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Research Article
Lime Stabilization Effects on Geomechanical Properties of Kombe Mbanga Soils Road Subgrade (Cameroon)
Guimezap Kenou Willy Chance*
,
Nie Noumsi Thierry Constant,
Taypondou Darman Japhet,
Asmaou Daoua Youssoufa Yasmine
Issue:
Volume 12, Issue 3, September 2026
Pages:
84-97
Received:
13 June 2026
Accepted:
1 July 2026
Published:
24 July 2026
Abstract: Road infrastructure in Cameroon experiences rapid deterioration due to intense seasonal rainfall, high temperatures, and the predominance of weak lateritic soils in tropical environments. These unfavorable conditions reduce pavement performance, increase maintenance costs, and hinder sustainable transportation development, particularly on rural road networks. Soil stabilization using locally available materials has emerged as a cost-effective strategy for improving the engineering properties of these problematic soils. This study evaluates the effectiveness of locally sourced quicklime in enhancing the geotechnical characteristics of lateritic soils collected from the Kombe-Mbanga area in Cameroon and assesses its suitability for road subgrade applications. Ten representative soil samples were collected and characterized through laboratory testing, including particle size distribution, Atterberg limits, Modified Proctor compaction, California Bearing Ratio (CBR), and direct shear strength tests. The tests were performed before and after quicklime stabilization to quantify changes in the soils' mechanical behavior. In addition, statistical analyses were conducted to investigate the relationships between key geotechnical parameters and bearing capacity. The results demonstrate substantial improvements following stabilization. The average CBR increased from 9.04 to 45.08, indicating a significant enhancement in load-bearing capacity. Cohesion increased from 27 to 57 kPa, while the internal friction angle improved from 30° to 57°, reflecting greater shear strength and stability. Statistical analysis further revealed a strong negative correlation between the plasticity index and CBR (r = −0.67), confirming that high plasticity and fine particle content are the primary factors responsible for the poor engineering performance of the untreated soils. These findings demonstrate that locally available quicklime provides a simple, economical, and effective stabilization technique capable of transforming weak tropical lateritic soils into suitable road subgrade materials. The study offers practical guidance for the rehabilitation and construction of durable rural roads in Cameroon and other tropical regions with similar geotechnical and climatic conditions.
Abstract: Road infrastructure in Cameroon experiences rapid deterioration due to intense seasonal rainfall, high temperatures, and the predominance of weak lateritic soils in tropical environments. These unfavorable conditions reduce pavement performance, increase maintenance costs, and hinder sustainable transportation development, particularly on rural roa...
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Research Article
Mathematical Modeling for Road Accident Analysis in Bangladesh: Nonlinear Deterministic, Exposure-Adjusted Count, and Seasonal Time-Series Approaches
Sree Pradip Kumer Sarker*,
Md. Shahid Mamun
Issue:
Volume 12, Issue 3, September 2026
Pages:
98-118
Received:
26 July 2026
Accepted:
8 August 2026
Published:
24 August 2026
Abstract: This study establishes a coherent mathematical model for the investigation of road accidents in Bangladesh by integrating nonlinear deterministic modeling, count regression with exposure, normalized fatality-rate estimation and seasonal time-series forecasting. The analysis constructs a balanced monthly panel from January 2023 to December 2025, with 36 national monthly observations and 288 division-month observations, using four synchronized datasets on population, monthly accidents, fatalities by type of vehicle, and vehicle involvement. During the study period, Bangladesh recorded 17,046 accidents, 15,994 deaths, 20,389 injuries and 36,383 total casualties indicating a persistently high and fluctuating national toll. Analysis of the deterministic model shows that harmonic quadratic equations best describe the accidents and fatalities, a harmonic linear equation the injuries, and a cubic equation the accident severity index, confirming the absence of any single common trend structure across the burden dimensions. Seasonal-index analysis revealed that June is the month with the highest number of accidents, fatalities and injuries, while August is the lowest month for accidents and fatalities and November for injuries, indicating consistent annual patterns. At the division-month level, the negative binomial model is significantly better than the Poisson model, reducing the AIC by 275.558 points, indicating significant overdispersion in accident occurrences. The harmonic OLS model for the fatality rate accounts for 46.1% of the variation in fatalities per 100,000 individuals. The SARIMAX forecast has a 12-month seasonal memory and projects a rise in June 2026 and a fall in August 2026. The results suggest that the incidence of road accidents in Bangladesh is influenced by nonlinear trends, seasonal variations, exposure disparities, and random temporal correlations, providing a mathematically coherent basis for risk assessment and road safety strategies.
Abstract: This study establishes a coherent mathematical model for the investigation of road accidents in Bangladesh by integrating nonlinear deterministic modeling, count regression with exposure, normalized fatality-rate estimation and seasonal time-series forecasting. The analysis constructs a balanced monthly panel from January 2023 to December 2025, wit...
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Research Article
Dalton Traffic Light: Equal and Indivisible Safety for All Road Users
Yuriy Kozin*
Issue:
Volume 12, Issue 3, September 2026
Pages:
119-124
Received:
7 July 2026
Accepted:
27 July 2026
Published:
18 September 2026
DOI:
10.11648/j.ijtet.20261203.13
Downloads:
Views:
Abstract: For the first time, a theoretically based combination of colour and shape of traffic light signals is proposed. As a result of this combination, a new effective traffic light model (Dalton Traffic Light) is created. The purpose of the Dalton Traffic Light is to ensure equal and indivisible safety and new conveniences for all road users; to radically improve road safety and the quality of life of people with color vision deficiency (CVD, color blindness) and other visual impairments. A person receives information mainly visually, therefore; despite the active introduction of digital intelligent technologies, traffic lights, like road signs, is the most important means of visualising the rules for organising and ordering traffic flow. The traditional traffic light does not provide identical control signals universally to all road users. A significant portion of conventional traffic light users are discriminatorily limited in the quality (unambiguity) of the control signals. Identical round traffic light signals cannot be combined to create a universal combined traffic light section. Compared with the existing traditional design, the Dalton traffic light has the following social, information, economic and aesthetic advantages: the most important benefit from a social perspective is the rehabilitation of a large group of people as equal road users (Restrictions on issuing driver's licenses may be lifted too). “Arrow” (apex) of the yellow intermediate triangular signal indicates in advance which signal (green or red) will be activated next. This clear additional information improves decision-making accuracy and contributes to improved road safety. Reduction of material, energy, transport and service costs for the manufacturing and operation of universal combined traffic light sections (one-section and two-section) compared to conventional traffic lights. Compact Dalton Traffic Lights (one-section and two-section) help reduce visual pollution of the street and road network. There are important anti-conservative aspects of the device implementation: the Dalton Traffic Light (vertical or horizontal) does not require changes to the colour, position or signal sequence of existing traditional traffic lights. The functions of the additional green arrows and red, yellow and green arrows of the standard traffic light remain unchanged. For the Dalton Traffic Light, the current rules and technical regulations (operating mode: steps, phases and control cycles; duration of the control phase; operating conditions: installation rules, elements of the supporting structure, reliability of fastening, etc.) are applied, which are observed during the operation of a conventional traffic light.
Abstract: For the first time, a theoretically based combination of colour and shape of traffic light signals is proposed. As a result of this combination, a new effective traffic light model (Dalton Traffic Light) is created. The purpose of the Dalton Traffic Light is to ensure equal and indivisible safety and new conveniences for all road users; to radicall...
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