DST

Abstract

• Analysis of daylight saving time (DST) effects on road safety.

• Estimate long-term consequences of time regimes based on light conditions.

• Annual costs of darkness exceed £500 million in Great Britain. 8% in savings possible with year-round DST.

I. Introduction

• Daylight Saving Time (DST): Clocks moved forward in spring and back in autumn, introduced to conserve energy by extending daylight.

• Current Adoption: Around 70 countries employ DST, covering ~25% of the global population.

• Legislation Efforts: March 2019 saw the introduction of the Sunshine Protection Act in the U.S. Congress and European Parliament's vote to abolish clock changes from 2021.

• Concerns Raised: Debate whether DST harms outweigh benefits; some studies suggest DST increases overall energy consumption.

• Health Impacts: Transitions in DST can disrupt circadian rhythms, affecting sleep and contributing to various adverse health outcomes (e.g. increased accidents, higher risk of heart issues, etc.).

II. Empirical Framework

A. Data and Measurement

• Data Source: STATS19 database from UK Department for Transport (1996-2017).

• Data Properties: Comprehensive accident details, regional coverage, reliable data collection methods (~80% police attended).

• Accident Categories: Includes various demographics and severities.

• Weather Data: Included from MIDAS to account for external conditions affecting road safety.

B. Identification and Estimation

• Use variation in darkness from sunrise/sunset timings to estimate road safety impacts.

• Regressions: Estimate log counts of accidents against darkness; focus on causal relationships.

III. Results

A. Main Results

• Impact of Darkness: Each hour of darkness leads to a 7% increase in accidents; fatalities increase by 31.8% in dark conditions.

• Simulation Findings: Year-round DST could prevent at least £40 million of accident-related costs.

B. Mechanisms

• Discussed is the influence of darkness on visibility, driver concentration, and the effects on specific demographics such as older drivers and pedestrians.

C. Sensitivity Analyses

• Various aggregation schemes were used; results consistent across different measures of darkness.

IV. Conclusion

• Policy Implications: Establishing year-round DST has potential to significantly reduce road casualties and monetary costs.

• Recommendation: Year-round DST should be considered to improve road safety and public health outcomes.