulatory uncertainty, and perceptions of lower quality remain significant barriers to market acceptance. The review further suggests that the adoption dynamics of frugal EVs differ from those of conventional EVs, particularly due to their emphasis on cost-performance trade-offs and urban mobility applications. From a smart-city perspective, frugal EVs have the potential to support more inclusive and sustainable urban transportation systems by expanding access to low-carbon mobility for cost-sensitive users and underserved market segments. The study contributes to the emerging literature on affordable electric mobility by providing a dedicated framework for understanding frugal EV acceptance and affordability. It concludes with recommendations for policymakers, manufacturers, infrastructure providers, and service operators aimed at supporting the wider adoption and distribution of frugal EVs.

Abstract: As the development of deep oil and gas resources advances continuously, the role of weighted fracturing fluids in reducing wellhead operating pressure becomes increasingly important. However, the turbulent frictional drag behaviors of weighted fracturing fluids in pipes have not been understood systematically. The frictional drag characteristics and flow behaviors of non-weighted and weighted fracturing fluids in pipes are investigated at different flow rates, densities, pipe diameters, and rheological parameters via steady-state rheological tests and pipe flow friction experiments, together with large-eddy simulation and a power-law constitutive model for generalized Newtonian fluids. Main findings are as follows. The drag reduction rates of non-weighted polyacrylamide solutions basically increase with flow rate, and the optimal molecular weight of 600–700×10⁴ corresponds to the highest drag reduction rate of 62%, while excessively large molecular weights weaken drag reduction effectiveness due to enhanced chain entanglement. The types of weighting salts have a significant effect on drag reduction performance. The 20% KCl system obtains the highest drag reduction rate of 64.8%, while the high-density CaBr₂ system gets the lowest of 42.3% because high salinity suppresses the stretching of polymers. Parameter sensitivity analysis indicates that the power-law index n is the most sensitive parameter controlling frictional drag, followed by pipe diameter D. The novelty of this study lies in integrating experimental investigation, LES, and parameter sensitivity analysis to provide a theoretical basis for deep fracturing working conditions and fracturing fluids design.

Abstract: Automatic incident detection (AID) can significantly decrease the time to detect incidents and better identify incident locations to allow faster response. The deployment of traffic surveillance cameras has motivated transportation agencies to investigate computer vi-sion technologies for AID using live video streams from these cameras. This paper evaluated three commercially available computer vision-based AID systems. The evaluated AID systems were able to use video streams from six existing Pan-Tilt-Zoom (PTZ) surveillance cameras for incident detection when these cameras were on predefined presets. The three systems with the selected settings performed differently. For example, the system with the highest number of true stopped vehicle incident detections also had a relatively high number of false alerts. The AID system accuracy also varied by study site, likely due to traffic patterns, roadway geometry, and camera angles. Two major factors contributed to false alerts: stop-and-go traffic during non-incident conditions and other highway objects, including light reflection and glare, that were falsely detected as incidents. The three systems also detected additional incidents not reported in existing incident management databases, but these were mainly shoulder incidents and work zone vehicles.

Abstract: Reliable short-term position forecasting can support collision-risk assessment, communication continuity, and prediction-assisted control in Internet of Things (IoT)-enabled unmanned aerial vehicles (UAVs). This study reformulates UAV position prediction as a flight-wise, multi-horizon, three-dimensional forecasting problem and tests whether position, velocity, gravity-resolved acceleration, and quaternion-orientation histories improve predictive accuracy while preserving edge feasibility. The dataset contains 3100 AirSim flights with high-rate kinematic, inertial, attitude, pressure, and magnetic-field measurements under variable horizontal wind. Signals are converted to a common navigation frame, gravity-resolved, low-pass filtered, resampled to 50 Hz, and partitioned by flight identifier before normalization and window construction. Each learned model receives 2 s of history and predicts the complete next 1 s trajectory, with errors evaluated at 0.1, 0.5, and 1.0 s. The sensor-enriched LSTM (LSTM-PVAQ) is compared under matched conditions with persistence, constant-velocity, constant-acceleration, extended Kalman filter, reduced-feature LSTM, GRU, temporal convolutional network (TCN), and compact Transformer baselines. LSTM-PVAQ achieved 3D RMSE values of 0.043, 0.168, and 0.371 m at 0.1, 0.5, and 1.0 s, respectively. At 1 s, its RMSE was 21.7% lower than LSTM-PV, 13.1% lower than GRU-PVAQ, 9.3% lower than TCN-PVAQ, and 16.8% lower than Transformer-PVAQ. Its one-second ADE and FDE were 0.216 and 0.339 m. On a Raspberry Pi 5 CPU using one FP32 thread and batch size one, median inference latency was 0.88 ms, well below the 20 ms model-update interval. The results show that gravity-resolved inertial and orientation histories improve multi-horizon prediction, while TCN-PVAQ remains an attractive lower-latency alternative.

Abstract: The traditional truck-based urban logistics drives the highest unit costs and externalities in urban logistics, including elevated CO₂ emissions, air pollution, road accidents, traffic congestion, road damage, and adverse social effects on delivery workers and communities. In Italy, the unique urban morphology of historic city centers, coupled with stringent Limited Traffic Zones (ZTL), make the impacts particularly severe. This paper proposes a hybrid system that exploits the existing electric regional rail network to transport freight to urban areas with fewer externalities. The system utilizes autonomous, electric wagons, such as the type built by Parallel Systems, a start-up in Los Angeles, that couple with passenger trains for suburban-to-urban transit and decouple to travel independently over dedicated short-distance connectors to urban cross-docking terminals. The study aims to improve delivery efficiency while reducing the environmental impact. A preliminary analysis for the city of Rome shows the possibility of implementing the system, and the findings indicate that Autonomous Electric Wagons (AEW) have the potential to provide a scalable and environmentally sustainable alternative for urban logistics.

Abstract: Evaluating multiple-object trackers is challenging due to the variable number of quantities involved and the mixed discrete--continuum nature of the problem. Existing methodologies primarily address detection and tracking challenges. These challenges aim at whole computer-vision pipelines as opposed to isolated tracker algorithms. However, modern tracker algorithms have become sufficiently sophisticated to merit a stand-alone analysis. The most critical component of a tracker is the association procedure, as its outcome strongly affects the overall tracking quality. We propose a straightforward quality assessment framework to evaluate the association quality of trackers. The framework relies on a minimal, query-oriented instrumentation of the tracker. This instrumentation exposes the tracker's internal association decisions, allowing for a binary classification of detection-target matches. The proposed methodology is simple to implement, introduces minimal computational overhead, and agrees with the well-known ClearMOT metrics. The comparison is implemented through our accompanying open-source software packages.

Abstract: This study presents a data-driven Digital Twin framework designed to optimize closed-loop Adaptive Cruise Control (ACC) operational parameters for eco-driving without modifying electronic control unit (ECU) firmware. High-frequency telematics data (OBD-II and GPS) were recorded from a production vehicle over an 11.57 km test corridor to engineer and calibrate a virtual Digital Twin in PTV Vissim using Wiedemann 99 car-following logic. The validated model demonstrated high empirical fidelity, achieving a mean velocity error of 2.84 km/h, a GEH statistic of 2.67, and an absolute fuel consumption variance of just 0.01 L/100 km. An iterative parametric optimization (~100 simulation runs) was executed to tune acceleration limits, convergence time constants, and target velocity bounds while maintaining strict safety constraints. The optimized Eco configuration achieved a 12% reduction in fuel consumption (4.91 to 4.33 L/100 km) alongside a 14% increase in trip duration (893 to 1019 s). Bivariate state-space analysis confirmed the complete elimination of high-intensity accelerations and a 0.48 percentage point reduction in hard braking. The framework serves as an algorithmic decision support tool for energy-aware fleet management and adaptive vehicle control.

Abstract: In recent years, increasing attention has been devoted to improving cyclists’ safety in road traffic, particularly on roads without separated cycling infrastructure. Advisory cycle lanes (2–1 roads) have recently been introduced in several European countries on narrow roads where conventional cycling facilities cannot be provided. However, evidence regarding their safety effects remains limited. This paper evaluates the effects of advisory cycle lanes on overtaking behaviour and crash occurrence on selected roads in and around Maribor, Slovenia. The study combines OpenBikeSensor measurements of lateral passing distance, traffic volume and speed data, and a before-and-after analysis of police-reported crashes. In total, 970 overtaking manoeuvres were recorded on six streets with advisory lanes and comparable control streets without cycling infrastructure. Advisory bike lanes were associated with greater lateral passing distances, with mean clearance increasing from 135 cm to 156 cm. Nevertheless, around 40–50% of overtakes still occurred within 1.5 m of the cyclist. Crash analysis indicated reductions of about 22% in total crashes and 38% in cyclist-involved crashes, although the small number of crashes warrants cautious interpretation. The collected data enable a comparison of traffic behaviour and safety effects of advisory cycle lanes in Slovenia, providing a basis for future planning of traffic infrastructure aimed at improving the coexistence of cyclists and motor vehicle drivers.

Abstract: Road traffic accident remains a major public-health and transportation challenge in Bangladesh, while existing studies often rely on isolated datasets, random validation, point predictions, and descriptive rankings that do not distinguish absolute burden from exposure-adjusted risk. This study develops an integrated, leakage-safe, uncertainty-aware, and policy-oriented framework using four nationwide datasets covering population characteristics, accidents, fatalities, injuries, vehicle involvement, and vehicle-specific fatalities across eight administrative divisions from January 2023 to December 2025. Linked division–month and vehicle–division–month panels were constructed with population-normalized indicators, cyclical seasonality, lagged dynamics, rolling variability, and momentum features. Mean and seasonal-naïve baselines, Ridge, Poisson, Tweedie, Random Forest, Extra Trees, Gradient Boosting, Histogram Gradient Boosting, and a hurdle model were evaluated using expanding-window validation and an independent 2025 holdout year. The framework further incorporated empirical-Bayes vehicle-risk stabilization, split-conformal prediction intervals, permutation importance, feature-family ablation, spatial concentration, hotspot persistence, and a transparent policy-priority index. National fatalities remained persistently high, while exposure-adjusted analysis identified Barishal and Sylhet as emerging-risk divisions despite the larger absolute burden in Dhaka and Chattogram. Motorcycles recorded the highest stabilized fatality risk, followed by auto rickshaws and other lightly protected vehicle categories. Random Forest achieved the lowest holdout fatality RMSE of 15.77, outperforming the seasonal-naïve benchmark by 26.7%, although count and regularized models remained competitive. Ablation analysis showed that the temporal-plus-demographic specification generalized better than the fully integrated feature set. The study contributes a reproducible decision-support architecture for seasonal enforcement, vehicle regulation, emergency-response allocation, infrastructure prioritization, and divisional monitoring. Prospective validation remains necessary before full operational deployment.