Saturday, April 23, 2011

Automating Wrongful Convictions (with Demon Devices from Hell)

Given that we have 2.5 million of our fellow Americans behind bars, and given that 10% of them may be innocent of the crime for which they are serving time, I believe that some form of automation is necessary to identify those who might be innocent. My efforts to automate matters have so far been somewhat unsuccessful, non-productive, ineffectual, feeble.

The State, aka The Man, has been much more successful at automating and increasing convictions. A natural fallout of automating and increasing convictions is automating and increasing wrongful convictions. Consider the case of Will Foreman. The State has charged Will with 40 crimes. So far, Will has prevailed on the first 5 cases to be heard. That leaves only 35 more. I expect he will prevail on each of them.

When I write about specific cases or individuals, I usually write about someone wrongfully executed (such as Cameron Todd Willingham), or someone serving a life sentence for a crime he did not commit (such as Byron Case) or someone serving half a century for a crime that never happened (such as Michael Ledford). I typically do not write of someone who has received speeding tickets.

In fact, let me think here. Yup. I believe this is the very first time, ever, that I have written about wrongful speeding tickets. It won't be the last. This post will be the first of a short series discussing the implications of Will Foreman's speeding tickets.

I don't write of Will and his speeding tickets because he is an acquaintance of any sort. I've never met or  communicated with him in any fashion. I had never even heard of him before I read of his situation. Also, I don't write of him because he needs my help. He certainly does not. I write of him because his situation is a microcosm of our justice system not living up to its ideals. I write of him because I hope doing so will help you see the bigger picture, the more serious injustice, the wrongful incarceration of perhaps a quarter million of our own.

The Machine

To understand the injustice the State of Maryland is attempting to heap upon Will Foreman, you must first understand the automated speed camera used to wrongfully ensnare him. I therefore refer you to a brochure for the Optotraffic DLS-10S Automated Speed Enforcer. Though that brochure is marked CONFIDENTIAL and PROPRIETARY, it is available on Google Docs for all to view. From that brochure, I present this sketch of the demon device.

I provide also this description of how the demonic device works, at least in theory.
The DLS-10S implements a simple time-distance method for speed determination. A Lane Sensor that contains two optical sensors monitors each traffic lane. The sensors scan the road in the direction perpendicular to the line of traffic. When a vehicle is detected, both sensors acquire its unique profile and record the time when a sensor detected the object. Since the distance between the sensors is well known, the speed can be determined precisely as follows: 
Measured Speed = Distance/Time
where the "Distance" is the distance between the two laser beams that cross the lane and the "Time" is the time between the vehicle breaking each of the beans.
Now you can see why the document was marked both CONFIDENTIAL and PROPRIETARY. If that equation ever got out, no telling what might happen.

The machine has to perform three tasks very well. First, it has insure that the two beams pointing at any lane are parallel. (Under no circumstance should the beams be allowed to cross.)

Second, it has to measure time precisely. This it can do, to within millionths of a second.

Third, it must be able to precisely determine when a car has entered (and/or left) its field of view. This is the most difficult task. This is where the DLS-10S guesses. This is where it gets things wrong.

I'll leave further discussion of the machine's inner working for a following post.

The Photos

Not only does the DLS-10S estimate the speed of a car, it takes two digital photographs of the car as the car "speeds" away. The purpose of the pictures is to capture an image of the license plate so that the registered owner of the car can be ticketed. Only one photo would be sufficient most of the time, but two photos reduces the chance of having the plate blocked by another car.

If the objective of the automated system is to reduce the extent of speeding, the photos turn out not be necessary. The digital signs that simply inform you of your current speed turn out to be quite effective.

However, if the objective is to suck money from the pockets of scofflaws, then you need the photos. In the previously mentioned brochure, the fine folks at Optotraffic provide two example photos. I show them below.

Each photo displays the location, date, posted speed limit, and measured speed of the car. In this case, the posted speed limit was 30 miles per hour and the measured speed was 42 miles per hour. You are looking at a traffic scofflaw. You are looking at a speeder.

(It's perhaps only coincidental that the car is declared to be traveling 12 mph above the speed limit. Maryland law requires a 12 mph threshold before an automated ticket can be issued.)

Each photo also shows the time the photo was taken, measured to thousandths of a second. The second photo even does some math for you. It subtracts the two times and displays the difference. In this case it is 0.406 seconds.

Taking a lead from Will Foreman, I overlaid the two pictures. (I used Gimp to create the overlays. If any of you want to use or learn Photoshop but can't afford it, Gimp is a free and excellent alternative.)

Pretty cool idea. What you see is two images of the same car allegedly traveling at 42 mph. The two images are separated by approximately one car length. That means the car traveled approximately two car lengths in 0.406 seconds. Approximately is the key word here. It's extremely difficult to determine distances accurately from a photo such as the one above, due to perspective issues. Note how small the car appears to be in the front image compared to the rear image. Perspective views distort dimensions in complex fashion.

The Case of Will Foreman

Will Foreman is the owner of Eastover Auto Supply in Oxon Hill, Maryland. If you know where to look on his web site, you can get a coupon for $5 off any purchase of $50 or more. Heck, you don't need to go  to his web site. I'll post the coupon here. Click to enlarge and see it in all its wonder.

Note that the coupon expired last century. Maybe he will honor it anyway. If you happen to drop into his store, tell him I said "Hi."

Eastover has multiple company vehicles. Eastover's employees drive those vehicles as part of their job. Eastover's employees suddenly started getting lots of traffic tickets for speeding through the city of Forest Heights. As owner of the vehicles, Will was on the hook to pay those tickets. That didn't make him very happy. He threatened to pass the cost of the tickets along to his employees.

That didn't make Will's employees very happy. They claimed they weren't speeding. They claimed they had learned where the traps were. They claimed that even though they conscientiously observed the speed limit knowing of the speed traps, they were still being ticketed. After a while, the employees began skirting Forest Heights altogether. They thereby added unnecessary miles to their trips, burned more fuel than necessary, burdened their employer with higher fuel costs, and pumped even more life-threatening carbon dioxide into the atmosphere. (Al Gore should be all over this once he reads my post. If you relay it to him, send him this one as well. And tell him I said "Hi.")

By the time Will's employees had given up even driving down what had become known as the Forest Heights Toll Road, they had racked up 40 tickets. At $40 per ticket, Will was staring at $1600 in fines. Somewhere along the line, however, Will had a flash of brilliance. He decided to overlay the two photos that came with each of his tickets. Here's one result, from the Stop Big Brother Maryland web site. (Those guys are all over the situation. Big time.)

The photo displays a posted speed limit of 35 mph and a measured speed limit of 56 mph. In my assessment, that's a bunch of crap. Will provides a somewhat more analytic assessment.
The length of this pickup is about 16 feet., meaning the truck should have traveled 1.82 truck-lengths (or 1 length + another 13.18 feet) to move at this speed.  IT IS NOT EVEN CLOSE TO THAT DISTANCE.  We've added guidelines to compare the image, showing that the distance is 1 length + the gap between the front and back of the two truck images.  That gap is much less than half a truck-length. We estimate this to be less than 4 feet based on the size of the wheel-wells.  That would work out to a total distance of less than 20 feet, which given the interval of 0.363s would be just under 38mph.  This indicates an error of 18mph, and speed 9mph below the threshold for issuing speed camera tickets under state law (47mph in this case).
You don't need to work through the math to see that the truck was not traveling anywhere near 56 miles per hour. Look again at the my composite photo in the Optotraffic example. There the car is allegedly traveling only 42 miles per hour, and look how far apart those images are separated. By comparison, the Eastover Auto Supply truck images are barely separated. By comparison, the Eastover truck is traveling much closer to the 35 mph limit, just as Will calculated.

Let's look at a second, even more egregious ticket.

Once again the time difference between the two photos is 0.363 seconds, and once again Will's trucks are just barely separated. Once again, it seems as if his trucks are travelling very near 35 mph. (It's hard to assess the speed much more accurately than that, given the perspective of the photos.)

In this case, however, the spawn-of-the-devil machine claims Will's truck was traveling at 76 mph. (Insert 5 exclamation marks here.)

The Trial(s)

Most people don't fight their tickets. Most people simply swear up a storm and pay the $40 ticket by mail.  Only a few go to court, appear before a judge (no jury trial allowed), and mount a defense. Even fewer prevail. Will was an exception.

I quote now from the article that first brought his case to my attention.
Five times and counting before three different judges, the Prince George’s County business owner has used a computer and a calculation to cast reasonable doubt on the reliability of the soulless traffic enforcers.
After a judge threw out two of his tickets Wednesday, Mr. Foreman said he is confident he has exposed systemic inaccuracies in the systems that generate millions of dollars a year for town, city and county governments.
He wasn’t the only one to employ the defense Wednesday. Two other men were found not guilty of speeding offenses before a Hyattsville District judge during the same court session using the same technique.
“You’ve produced an elegant defense and I’m sufficiently doubtful,” Judge Mark T. O’Brien said to William Adams, after hearing evidence that his Subaru was traveling below the 35-mph limit - and not 50 mph as the ticket indicated. ...
While Judge O’Brien let Mr. Foreman off the hook, he ruled against several other accused speeders who based their not-guilty pleas largely on gut feelings that the cameras were flawed, while reducing the fines for some who pleaded guilty.
And there you have it. The last paragraph sadly epitomizes the state of our judicial system. Those who plead guilty are treated more favorably than those who have the temerity to defend themselves. Everyone is presumed guilty, and only those who can mount a stout defense have any hope of a favorable verdict. The state is not required to prove anything beyond a reasonable doubt. Even the flimsiest of evidence is sufficient to sustain a guilty verdict.

Even though the judge had just learned that the Optotraffic DLS-10S Automated Speed Enforcer frequently provided false evidence for the state, the judge took the word of the machine over the word of a defendant. The judge merely presumed the machine was right, and merely presumed the defendant was guilty.

In doing so, he suborned perjury, by a machine no less. I guess he decided such subornation was necessary for the rapid administration of justice. If a few people were wrongfully convicted along the way, if a few pleaded guilty to avoid even harsher sentences, then so be it. You can't make a judicial omlette without breaking a few heads.

The series continues here.