There's one fundamental thing to keep in mind when it comes to border protection. Knowing and tracking an intruder's direction of travel can be much more important than building a physical barrier. Human beings are very creative when it comes to getting around things that block their progress, so once a border is breached, actual enforcement happens after the crossing.
A couple of years ago I had a chance to meet a group of border patrol agents from Texas. They were in Washington D.C. to participate in a conference focused on police and national security issues.
We talked about ways to close the holes in the U.S. Mexican border and the subject of walls came up. One of the officers rolled his eyes. I don't remember his exact words but he stressed that walls are great for urban areas, but they have minimal impact in rural areas where the nearest border patrol agent might be located miles away.
The same can be said for sensors – if those sensors are located only along the border itself.
Spread too Thin
Once someone manages to illegally cross a border, including a border wall, the agent said, they can run in any direction. When a border patrol officer arrives in the area where a sensor has been tripped, he or she has to figure out which direction the intruder went. Even with a helicopter, that can mean searching many miles of terrain, and people can be very good at hiding.
What he really wanted to see was an array of sensors stretching back several miles from the border. That way, not only is the initial intrusion detected, but other sensors eventually are triggered to show which direction the intruder is heading. Such sensors can include electro-optical devices, infrared cameras, radar, ground vibration measurements, and more. Such sensor arrays can be solar powered to allow for installation anywhere.
Connections can be made in a few different ways, including small cell wireless points of presence or via wireless mesh networks. In this type of network, the connection is spread out over multiple (sometimes up to hundreds) of wireless mesh nodes that "talk" to each other to share the network connection. The individual nodes are radio transmitters that function like Wi-Fi routers. They include software controls with rules on how to interact both with other controllers and with the larger network.
Data packets travel by hopping wirelessly from node to node. Dynamic routing allows the nodes to choose the most logical path based on traffic. Thus, even if someone destroys a sensor or a router, the packets are re-routed and the information gets through.
The U.S. Customs and Border Patrol already has a similar effort underway. It's called the Integrated Fixed Towers Program. The agency told Congress last year that a pilot program showed the initial installed towers met their operational requirements and the program was ready to progress.
In sparsely populated areas, these towers seem to make more sense than a physical wall.
Rural Areas Are the "Long Tail "of Border Crossings
Border walls can and do have an effect in high-traffic areas. But running a wall for the full length of the U.S. - Mexico border can never be physically effective nor cost effective. Here's why.
A physical wall does nothing to address things like makeshift ladders, tunnels or even old airplanes that are abandoned after quick one-way trips.
There are about 21,000 border agents to protect roughly 1,954 miles of border. Assuming each has an 8 hour shift and a 40 hour week, that leaves (in theory) one on-duty agent for every few miles or so. But because more agents are assigned to high-traffic crossings, and because of vacations, sick days etc. the actually gaps between agents out in the countryside can be 40 miles or more.
Just as marketers need to get creative to address the long tail of a group of consumers, the federal government needs to get creative when addressing the long tail of rural borders, where there are many miles to cover and where potential border crossers are very spread out.
There are already about 650 miles of walls along the southern U.S. border. So far the cost has reached roughly $7 billion. Thus we are looking at at least $14 billion more to complete a full wall. (An MIT Technology Review article placed the estimate closer to $40 billion.) That's a lot to spend on an effort that might slow, but certainly not stop illegal border crossings.
There's also one last big hurdle - much of the land where a fence would need to be built is privately owned. There would be many legal issues if land owners don't want a fence in their backyard. But sensor arrays can be stretched out and placed creatively to avoid these issues.
In reality, any border in any country can best be protected by using walls in some areas, fences in others, and a lot of electronics focused on the vast stretches of land located in rural areas. In the U.S., a budget of $14 billion to $40 billion can go a lot farther when it's targeted at sensors, cameras and networks instead of steel and concrete. But, most important, an electronic approach actually solves the problem of determining which direction an intruder is heading.
Since border patrol agents themselves say that's what they really need, this approach certainly should be a big part of the wall discussion.