We’ve all seen it in our rearview mirrors….the hood of the car behind you. Why the hood? Because the damn car is too close to see the headlights. Quick brake check? Gets your point across, but not at all safe (or smart). The smart move is simply moving over and letting the impatient assclown go along his/her way.
I’m not saying that I miss my Dad’s old ’65 GMC pickup when I had a tailgater. That thing was like a friggin’ tank and it would be no problem to remind tailgaters that their proffered method of following me wasn’t the best way. No, no…to say that would be irresponsible and incredibly foolish.
About a year ago, my department issued the motors lidars with the DBC (Distance Between Cars) function. The DBC works by shooting both vehicles either as they approach (front bumpers) or as they pass (rear bumpers). The lidar calculates the speed of both vehicles, distances from the operator’s location, the distance between the cars (in both time and feet), and the time between both shots.
Human perception/reaction time has long been understood to be 1.5 seconds. Folks that are way smarter than me and probably have more initials behind their names and degrees on their walls conducted enough experiments, studies, and scientific type stuff to determine that time. What does that mean in layman’s terms? It takes .75 seconds for your average human to perceive, in this example, what the driver ahead of you is doing, and an additional .75 seconds to safely react to it. That totals 1.5 seconds from start to finish.
Consequently, when I shoot two vehicles with the DBC function and I get a digital readout with the time between the two cars. That is to say, it calculates how quickly one car will pass the same point the car in front of it just passed. I feel perfectly justified in stopping and citing anything less than one second. More often than not, though, I give an additional benefit of the doubt of another .1 second. Generous, no?
Here’s the part where the judge in my jurisdiction seems to get stuck on. Let’s say the speed limit is 45 mph. I see two cars and the second is too close to the first. I shoot both cars and get a display of .88 seconds and a distance of 53′. The second vehicle is not violating the basic speed law at 43 mph. Or is he? CVC 22350 requires drivers to “have due regard for the traffic upon the highway”. If the vehicle in front of the tailgater is too close for safety, doesn’t that violate 22350? Maybe, but CVC 21703 is more specific with regard to tailgating, “The driver of a motor vehicle shall not follow another vehicle more closely than is reasonable and prudent, having due regard for the speed of such vehicle and the traffic upon, and the condition of, the roadway.”
It seems because the speed and distance in the aforementioned example is what it is, the judge takes exception to the rule. Allow me to explain further…
43 mph correlates to about 63 fps (feet per second). In 1.5 seconds, the vehicle will travel about 94.5 feet. If the distance between the cars is 53′, it is nearly physiologically impossible for a human to avoid a collision if the driver in front aggressively brakes for any reason at that speed.
It’s an anomaly for the judge to take exception to tailgating. I’ve testified to 21703 a couple dozen times and I’ve written quite a few that never went to trial. In my opinion, it’s a fantastic cite and helps reduce collisions if people are more aware of how close they are traveling behind the car in front of them. So many of our rear-end collisions cite speeding as the primary collision factor when in fact tailgating is more likely the culprit. Unfortunately, witnesses are scarce and speeding is easier to prove than tailgating without corroboration from a witness or involved party.
I’ll keep writing them. If the judge sees fit to dismiss the occasional violation, it’s no skin of my nose. As far as I’m concerned, I’m making the streets safer by writing this particular violation. So many people simply don’t realize how close they actually are to the car in front of them. And it’s awful damn hard to argue with the lidar.