# The relationship between income level and road traffic deaths: an empirical analysis for 22 OECD countries

## TL;DR

This study finds a nonlinear relationship between income levels and road traffic deaths in OECD countries, suggesting higher income initially increases deaths but eventually reduces them.

## Contribution

The novel contribution is identifying an inverted U-shaped relationship between income and road traffic deaths in OECD countries using advanced regression models.

## Key findings

- There is an inverted U-shaped nonlinear relationship between road accident deaths and per capita income.
- Higher health expenditures reduce traffic accident deaths, while increased alcohol consumption raises them.
- 21 OECD countries converge to the OECD average in traffic accident deaths, but 13 do not.

## Abstract

The increase in transportation and travel demands leads to the development of social welfare, and on the other hand, it may adversely affect socio-economic indicators such as death, injury, air pollution and budget deficit. Every day, thousands of people are killed, injured, or disabled due to road accidents around the world. The high cost of fatal and non-fatal road accidents to national economies is important in terms of policies to be implemented. This study aims to examine the relationship between road accidents and income levels in 22 OECD countries.

Poisson Regression, Negative Binomial, and Quantile Regression Fixed Effect were used in models estimation. In addition, the convergence of traffic accident deaths for 34 OECD countries was investigated. Fractional frequency unit root test with structural break was used for convergence analysis.

The findings of the study show that there is an inverted U-shaped nonlinear relationship between road accident deaths and per capita income. In addition, while the increase in health expenditures reduces the number of deaths due to traffic accidents, the increase in alcohol consumption increases these deaths. The results obtained from the convergence analysis indicates that 21 OECD countries converge to the OECD average, but 13 countries do not converge.

Infrastructure investments for road safety such as traffic lights, curves, wide highways should be effectively implemented by the public. Pedestrians or drivers who put road safety at risk should be given deterrent penalties when necessary. In addition, public awareness should be increased regarding traffic rules and life safety.

Not applicable.

The online version contains supplementary material available at 10.1186/s12889-025-23726-9.