Recently, I served on a jury that heard a case involving a driver who had been drinking and who had hit a black cow while driving on a dark, unlit road at 1 AM. [I am not making any of this up] One of the things I noted was how often mathematics came up and, unfortunately, how little about it the attorneys for either side seemed to understand.
In our state, you can be convicted of DUI if your blood alcohol level is 0.08. The arresting officer apparently thought he had such a case because he did not gather the kind of evidence at the scene that one would need to prosecute a different kind of case. But by the time he got around to testing the defendant, using the state's only approved breathalyzer instrument, the blood alcohol level reported was just 0.07. Because the prosecution called witnesses to support the accuracy and precision of the instrument, as well as the state toxicologist, I at first thought they were going to make some argument about how much the blood alcohol level might have dropped in that two-hour period and still try to nail the defendent on a DUI charge [in that case, other math would have come into play because the several readings on the machine had to be within 10% of their average, the temperature reading of something had to be 34 degrees Celsius, and so forth]. But, it turned out that the prosecution had changed its mind and wanted to try the defendent for "Negligent driving in the first degree"--basically, driving in such a way as to endanger people or property AND driving after drinking--no need to meet the 0.08 standard.
At this point, the type of math involved changed. One defense witness [who had been riding in the pick-up truck involved] claimed he had first noticed some cows in the road just after crossing an intersection. He estimated that the distance to the cows had been about 150 feet. He claimed that the driver had moved into the other lane and decelerated in order to avoid hitting the cows he could see [they were black and white cows], but that just after passing those cows they hit an all black cow which they hadn't seen in the other lane. He also estimated that it took about three seconds to cover the distance from the intersection to the cows. Now, 150 feet in three seconds is OK--around 34 miles per hour [I suspect the witness had had plenty of time to work all that out in the preparation of his story]. But the prosecuting attorney kept referring to the defendent covering 150 YARDS in three seconds--a high rate of speed indeed for a small blacktop road on a dark night. At first, I assumed it was just a slip of the tongue, but she kept doing it over and over. The defense attorney objected to this and, of course the judge sustained. But, then, the defense attorney tried to persuade the jury that his client had been driving ONLY 66 Miles per second! [He could have made it coast to coast during one commercial break]. Obviously he meant to say 66 feet per second, which is 45 miles per hour--the posted speed limit on that road. Again, it was probably a slip of the tongue, but I wonder. I suspect that most of us--even had we made a slip of the tongue would have "heard" what we said and realized that something did not sound quite right.
But what was bothering me--and which was never brought up by the prosecuting attorney, is that the arresting officer had earlier testified that the distance from the intersection to the "point of impact" where the truck had hit the cow--was 0.15 miles. And we had a visual display hand drawn by the officer showing the general lay out of the scene. Now I did some mental math [the kind advocated by the NCTM Standards for elementary students] and decided that it was "about 800 feet." So, I wondered if the truck had actually gone 800 feet--not 150 feet during that estimated three seconds. Or, even knocking 100 feet off to allow them to get past the intersection, knocking another 100 feet off to allow for a difference between first encountering the cows and having passed them, we're still talking 200 feet per second--136 miles per hour! Had I been the prosecuting attorney, I think I could have convinced the jury--using the defense's own witness--that either the witness was very unreliable in his recollections [because he had been drinking, also] or that the truck had indeed been traveling at a very high rate of speed. But the prosecuting attorney never said anything, and I believe it was because she never realized what a large discrepancy there was between 150 feet and 0.15 miles.
To make a long story short, the most crucial information was never brought up for discussion by the attorney, the visual with all the necessary information was not available to the jury [I asked for it but it had never been admitted as official evidence, so the request was denied], and so because the jurors had "reasonable doubt" concerning the negligent driving part, they found the defendent "not guilty." I personally suspect he was guilty as hell.
Kind of makes you nervous concerning the future of our democracy, does it not?
Ron Ward/Western Washington University/Bellingham, WA