Chart of the Day: Necessary Road Space per Traffic Mode for Houston Metro Evacuation

Traffic during the evacuation of Hurricane Rita in 2005.

Right now, even in Minnesota, all eyes are on the flooding and storm impact in Houston, Texas. Earlier today I read an article about why the Mayor of Houston did not put out a call for an evacuation of the city ahead of the landfall of Hurricane Harvey. It turns out the answer was that a premature evacuation, and the resulting congestion on Houston area freeways, was also something of a disaster.

Here’s the key point from the NPR article:

In 2005, just a few weeks after Hurricane Katrina devastated New Orleans, Hurricane Rita made its way toward Houston. Rita was even stronger than Katrina — and Houstonians had just witnessed what happened to New Orleans residents who decided to wait out the storm. Nobody wanted to repeat that mistake.

The result: The largest evacuation in U.S. history, according to PBS. Texas legislators estimated that 3.7 million people left the Houston region in the evacuation effort.

The evacuation was a disaster in itself. NPR’s John McChesney reported from the scene in 2005:

“In searing 100-degree heat, cars crept up north I-45, windows down, air conditioning off to save precious gasoline. The traffic jam stretched for over 100 miles and has been going on for over a day and a half. … Gasoline was not to be found along the interstate and cars that ran dry made the gridlock even worse. Abandoned vehicles littered the shoulder lanes.”

Dozens of people died on the road — in a horrific bus fire, in traffic accidents, of heat stroke.

The line that caught my eye was this one, a quote from Houston Mayor Sylvester Turner:

“You literally cannot put 6.5 million people on the road.”

Especially given Houston’s famously mammoth highways, that’s quite the statement!

Anyway, here’s your chart. Via Twitter user Alan Kessler, it’s actually a pair of charts. The first shows the amount of space taken up by a car, on average:

The second illustrates how much land that might be in the Houston area:

On Twitter, Kessler writes that “If you had the buses, you could fit them in about 49M sq.ft. (~18 sq. mi) Here’s 11M sq. ft. for scale.” I guess the lesson here is that if you’re going to evacuate a city, use buses.

Meanwhile, keep the people of Houston in your thoughts.

2 thoughts on “Chart of the Day: Necessary Road Space per Traffic Mode for Houston Metro Evacuation

  1. Monte Castleman

    Suggesting everyone just take the bus to solve the evacuation problem is as simplistic and unworkable as suggesting everyone take the bus to solve our daily commute congestion problem.

    1) It appears authorities are swamped just getting enough buses and finding enough places for the people that are using buses. Imagine if the Twin Cities were to be evacuated, where do you drop 3 million people? Where do you find enough buses to move them. Given the option a substantial number will take care of themselves and disperse- go rent a motel room in Sioux Falls, stay with relatives in Fargo or Balaton. You’d either have to find room for all 3 million people in the metro in shelters or provide bus service to every small town where people might go, instead of just the people that cannot evacuate by themselves.

    2) If you put people on buses, where do you put their pets. Yes, this is a real issue. The bottom line is that pets are like family regardless of their legal status, and people will not abandon them to fend for themselves and die. Part of the reason Katrina was a mess is thousands of people refused to evacuate and leave their pets behind. When a train derailed and caught fire in Weyauwega, WI in 1996 they made people evacuate without their pets. Because of that after a day or two people started entering illegally to retrieve them, and authorities finally had to go into the danger zone with to rescue them what protection they had- armored personal carriers and flak vests to stop people from doing it on their own. Maybe your kids hamster can ride on his lap, but what if the family has four German Shepard’s. If they go to their relatives house in Little Falls by car they can go in the back yard, but if everyone from the metro went to shelters, how would these cities cope with all the pets of the evacuees that are taken their by bus? Because of these incidents it’s now a requirement that evacuation plans

    3) How do you enforce this? Put guards at the Fish Lake interchange and turn back anyone in a private vehicle trying to leave town? Wouldn’t that defeat the whole purpose of not causing congestion? Is that even legal? A substantial number of people are going to prefer to stay with relatives that have a shower and washing machine rather than a cot in say the Mayo Civic Center. And you can fit more clothes and valuables in the back of your SUV that you’re upside down on as opposed to what you can carry on a bus.

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