In the evolution of speed monitoring, the introduction of lidar in the last few years has allowed for pinpoint accuracy at long distances—something conventional radar units can't do because of the physical limitations THE3RDDEGREE > of strength and wavelength concentration.
Recently, the makers of the Digital Ally video capture systems handed me their most popular lidar model—the Laser Ally—to test. It's one of many lidar units the company offers, but is considered more of a "bread-and-butter" model.
To get a sense of its capabilities in the real world, I set up a controlled evaluation and let the unit do the talking. But before I get to the results, let's review the specifications of the Laser Ally.
The unit comes equipped with a bevy of options, and weighs a reasonable 2.5 lbs. Featuring a Class 1 laser, the Ally is rated to be accurate +/- 1 mph up to 6,000 feet in range, with an acquisition time of 1/3 second.
Technical accuracy is listed by Laser Ally as a beam spread of 2.5 feet at 1,000 feet, with distance accuracy of +/- .5 feet at one Sigma. Minimum operating range varies from 10–250 feet, depending on the mode selected.
The unit also features a unique obstruction mode, allowing it to be used around material such as chain-link fences and tree limbs. There's also a weather and range mode, and readings can be measured in approaching, receding and distance-over-time applications.
The Ally operates on two C batteries that last approximately 25 hours. The adjustable "power save" mode can be activated to further extend battery life.
Dimensionally, the Ally is about the size of a standard hand-held radar gun, and is easiest to hold two-handed.
Once locked onto a target, the reading in mph and feet is displayed on a high-resolution matrix display on the back of the unit, with the speed also displayed in the top viewfinder. The heads-up aiming unit is large and displays true-colors, making it easy to lock the red laser-aiming reticle on an approaching target.
The rest of the unit is encased in a shock-resistant, floating, internal, aluminum, optical bench structure with four-point external rubber cushions, which should make it durable throughout the long haul. The handle on the bottom of the unit is a good size and holds the batteries. It's also waterproof.
But the proof is in the pudding. I conducted a controlled test alongside a rural road outside Phoenix in order to find out how the Laser Ally performed.
Specifically, it was a level, four-lane road with a divided median, with no obstructions lining the roadway between my location and the acquisition point approximately 900 feet away. Although the Laser Ally is rated to 6,000 feet, my chosen distance was consistent with my experience in speed enforcement. It allowed enough time for clear target identification, acquisition and theoretical apprehension.
The posted speed limit was 50 mph and my position was within 20 feet of the roadway edge. I chose to lock onto approaching vehicles in the No. 2 travel lane, minimizing any angular distortion. It was Saturday morning and traffic flow consisted of packs of four to five vehicles every minute or two. The 100-degree weather was clear.
I performed approximately 15–20 readings on the Ally to get used to it, with the clocking parameters set to "approach" at maximum range. Once familiarized, I recorded 15 clocks. I chose vehicles of various sizes, colors and shapes, though with the laser unit, it didn't seem to matter given the aforementioned beam spread of 2.5 feet at 1,000 feet.
Upon conclusion and after tallying the numbers, some performance indicators were clear. First, the average lock-on distance for the Ally was 638 feet, with target acquisition time of less than one second to three seconds long. The large heads-up display made it easy to identify targets and, ergonomically speaking, the unit was comfortable and easy to hold with a two-handed grip. All displays were easy to read, even in bright sunlight. The audio tones were also easy to hear and helpful.
Overall, I was impressed with the Laser Ally. Even though 6,000 feet might be too long for realistic targeting, the capability is there, and that's impressive. If your department works an area where waterproofing is a necessity and the size of the unit isn't an issue, the Laser Ally makes a solid and impressively intuitive choice.
JP Molnar, Law Officer's Cruiser Corner columnist, is a former state trooper and has been teaching EVOC since 1991 for numerous agencies. He holds a master's in adult education and training, and is a contract instructional designer and performance/public safety driving consultant. He has also raced cars for 25 years and has taught at numerous high-performance racing schools.
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