One of the challenges of urbanizing African cities in terms of mobility is traffic
congestion. Congestion, long queues, and unpredictable travel times in Calabar,
Nigeria, are a daily experience, especially in commercial areas and along major
roads. In this study, congestion states are predicted using Gaussian Process
Regression (GPR) and a Relevance Vector Machine (RVM), based on field data
from 20 large corridors. The findings indicate considerable variation in congestion
rates across places. Post hoc Tukey HSD tests indicate that congestion is
intermittent and is instigated by localized pinpoints of congestion at the Harbor,
Tinapa, Main Avenue, Goldie, and Ettagbor crossings. Ekpo Abasi, Uwanse, and
Goldie, on the other hand, were doing fairly well regarding delay and queue
length. Vehicle arrivals were the most important feature, with the strongest linear
correlations with total delay (r = 0.669) and queue length (r = 0.858), and traffic
demand showed a positive linear association with the volume-to-capacity ratio (r
= 0.568). GPR was more effective than RVM in all the congestion indicators. GPR
obtained R² values of 0.876 (total delay), 0.966 (queue length), and 0.735 (VCR) on
the test set with well-calibrated 95% credible interval coverage (94.1%, 93.0%,
90.2%). The locations of congestion were detected as clusters in the spatial maps
around markets, schools, and transport termini. These findings support
congestion hotspot-specific interventions and endorse probabilistic modeling,
particularly GPR, for traffic prediction in data-sparse African cities. This study
provides evidence-based recommendations for transportation policy, route
planning, and signal optimization in Calabar.
Keywords: Calabar, Gaussian, Learning, Machine, Regression, Relevance, Traffic,
Vector
