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
DOI:
10.11648/j.ajtte.20261105.12
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Views:
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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