LIDAR: The Speed Enforcement Weapon of Choice

It's as easy as playing a video game at the local arcade; acquire target … steady, aim, shoot! But this is no game. In the world of traffic safety, when officers set out to work on catching drivers who race through crowded city streets, they want a tool in their arsenal that will accurately capture the speed data of these traffic violators. The weapon of choice in this game of cat and mouse is here: lidar.

Lidar (light detection and ranging) has become a popular tool with officers for speed enforcement, especially in congested traffic conditions. Unlike its brother, radar, the more widely recognized speed measurement tool, lidar allows for very specific target acquisition when attempting to determine the speed of a particular vehicle on a crowded roadway.

As lidar continues to make gains in popularity, a decline in radar sales has become noticeable. Carl Fors of Texas-based Speed Measurement Laboratories Inc., an expert in the field of development and evaluation of speed detection tools, reports laser gun sales now make up 30 percent of the speed enforcement electronics market, substantially higher than the 10 percent lasers had in 2004.

But make no mistake, lidar should not be purchased as a replacement for the current radar systems departments have in use. Instead, consider lidar as a new option for speed enforcement to enhance traffic safety efforts.

Something old, something new

Lidar uses a time-of-flight method for taking measurements to determine the target vehicle's speed. When a pulse is transmitted, the timer starts, and when that pulse hits its target and returns, the timer stops. The calculation of distance traveled over time is computed to determine speed. In many respects, this sort of technology may not sound like anything new. After all, we've been using radar in a similar fashion for years. The difference lies in the type and shape of the pulse being transmitted.

Radar shoots out a short, high-intensity burst of high-frequency radio waves in a cone-shaped pattern. Officers who have been through the painfully technical 40-hour Doppler radar training course know it will detect a variety of objects within that cone pattern, such as the closest target, the fastest moving target or the largest target. Officers are trained to differentiate and properly match targets down range to the radar readings they receive. Under most conditions, skilled users get good results with radar, and it is found to be most effective for open stretches of roadway. But for more congested areas, locking radar on a specific target is more difficult.

Lidar utilizes laser technology, allowing for superior target acquisition in high-volume traffic areas. According to Fors, "Laser systems are the most accurate means of providing traffic and speed analysis compared to other systems. A laser can pinpoint one vehicle in a group while radar can't. A laser beam is a mere 18 inches wide at 500 feet compared to a radar beam's width of some 150 feet." In congested traffic areas, an officer can very effectively use lidar to pick out a specific target, site it and read its speed without any concern for interference from other close-by targets.

This small beam width has another added benefit — it cannot be detected until after a speed measurement is already made. Testing of the most advanced detectors has shown that when officers aim properly (at the vehicle's front license plate instead of the windshield where the detector usually sits), the signal often goes undetected.

Lidar signals can be legally jammed, however. While radar jammers have been declared illegal by the FCC and cannot be lawfully produced in the United States, there are no laws prohibiting jamming police laser guns. Certain states, including California, Utah and Minnesota, have specific state laws banning the use and sale of laser jammers, though.

Lidar also is recognized by working police officers and traffic courts as a superior tool in targeting speeders. Officer Dan Hackett of the Paso Robles (California) Police Department has noticed a difference in how magistrates respond to testimony when they know the violator was captured on lidar. "Judges ask very few questions once they know I was using lidar," says Hackett. "They know how accurate it is, and it pretty much takes away the 'It wasn't me!' argument defendants try to raise."

Hackett has been using lidar for more than a year now. The Paso Robles PD received this new speed enforcement equipment as part of a California Office of Traffic Safety grant to address speed problems in their community. It has been especially effective in Hackett's assignment as a motorcycle officer. "We have particularly congested school zones in our city, and the lidar is much more accurate for shooting targets on crowded roadways," he notes.

Hackett also advocates that lidar is a good speed prevention measure. "When I'm working the lidar, it's no secret," he says. "I'm right out in traffic or parked visibly at the side of the road reading targets from my motorcycle. I'm more successful at catching violators, and the high visibility is a great deterrent to others passing by."

Although highly accurate, lidar still has its limitations. According to Bob Godsey, product manager for Kustom Signals, located in Lenexa, Kansas, lidar should augment other speed enforcement tools. Lidar benefits an officer under specific conditions, and it is an especially useful tool for motor cops. A highway patrol officer or a regular beat cop who works traffic enforcement from a car will more than likely choose a standard radar unit over lidar — and for good reasons. Lidar is a handheld device that has no "moving mode." "It all depends on the way you're doing your speed enforcement," Godsey says. "Radar will shoot further than lidar, up to 1 1/2 miles on a long open stretch of road. Because of the cone-shaped pattern of the radar waves, an officer parked at the side of the road can capture speed data from vehicles in both lanes and both directions." And of course, the ability to catch speeders in oncoming traffic when the radar is in "moving mode" is a huge benefit. Where some city police have trouble are those tight, congested areas where radar starts becoming ineffective as targets are more difficult to pinpoint. In those cases, partnering officers with a lidar unit in addition to other speed enforcement tools can be a real plus.

Getting creative

Officers are finding creative ways to address other traffic safety issues with lidar technology. In Colorado, state troopers use lidar to measure vehicle speed, but also to determine distance between vehicles when they suspect a car is following too closely. The troopers work in pairs to catch offenders; one is stationary, operating the lidar. When he gets a reading, the officer radios to his partner the speed of the lead vehicle and the distance the secondary vehicle is following behind. Troopers were targeting vehicles with less than a second between them at speeds of 75 mph.

Picture this

The best evidence is direct evidence, and it doesn't get much better than a picture. As technology continues to advance, lidar providers are scrambling to bring new features to market. The latest and greatest include the option to combine speed detection with digital photo evidence. At the time the lidar unit captures the speed violation, a digital picture of the evidence also is recorded. The image is displayed showing the vehicle, its speed, the lidar's target reticle and a time stamp of the infraction. The date, location, officer's name and other information can be added with a laptop. Photo evidence may be printed at the traffic enforcement site, or it can be downloaded, archived back at the office later for viewing, printing and more. In cases where violators are confronted with photo evidence at the scene of the infraction, Fors says, "the plead-guilty rates approach 100 percent."

Another popular change has been a reduction in the size of laser enforcement tools. Some units have become so small they are likened to a pair of binoculars that can get a reading through the windshield of a patrol car.

Depending on the model purchased, with a few optional accessories, lidar also can be an excellent tool for accident investigation.

The bottom line

Agencies of all sizes can benefit significantly from lidar. Every community has problem traffic corridors where roadways are congested and speed is a primary factor in collisions. If law enforcement management is going to ask for increased and more effective enforcement from their officers, they must provide the tools to do the job. At about $4,000 a pop, lidar is almost twice the cost of a standard radar unit. Laser systems are simply more expensive to make. The upfront investment also includes required lidar training for operators, above and beyond the standard Doppler radar course. Keep in mind that "you get what you pay for," and the extra expense up front is recouped in many ways. Lidar provides greater enforcement opportunities, less court time for officers, more guilty pleas/verdicts and an easier maintenance regimen.

Although lidar systems require a standard "once-over" inspection by the officer prior to each deployment, internal system checks are done automatically, and no calibration is required. This is a great time savings for the officer or technician assigned the job of keeping maintenance records on any speed enforcement devices.

Companies providing lidar products are sensitive to market pricing compared to other speed measurement tools, and they are competitively addressing the issue. Watch for improved lidar systems in the future that include additional features at lower costs. The more uses for the tool, the easier it is to justify the expense as departments get "more bang for their buck."

According to Gus Lora, product manager for the Traffic Safety Division at Laser Technology Inc., located in Centennial, Colorado, possibilities under development include Bluetooth technology, allowing for wireless download of speed data to an officer's pocket PC. Imagine how convenient this option would be for a "quick and dirty" speed survey to better assess problem areas in a city.

Lidar units are handheld and mobile, so they can be easily shared by patrol officers or those specifically assigned to traffic enforcement. Purchasing one or two units to augment other speed measurement tools is a small investment to test the benefits lidar has to offer, but don't be surprised if officers fight over who gets the unit each day. Cops go for what works, and if lidar's selling points prove true by providing greater accuracy, ease of use and air-tight evidence in court, there will never be a lidar sitting on the shelf in the equipment room.

Lidar may not be the revolutionary change in speed enforcement that radar was, but it may be a good "shot in the arm" to renew and improve traffic safety enforcement efforts.

Capt. Lisa Solomon is an 18-year veteran of the Paso Robles (California) Police Department. She has held many assignments throughout her career, including field training officer, D.A.R.E. officer and detective.