Abstract:
Overall traffic delay model for estimating the mean and variance at a signalized
intersection is discussed. The model was developed under basis of two delay
components, namely deterministic and stochastic components. The latter component
was put under D/D/1 framework and therein mean and its variance derived. While the
stochastic component was put under the M/G/1 framework, mean and variance derived.
Extension on stochastic component and M/G/1 framework was discussed with the usage
of compressed queueing processes. Harmonization of the moments of deterministic and
stochastic components to obtain the overall central moments of traffic delay has been
discussed. Illustration of the model on real traffic data has been carried out. Simulation
was performed using statistical software for traffic intensities ranging from 0.1 to 1.9.
The simulated results indicate that both deterministic and stochastic components are
incompatible as the traffic intensity approaches capacity. Also, the simulation shows
that variance of overall traffic delay drops linearly when the traffic intensity is less than
3 because of increasing rate of random arrivals. This variance decreases slowly as the
traffic intensity approaches capacity and slowly increases as the traffic intensity goes
beyond capacity. This confirms the results that exist in literature that oversaturated
conditions and random delay renders the stochastic component in traffic delay models
unrealistic.
