If there’s one traffic crime police like to crack down on, it’s speeding. Catching offenders is relatively straightforward, dishing out fines is easy, and prosecuting the crime is by-and-large a slam dunk. Few motorists have any wiggle room to fight back against such charges, but the Iowa State Patrol just gave a bunch of speeders a chance to dispute their tickets.
You see, last weekend was a big one for the Iowa State Patrol. Troopers were out working a “speed project” on I-35 between Oralabor and 1st street. The troopers stopped 30 cars for speeding, and one driver was even jailed after they were allegedly caught doing a mighty 144 mph.
There was just one problem. When the State Patrol posted to Facebook, they revealed one little mistake. The stopwatch they were using was set to kilometers instead of miles.
Think before you post.Â
Oopsie
Given that a driver was allegedly caught speeding at 144 mph, the story made the news in a ton of outlets across Iowa. WOC1420, Local 5 News, and WHO13 all ran with the news of a speeder caught doing 144 mph in a 65 mph zone. Police quoted the driver, Thomas Peterson, as saying his reason for speeding was that he “wanted to have a little fun.” His 2009 BMW was towed, and he was charged with speeding and reckless driving.
This is where the story gets interesting. Iowa State Patrol wanted to boast about its big win on the weekend, and posted an image to Facebook. The measurements weren’t taken using a radar or lidar speed gun. Instead, the post showed the stopwatch that police were using to time drivers over a set distance in order to figure out their speed—a technique called VASCAR, or Visual Average Speed Computer And Recorder. The stopwatch, a Robic SC-899 Triple Timer model, was showing a speed of 144… kilometers per hour.
This naturally led numerous commentators to call out the operation as a farce. Many pointed out that 144 km/h is actually just 90 mph—still speeding, but to a far less egregious amount. However, the truth may be a touch more complex. Let’s take a closer look at the stopwatch and the math.
Basically, the Robic SC-899 is just a stopwatch that does a little extra math. You tell it the distance you’re timing over, and it’ll calculate the speed of an object based on how long it takes to travel that distance. We can see the stopwatch is displaying the “KM” unit, indicating it is set to kilometers. This is what triggered the controversy. The stopwatch reads 6.25 seconds, and displays a speed of 144 km/h. If we work backwards, we can calculate the distance the stopwatch is set to measure over.
Well, would you look at that—we can see the programmed distance comes out to a perfect 0.25 kilometers (0.15 miles). Here’s where you need to do a little thinking. What sounds more likely—did the police plan to measure speeders over an 0.15-mile stretch, and then accidentally switch the stopwatch into kilometers without noticing? Or did they intend to measure over a quarter-mile (0.25 miles) and just entered it as kilometers by mistake? I’d wager the latter. Particularly given this particular stopwatch doesn’t have a way to switch units after initial setup. In any case, The Autopian has reached out to the Iowa State Patrol for comment.
The thing is, it actually doesn’t matter whether you have the SC-899 stopwatch set to kilometers or miles, as long as you’re consistent. If you enter the measured distance in miles, the output will be in miles, even if you told the stopwatch you’re working in kilometers. The stopwatch is just dividing the distance by time. If you do 0.25 units of distance divided by 6.25 seconds, you get 0.04 units of distance per second—which equals 144 units of distance per hour. If you meant miles when you keyed it in, you’re reading an answer in miles per hour. If you meant kilometers, you’re getting kilometers per hour. There’s also nothing in the stopwatch manual about changing the displayed units after initial setup—so it’s not like they just hit a button and switched from km/h to mph.
Given that the US is so obsessed with miles—and quarter-miles specifically—it seems far more likely that the police were measuring over this distance, and just ignored the units. If they punched in 0.25 for a quarter mile, the resulting speed would be in miles, and everything would be all good. To actually measure wrongly would require more effort. To get the results seen here, you’d have to be measuring over a distance of 0.15 miles, but enter it as 0.25 kilometers. Then you’d have to forget to convert the results back to miles after reading them off the stopwatch.
The fact is that this questionable post could give speeders some wiggle room to challenge their tickets. In posting this image, the Iowa State Patrol has created questions about whether they were using their equipment properly. There are a great many comments out there already calling them out for this very fact. If the State Patrol can prove it was measuring over two points that were indeed 0.25 miles apart, they shouldn’t have any problems. Still, they’ll have to go over this long-winded explanation in court just like I have done here.
The Iowa State Patrol didn’t make the same mistake when they did this back in June. Indeed, you note that they measured about 6.61 seconds and the result came out as 136 mph—suggesting an 0.25-mile measurement distance. Measurements are usually made via specific road markings that are painted at regular 0.25-mile intervals.
Ultimately, you’d hope that those doing speed enforcement are setting their gear up correctly. Particularly where public perception is a concern. Motorists hate getting speeding tickets at the best of times. It’s all the more frustrating when it feels inaccurate, unjustified, or unfair.
Image credits: Iowa State Patrol, FlightRadar
In Toronto, and I’m sure lots of other places, we have temporary electronic signs that show approaching motorists what speed they are going. They are fun for pedestrians who know that if you frantically wave your arms above your head, they will mistake you for a vehicle. They are wildly inaccurate, probably just a performative gimmick, but I have been clocked at up to 50KM per hour while jogging. 😉
As much as I think the premise for a lot of speeding tickets is a farce at best, how about we watch neighborhoods and other places with higher pedestrian density. I’d wager that 90 in a 70 is much less dangerous than say 45 in a 25.
Yes, that is very true, and 44 in a 25 would not technically be considered reckless driving in Virginia, even though it’s nearly double the speed limit, but 86 in a 70 would be