Emergency planners combine three streams of information into one evacuation timeline: how dangerous fire conditions are today, how much traffic the exit roads can actually carry, and how quickly the alert system reaches residents. This scene models a fire front advancing on a small community, with vehicles streaming out along the open evacuation routes once the alert fires.
Studies of real wildfire evacuations (e.g. the 2018 Camp Fire in California) found that road capacity — not vehicle speed — is usually the binding constraint: even short delays in issuing alerts can erase the entire safety margin once a fire is moving fast under wind-driven conditions.
A wildfire front advances on a small community while an alert tower, evacuation routes, and a stream of departing vehicles show how fire danger, wind, road capacity, and alert lead time combine into a single evacuation timeline.
The fire danger index and wind speed set how fast the flame front and embers advance; open road lanes set how quickly households can leave; alert lead time is the delay eaten out of the safety margin before the siren sounds.
Raise the danger index or wind speed to see the fire move faster, reduce open lanes to see the vehicle queue thin out, and increase alert lead time to see the evacuation clock start later relative to the fire's approach.
In several major wildfire evacuations, road throughput — not vehicle speed — was the binding constraint: planners now model route capacity in vehicles-per-minute-per-lane just like the estimate shown here.