A key question for the team is one that many hurricane evacuees know all too well: When is the best time to leave?
Clemson University
The beginning of hurricane season on Friday brings a sharp reminder that tens of millions of coastal residents could be called to grab their loved ones and flee inland for safety.
The enormous strain on the transportation system and the many decisions that must be made when the storms churn toward the coast are central to the research Pamela Murray-Tuite is conducting at Clemson University.
Murray-Tuite, an associate professor of civil engineering, is part of a nationwide team that tries to predict how many people will evacuate, when they will leave and how they will get to where they are going. The goal is to help smooth evacuations and ultimately save lives.
A key question for the team is one that many hurricane evacuees know all too well: When is the best time to leave?
A miscalculation can leave evacuees stranded in traffic for hours, or stuck in the storm’s path as the winds start to howl.
The potential danger will be especially pointed this year, coming just months after the most expensive hurricane season in history. Harvey, Irma and Maria cost $265 billion, caused hundreds of deaths and displaced hundreds of thousands of residents.
Murray-Tuite will be headed to one of the hardest-hit areas-- Dominica-- over the next few months to learn more. And she has co-written a book coming out soon, “Large-Scale Evacuation: The Analysis, Modeling, and Management of Emergency Relocation from Hazardous Areas.”
In the meantime, she sat down to talk more about her research.
You have a lot of access to data the general public does not. Would you have any helpful tips for residents who might be trying to decide whether to evacuate?
Hurricane season puts spotlight on evacuation research at Clemson
First, if you are at risk from a hazard and the most appropriate protective action is to evacuate, then you should. Evacuation notices, recommendations, or orders are provided after careful consideration. We know that not everyone who should evacuate does and that some people outside of the immediate risk area do evacuate even if not recommended to do so. This latter group can cause extra congestion. Another issue we’re looking at is trying to find the best time to evacuate. For example, if your strong preference is to travel during daylight hours, then our analysis will tell you the best time to leave during the day. What we’ve found in looking at the travel-time data so far is that the middle of the night is the best time to leave in terms of the least amount of congestion.
How would you explain what you do in simple terms?
We try to figure out how many households or people are going to leave the threatened area, when they’re going to leave, where they’re going to go, and how they’re going to get there. We use math to do that. And then we use traffic simulation to figure out what the traffic conditions are going to look like based on the demand that we’ve estimated. Then we try to make it better by doing things like changing the direction of the lanes. Or if we close certain ramps, we can make traffic flow smoother. To get survey data to develop the demand estimates, we work with our colleagues in social science. We also work with computer scientists to get Twitter data and do additional analysis.
What are some of your findings so far?
We have found that people will behave mostly according to their normal household responsibilities. So, if you normally pick up your children from school, in an emergency situation you are still the most likely person to pick them up. But we also found in an emergency, everyone is more likely to participate in household and evacuation preparation activities. We found that many households will buy food, water, fuel, and medicine and obtain cash before evacuating. We also found that people prefer to evacuate during daylight, travel by personal vehicle, and to stay with friends or family members.
I heard you went to Florida after Hurricane Irma hit. What was it like?
We visited Tampa and found it largely undamaged. We knew Tampa had some power outages, but power was restored by the time we got there. We were trying to get information about how people dealt with the power outage and what they might have done differently. We were looking for ties between use of power and use of transportation. We figured that if people didn’t have power and if schools were closed, they would go someplace that did have air conditioning, or they would organize more playdates for the kids, or they would go to restaurants or other public or commercial buildings to cool off. They could also go someplace else, such as another city.
It was an educational trip. We learned important things about how to talk to people in the situation where people don’t want to talk to strangers. People who did talk to us were very helpful.
How did you get interested in your research?
I’ve been interested in emergencies since I was a teenager. I started off going the medical route. I was on a rescue squad starting when I was age 16. One of the things I found was that there was so much traffic on the hill where I used to live that during rush hour you could not drive the quarter- or half-mile to the rescue squad building to get the ambulance. You could run there with no problem. Then I think the emergency idea carried over most naturally into these evacuations.
What brought you to Clemson?
I started in August 2017, and I came because it seemed like a great opportunity. The ad I responded to was looking for people in civil engineering who work well with social scientists. We’ve worked with a lot of social scientists, and it was a good fit. I came down from Virginia Tech for the interview, and I found people were very friendly. I liked the vision for the department, the environment, how supportive everyone is. It seemed like a really nice place to be.
What are you working on now?
We’re still working on a lot of evacuation issues. We’re also looking at some disaster recovery issues. We’re going to Dominica this summer and really looking forward to getting some first-hand experience in finding out more about the challenges the islands face and what to do when you’re out of power for more than six months. It’s a really different environment. It will be educational.