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Research Article
Geotechnical Evaluation of Traffic-induced Load effects on Pavement Sub-Grade Bearing Capacity Along the
Okene–Auchi Highway, Nigeria
Ogum Prosper Chukwunweike,
Wasiu John,
Ibrahim Abdulrazaq Olayinka*
,
Igbadumhe Anthony Oshioke,
Haruna Daud Gussau
Issue:
Volume 11, Issue 5, October 2026
Pages:
82-90
Received:
20 April 2026
Accepted:
8 August 2026
Published:
2 September 2026
Abstract: This study investigates the effects of heavy traffic loading on subgrade bearing capacity using field and laboratory data obtained from Jattu Junction along the Okene–Auchi Highway, Nigeria. Manual traffic count data were converted into Equivalent Single Axle Loads (ESAL), resulting in an Index Daily Traffic (IDT) of 7,985 ESAL/day and a corresponding daily axle mass of 2,984.86 tonnes. Heavy vehicles, including trucks and trailers, account for over 95% of the total traffic loading, imposing substantial stresses on the pavement subgrade. Geotechnical laboratory tests revealed specific gravity values ranging from 2.46 to 2.49, liquid limits of 11–35%, plasticity indices of 5–12%, maximum dry density (MDD) values of 1.81–1.95 Mg/m³, optimum moisture content (OMC) of 10.2–11.8%, and soaked California Bearing Ratio (CBR) values between 5% and 45%. The results indicate that more than half of the sampled soils fail to satisfy the minimum soaked CBR requirement of 30% specified for subgrade design, demonstrating inadequate load-bearing capacity under prevailing traffic conditions. The study establishes a strong relationship between heavy traffic loading, moisture susceptibility, and reduced subgrade strength, all of which accelerate pavement deterioration through rutting, deformation, and premature failure. These findings highlight the importance of integrating traffic loading characteristics with geotechnical properties during pavement design and maintenance planning. To enhance pavement durability and long-term service performance, the study recommends appropriate subgrade stabilization techniques, strict enforcement of axle load regulations, and improved drainage systems to minimize moisture-induced weakening of the subgrade.
Abstract: This study investigates the effects of heavy traffic loading on subgrade bearing capacity using field and laboratory data obtained from Jattu Junction along the Okene–Auchi Highway, Nigeria. Manual traffic count data were converted into Equivalent Single Axle Loads (ESAL), resulting in an Index Daily Traffic (IDT) of 7,985 ESAL/day and a correspond...
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Research Article
Temporal Dynamics and Statistical Modelling of Road Crash Frequency, Severity Composition, and Vehicle Involvement in Dhaka City of Bangladesh
Md Arif Azad,
Sree Pradip Kumer Sarker*,
Md Shahid Mamun
Issue:
Volume 11, Issue 5, October 2026
Pages:
91-109
Received:
13 August 2026
Accepted:
25 August 2026
Published:
15 September 2026
Abstract: Dhaka's road-safety burden is shaped not only by the number of reported crashes but also by changes in severity, pedestrian involvement, and the number of vehicles participating in each event. This study develops an internally validated annual time series from road-accident, casualty, and vehicle cross-tabulations for Dhaka City for 1998-2015, supplied as data from the Accident Research Institute (ARI), Bangladesh University of Engineering and Technology (BUET). The harmonised record contains 10,959 reported crashes, 12,470 casualty records, and 15,697 involved-vehicle records. Data quality was assessed by reconciling independent table totals and reconstructing crash counts from the vehicle-distribution table. Temporal behaviour was evaluated using descriptive statistics, ordinary least squares with HC3 robust standard errors, Mann-Kendall and Theil-Sen trend estimators, Poisson and negative binomial NB2 count models, grouped binomial logistic models, segmented regression, Spearman correlation, and principal component analysis (PCA). Reported crashes decreased from 1,202 in 1998 to 391 in 2015 (-67.5%), casualty records decreased by 65.2%, and involved-vehicle records decreased by 73.8%. Strong Poisson overdispersion (8.22-27.06) favoured NB2 models; the crash-frequency NB2 incidence-rate ratio was 0.525 per decade (95% CI: 0.459-0.602). However, the fatal-crash share rose from 33.2% to 74.2% (grouped-binomial OR = 3.044 per decade), the pedestrian casualty share rose from 35.9% to 59.4%, and the pedestrian-collision share rose from 41.0% to 71.4%. Conversely, the multi-vehicle crash share fell from 52.8% to 23.8%, and mean vehicles per crash declined from 1.562 to 1.256. The first two principal components explained 84.2% of standardised annual variation. Overall, the findings indicate a transition from a higher-frequency, multi-vehicle crash profile toward a lower-frequency but more fatal- and pedestrian-concentrated reported crash structure. These results support prioritising pedestrian protection, speed management, safer junctions and public-transport interfaces, and stronger integrated crash-data systems in Dhaka. Because exposure denominators and crash-level covariates were unavailable, the results should be interpreted as temporal associations in reported events rather than causal or exposure-adjusted risk estimates.
Abstract: Dhaka's road-safety burden is shaped not only by the number of reported crashes but also by changes in severity, pedestrian involvement, and the number of vehicles participating in each event. This study develops an internally validated annual time series from road-accident, casualty, and vehicle cross-tabulations for Dhaka City for 1998-2015, supp...
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Research Article
Comparative Benchmarking of YOLOv8 Variants for Traffic Sign Detection
Nnanna Ekedebe*
Issue:
Volume 11, Issue 5, October 2026
Pages:
110-116
Received:
13 July 2026
Accepted:
24 July 2026
Published:
18 September 2026
Abstract: Road traffic accidents remain a leading cause of injury and death worldwide, and driver failure to correctly identify traffic signs is a significant contributing factor. Many devastating and deadly road traffic incidents are directly linked to poor sign recognition, particularly in Nigerian and developing-region road conditions, where faded signage, poor lighting, and occlusion are common conditions poorly served by existing standardized-signage-focused research. Most existing work is either classification-only on pre-cropped signs, such as NaijaTrafficNet, or detection-based but not comparatively benchmarked for resource-constrained deployment relevant to this context. This study aims to determine which YOLOv8 variant offers the best accuracy-speed-size tradeoff for real-time detection under resource-constrained conditions relevant to developing-region deployment. This study addresses this gap by comparatively benchmarking three YOLOv8 variants — nano, small, and medium on an 11-class filtered traffic sign detection dataset, comprising 800 training, 223 validation, and 79 held-out test images, evaluated on precision, recall, mAP@0.5, mAP@0.5:0.95, FPS, and model size on a held-out test set. All variants performed closely within a narrow accuracy band, with YOLOv8n matching or exceeding the larger variants in accuracy while offering the smallest footprint and highest inference speed, showing that higher model capacity does not improve generalization at this dataset scale. YOLOv8n achieved the highest test-set mAP@0.5 of 0.897 at only 3.0M parameters and 6.2MB, versus YOLOv8m's 0.886 at 25.8M parameters and 52.0MB — despite YOLOv8m ranking highest on validation, underscoring the importance of held-out test evaluation. YOLOv8n is therefore recommended as the most viable variant for real-time, resource-constrained deployment on dashcams or roadside cameras in developing-region contexts, pending real-world Nigerian and embedded-hardware validation.
Abstract: Road traffic accidents remain a leading cause of injury and death worldwide, and driver failure to correctly identify traffic signs is a significant contributing factor. Many devastating and deadly road traffic incidents are directly linked to poor sign recognition, particularly in Nigerian and developing-region road conditions, where faded signage...
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Research Article
Assessment of Road Safety in Relation to Public Transport Driver Behavior in Addis Ababa, Ethiopia
Zebider Nega*
Issue:
Volume 11, Issue 5, October 2026
Pages:
117-123
Received:
3 August 2026
Accepted:
4 October 2026
Published:
28 October 2026
Abstract: Road traffic accidents (RTAs) present critical socio-economic, environmental, and public health challenges in developing urban regions. Global crash metrics attribute over 90% of traffic collisions in low- and middle-income nations to human error and driver behavioral patterns. In Addis Ababa, Ethiopia, public transit relies heavily on minibus taxis and city buses. Official crash metrics attribute 86% to 90% of traffic collisions in the city to driver errors and aberrant behavioral patterns. This study assesses road safety practices in relation to public transport driver behaviors in Addis Ababa using primary survey data (N=45) alongside 16-year historical crash trends (2002–2017). Statistical procedures—including K-Means Cluster Analysis, ANOVA, Pearson Correlation, and cross-tabulations—were executed via IBM SPSS Statistics. K-Means clustering established three distinct driver risk profiles: Young Novices (60.0%), Mid-Career Drivers (37.8%), and Senior Outliers (2.2%). Age (F=66.64, p<0.001) and driving experience (F=71.44, p<0.001) proved to be statistically significant predictors partitioning driver risk profiles. Younger drivers exhibited higher exposure to occupational fatigue (8+ driving hours daily), vehicle rental financial pressures, lower seatbelt compliance, and aggressive maneuvers.
Abstract: Road traffic accidents (RTAs) present critical socio-economic, environmental, and public health challenges in developing urban regions. Global crash metrics attribute over 90% of traffic collisions in low- and middle-income nations to human error and driver behavioral patterns. In Addis Ababa, Ethiopia, public transit relies heavily on minibus taxi...
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Research Article
Headway Instability, Uneven Bus Loading and Fuel Use on an Urban Bus Route: A Simulation Study of Route No. 2 in Namangan, Uzbekistan
Ulugbek Mamirov Xabibulayevich*
Issue:
Volume 11, Issue 5, October 2026
Pages:
124-131
Received:
9 October 2026
Accepted:
20 October 2026
Published:
31 October 2026
DOI:
10.11648/j.ajtte.20261105.15
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Abstract: Bus bunching is usually treated as a service-quality problem: passengers wait longer and crowd into the first of two buses that arrive together. This paper argues that it is also a vehicle-operation problem, because irregular headways translate directly into irregular bus mass, dwell time and fuel use. The argument is tested on route No. 2 "Chorsu – Otchopar" in Namangan, Uzbekistan, a 14.6 km central route served by twelve 70-passenger buses and carrying about 8,240 passengers per day. Segment lengths and running times from the route passport show technical speeds ranging from 4 to 45 km/h; five short segments near markets and junctions take up 9% of the route length but 24% of the running time. A stochastic multi-bus simulation of the morning peak was built on these data, with stop dwell times linked to boarding and alighting, lognormal running-time noise and no overtaking. Four operating regimes were compared over 30 replications each: the current schedule-based service with a 12-min headway, holding at four control stops, transit signal priority (TSP) on the congested segments, and an integrated regime that combines a 9-min headway, holding, TSP and faster card payment. Under the current regime the headway coefficient of variation grows along the route from 0.11 to 0.52, which confirms the self-reinforcing nature of delays. Holding alone stabilised headways (coefficient of variation 0.24) but lengthened the trip by 2.4 min and slightly raised fuel use. TSP shortened the trip by 9.4% but left headways irregular. The integrated regime cut the mean passenger wait from 6.8 to 4.7 min, reduced trips reaching full capacity from 3.3% to 0.2% and lowered estimated diesel consumption by about 10%, while the spread of fuel use between trips narrowed by a factor of 2.3. The results suggest that headway control and signal priority should be planned together, and that their benefits for the operator are understated when only passenger waiting time is counted. The study is model-based; field validation with automatic vehicle location and fuel records is the next step.
Abstract: Bus bunching is usually treated as a service-quality problem: passengers wait longer and crowd into the first of two buses that arrive together. This paper argues that it is also a vehicle-operation problem, because irregular headways translate directly into irregular bus mass, dwell time and fuel use. The argument is tested on route No. 2 "Chorsu ...
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