VASCAR

• While stationary. The officer manually measures a certain distance with a tape or other measuring device, dials that measurement into the VASCAR unit, then clicks the "time” switch when the car passes the first and second distance marks.


• While stationary, after having driven a set distance in his or her vehicle and using the odometer to enter that distance into the VASCAR unit. Again, the cop clicks the "time” switch when the car passes the first and second distance marks.


• While following you and allowing the VASCAR unit to take into account that the patrol car is also moving.


• While ahead of you, by pressing the "distance” switch twice as the officer passes between the two points, then the "time” switch twice as the officer watches you—through the rearview or side-view mirror—pass over the same two points.


• While driving in the opposite direction, by clicking the "time” switch as you pass a point well ahead of the patrol car and by simultaneously pressing the "time” and the "distance” buttons as your cars go past each other—setting the second point. Then the officer presses the "distance” switch as he or she reaches the first point where he or she started to time you. (The officer then makes a quick U-turn to pull you over.)

How VASCAR Fails

• the inability of the officer to accurately see when a distant car passes a distant point


• the officer’s reaction time (how long it takes him or her to push the button when a car passes a marker), and


• the accuracy of the odometer on the officer’s car.

• Officer’s Observation of Distant Point. When an officer times the passage of a car between two points, the officer must accurately record when the car passes each. This becomes more difficult the farther the officer is from either point. This is especially true at dusk, at night, and during bad weather, particularly fog or rain. For example, while VASCAR can be used at night, the officer must be able to see when vehicle headlights pass objects that may be illuminated poorly or not at all. Obviously, this is far more difficult than watching a car pass two nearby points at noon in good weather.


• Officer’s Reaction Time. Reaction time is the time between observing something and responding to it. Especially where the distance between the two points is only a few hundred feet, an officer’s reaction time will greatly affect the speed calculated by the VASCAR unit. Here’s why: The shorter the distance between the two points, the lower the elapsed time a speeding car will take to pass through those two points. For example, if the distance is only 100 feet, the car will pass the second point in only a second or two, meaning a reaction-time error of only a few tenths of a second will affect the accuracy by 20% or 30%. On the other hand, if the distance between the two points is 1,000 feet—which takes 15 seconds for a car going 40 mph to pass—a reaction-time error of a few tenths of a second will affect the accuracy by only 1% to 2%. In promotional materials, VASCAR manufacturers claim reaction time isn’t a factor, because they assume that the officer will anticipate, rather than react to, your car passing each point. They also argue that any delayed reaction will be the same for each click of the VASCAR unit, thereby canceling out the error. This is faulty reasoning. There’s no guarantee that the officer will delay the same interval when pushing the button as you pass the first and then the second points. In fact, the officer may do a much better job at the second point because the officer’s eyes have now been fixed on your car for quite some time, making the officer better prepared to press the button. The result can easily be that the officer has erroneously shortened the time and, thereby, increased your recorded speed. Reaction-time error is likely to be worst in the situation where the officer’s vehicle is approaching yours from the opposite direction. For example, if you’re doing 65 mph northbound, and an officer is doing the same speed southbound, your closing speed is 130 mph, or 191 feet per second. If you’re 500 feet away, the officer has little more than two seconds to look ahead, watch your vehicle pass one point, hit the "time switch,” then hit the "time” switch again simultaneously with the "distance” switch as your cars pass each other. The officer then has a few more seconds to hit the "distance” switch a second time, hopefully just as the officer passes the same point you passed when he or she hit the "time” switch the first time. Operating VASCAR in the opposite direction is so difficult to do well that some police agencies discourage officers from using it this way. Your main goal is to attack the officer’s reaction time through cross-examination (see this article), focusing your questions on the difficulty in timing a car’s passage past a distant point. When it is your turn to testify, tell the judge in detail (if true) that your speed was at or under the limit—or safely above it in a "presumed” speed limit state. Finally, be prepared to argue during your closing argument (see Chapters 12 and 13) how your testimony as well as the officer’s responses to your cross-examination questions raise a reasonable doubt over whether you were violating the speeding law.


• Odometer Error. The VASCAR unit’s accuracy depends on the accuracy of the police vehicle’s odometer, except where the distance between the two points is independently measured with a tape and dialed into the VASCAR unit. That is because the VASCAR gets its distance information via the patrol vehicle’s speedometer/odometer, to which it is connected. As the patrol vehicle moves forward, the cable linking the VASCAR unit to the speedometer/odometer turns, calculating how far the vehicle has moved from Point A to Point B. It is supposed to be recalibrated at least once a year. Tire wear and pressure can affect the accuracy of a speedometer. These factors will also affect odometer accuracy, because the odometer and speedometer both run off the same cable. For example, low tire pressure and tire wear on the police vehicle can result in a tire with a slightly smaller circumference than a new and properly inflated tire. The smaller wheel must make more revolutions to cover the same distance as a new tire. This results in erroneously high speedometer readings and in an exaggerated odometer distance reading. Since speed is distance divided by time, an erroneously high odometer distance fed into the VASCAR unit will result in an erroneously high speed reading.This type of error, however, is usually fairly small. For example, a 24-inch diameter tire that has lost one-quarter inch of tread will be 23.75 inches in diameter, a mere 2% less, so that the recorded distance and speed will be only 2% high. Still, this type of error, when added to other types of errors—like the ones listed above—may well result in an erroneous VASCAR reading. So, during cross-examination, ask when the VASCAR unit was last tested. If it was not tested recently, or the officer does not know when it was tested last, you should attack the accuracy of the test in your closing argument.