Summary of Economic Valuation of Traffic Accidents

## Introduction Traffic accidents generate losses beyond immediate medical and repair bills: they create externalities—costs imposed on victims, families, insurers, employers, and society. This study material explains how economists measure those costs, the main valuation methods, key results from a Czech case study, and practical implications for policy and transport planning. > **Definition:** Externalities caused by traffic accidents are negative effects (health, financial, psychological, social) borne by individuals or society that are not fully reflected in market transactions. ## Why value traffic-accident externalities? - To prioritise safety investments and policies using cost-benefit analysis. - To compare road safety performance across regions and over time. - To set insurance premiums and estimate socio-economic burdens. ## Core valuation concepts ### Restitution (direct) costs - Costs with clear market prices incurred to restore the pre-crash state. Examples: - Medical treatment, ambulance, hospital stays - Property damage and vehicle repair - Police, fire, rescue service salaries and operations - Restitution costs are typically estimated from administrative and insurance data. > **Definition:** The restitution cost method estimates the monetary value of goods and services consumed or replaced due to an accident. ### Human capital approach - Values lost productivity due to temporary or permanent incapacity or premature death. - Calculated as discounted future earnings lost because of death or disability. > **Definition:** The human capital approach converts lost or reduced labour-market output from injury or death into monetary terms using expected earnings. ### Willingness to pay (WTP) - Measures how much individuals would pay to reduce their risk of death or serious injury. - Captures intangible human costs: value of life years, pain, and reduced quality of life. - Often estimated with stated preference surveys (choice experiments) or revealed preference methods. > **Definition:** Willingness to pay is the amount individuals are prepared to pay for a marginal reduction in mortality or morbidity risk. Fun fact: Willingness-to-pay studies often produce higher monetary values for life (VSL) than those implied by the human capital method because they capture pain, suffering, and subjective values, not just lost earnings. ## Measuring values: VSL and IFSSI - **Value of a Statistical Life (VSL):** the aggregate amount a population would pay to reduce the expected number of deaths by one. Example from the Czech study: VSL = $1.81\ \text{million}\ \mathrm{EUR}$ (2021 estimate). - **Value of a Statistical Serious Injury (IFSSI):** the monetary value assigned to preventing a serious injury. Example: IFSSI = $0.35\ \text{million}\ \mathrm{EUR}$. ### How stated preference surveys produce VSL - Respondents choose between policy options that differ by cost to them and number of deaths/injuries prevented. - A multinomial model for panel data estimates the trade-off between cost and risk reduction, yielding VSL and IFSSI. - Example parameters: Czech survey with 0.051 respondents aged 10+ (stated preference choice experiment, 16 binary trials per respondent). ## Data sources and limitations - Typical data sources: - National statistics and administrative records (e.g., Czech Statistical Office) - Insurance databases (e.g., Czech Insurers' Bureau) - Special surveys (stated preference) and expert estimates - Common limitations: - Underreporting of minor injuries or single-person non-motor-vehicle accidents - Differences in definitions and methods across countries limit comparability - Scenario framing and respondent experience can bias stated preference answers Did you know that underreporting is most common for minor injuries occurring outside motor-vehicle collisions, which can lead to underestimation of total socio-economic costs? ## Practical examples and applications - National cost estimation: