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Time lost by driving fast in the United States
Donald A Redelmeier1, Ahmed M Bayoumi
1Department of Medicine, University of Toronto, Toronto, Ontario, Canada, Department of Health Policy, Management, & Evaluation University of Toronto, Toronto, Ontario, Canada. dar@ices.on.ca
Summary
Slightly reducing average driving speed in the United States can significantly decrease total lost time and improve public health. Lowering speeds by 3.0 km/h minimizes time lost, saving lives and reducing crashes.
Area of Science:
- Public Health
- Transportation Safety
- Traffic Engineering
Background:
- Drivers balance travel time savings against crash risks.
- Decisions on driving speed involve trade-offs between efficiency and safety.
Purpose of the Study:
- To analyze the public health impact of average driver speed in the U.S.
- To determine optimal driving speeds for minimizing overall time lost.
Main Methods:
- Computerized modeling using national data.
- Calculation of time lost from both travel and crashes.
- Analysis of speed changes on public health outcomes.
Main Results:
- A 1-km/h speed increase raises expected lost time due to higher crash probability.
- A 3.0-km/h speed decrease minimizes total time lost.
- Lowering average speed by 3.0 km/h reduces daily crashes by ~11,000 and conserves ~199 life years annually.
Conclusions:
- U.S. drivers currently travel slightly too fast.
- A modest reduction in average driving speed can enhance national life expectancy.
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