A combined stability function to quantify flood risks to pedestrians and vehicle occupants

Area of Science:

• Environmental Science
• Urban Hydrology
• Risk Assessment

Background:

• Increasing frequency and severity of flooding events due to climate change and urbanization.
• Growing population density in urban areas exacerbates flood risks.
• Limited understanding of simultaneous risks to vehicle occupants and pedestrians during urban floods.

Purpose of the Study:

• To propose a methodology for assessing flood risks to both vehicle occupants and pedestrians in urban environments.
• To derive a risk assessment profile for vehicle occupants based on vehicle stability.
• To analyze potential risks during historical and synthetic rainfall flood events.

Main Methods:

• Development of a risk assessment methodology considering vehicle stability functions for various vehicle types.
• Analysis of a historical 1-in-20-year flood event in Exeter, UK (2014).
• Simulation of a synthetic 1-in-100-year rainfall flood event.

Main Results:

• For analyzed flood events, remaining in a vehicle is riskier than exiting.
• Immobilized vehicles in floodwaters present a rapidly increasing risk within approximately 10 minutes.
• Risk levels escalate significantly if individuals stay within an immobilized vehicle awaiting rescue.

Conclusions:

• The study highlights the critical danger of remaining inside immobilized vehicles during flood events.
• Immediate evacuation from vehicles is recommended to mitigate severe risks.
• Findings underscore the importance of such risk assessment studies for reducing flood-related casualties.