Forecasting of automobile sales amount by fuel type and determination of fuel price pass-through in Turkey

The automotive sector in the world and in Turkey is constantly developing and automobile sales are increasing accordingly. New types of vehicles have emerged in the sector due to technological developments. Especially due to the interest in electric vehicles, sales of electric vehicles have increased significantly in recent years. The aim of this study is to make forward-looking estimates of sales figures of internal combustion (gasoline, diesel and LPG) and electric vehicles (fully electric and hybrid electric) in Turkey and to determine the transitivity between fuel prices (gasoline, diesel, LPG and electricity), in other words, to determine whether there is an interaction between them. For these purposes, ARIMA, one of the time series analysis methods, was used to make estimates of automobile sales by fuel type from October 2024 to December 2025 using monthly data between January 2019 and September 2024. In addition, the Johansen Cointegration Test was applied to determine the existence of a long-term relationship between fuel prices and monthly data between January 2016 and September 2024. The causality relationship between fuel prices was tested with the Vector Error Correction Model (VECM) and Granger Causality Test. Vehicle sales estimates for the next 15 months obtained in the study show that gasoline vehicle sales generally tend to decrease. On the other hand, an increase is expected in the sales of diesel and LPG vehicles. On the other hand, significant increases and decreases were observed in the sales of fully electric and hybrid vehicles. The Johansen Cointegration Test results show that there is a cointegration relationship between gasoline, diesel, LPG and electric fuel prices and that there is a long-term relationship. The Vector Error Correction Model (VECM) findings also show that fuel type prices have a long-term effect on each other. The Granger Causality Test results show that there is a certain level of causality between fuel type prices.