Estimating the total number of vehicles active on the road in Saudi Arabia

الملخص EN

Knowledge of the total number of vehicles active on the road (TNVAR) is an important input in planning and managing road transportation system.

Such figure is not available in the Kingdom of Saudi Arabia.

This paper presents a modelingbased methodology to estimate TNVAR.

The model is composed of three sub-models that estimate the number of vehicles leaving service due to re-export, accidents, or retirement by wear and tear, respectively.

It uses as its inputs available annual vehicle registration, export, and accident statistics.

Three different decay functions were considered for the retirement sub-model: power, exponential and logit.

The model was calibrated using the 1403H TNVAR, when all vehicles were asked to re-register, and the 1410H vehicle age mix data obtained from Motor Vehicle Inspection Program (MVIP).

Results show that the power decay function gives the best fit of the data, and that the average vehicle life is 11 year.

The calibrated model was then applied to regenerate the TNVAR for the period 1403-1419H.

The modelpredicted 1419H TNVAR, about 1.8 million, was used to validate the model, by comparing it with the corresponding actual figure, obtained from the new alpha-numerical license plate re-issue statistics.

The paper demonstrates two applications of the calibrated and validated model: 1403-1419H historical trends of accidents, injuries and fatalities rates, per 1000 vehicles, and that of vehicle ownership rate per capita.