Laser device takes on tailgating

     A growing number of law enforcement agencies are discovering the benefits of a new tool for an old traffic enforcement problem: following too closely. For years, traffic officers have struggled to bring tailgating violators to justice in courts, but without definitive proof their efforts have been stymied.

     The problem is that there was no means of measuring the speed and distance between the offender and the car ahead of him or her. More precisely, officers have been powerless to consistently enforce the highway safety industry's 3-second rule. This rule is a safety guideline applied to vehicles on major roads or highways that suggests the minimum distance a driver should be from the vehicle in front of him or her. Following this rule, the distance traveled in 3 seconds is the minimum distance. Without a detection method to enforce the rule, visual determination of vehicle separation distances is subjective, and relies on the judgment of the officer.

     Speeding, and its most formidable accomplice, tailgating, receive top billing as factors in today's grim highway accident and death statistics. The National Highway Traffic Safety Administration (NHTSA) cites speeding as a contributing factor in approximately 30 percent of fatal crashes. In addition, the National Road Safety Foundation reports aggressive driving behaviors, from which road rage and possibly tailgating have emerged, are linked to half of all car crashes.

     Barbara Harsha, executive director for the Governors Highway Safety Association (GHSA), is distressed about speeding based on statistics that highlight the issue. "[Speeding factors into] about a third of all vehicle-related fatalities and it's been at that level for the last decade, which says that we're not making any progress," Harsha says.

     During the past few years, Centennial, Colorado-based Laser Technology Inc.(LTI), a maker of commercial speed detection laser systems, has developed a product called "Distance Between Cars" (DBC), a software code built into the company's lasers that can calculate accurate measurements between vehicles, both in distance and time. According to LTI, Distance Between Cars measures the back-to-front bumper separation between two vehicles. To date, the company's DBC software is the only innovation of its kind within the LIDAR (short for light detection and ranging) category of speed enforcement tools able to pinpoint tailgating infractions and withstand courtroom scrutiny.

     Officer Jeff Kreutzer of the Golden (Colorado) Police Department says he and his four-officer traffic unit have seen a rise in rear-end collisions on high-speed, four-lane highways with traffic lights in Golden and the surrounding area. "We're seeing a lot of [rear-end] collisions at those traffic lights because people aren't paying attention to whether or not they're too close to the front car," Kreutzer says. "The rear-end collisions have tripled roughly over the last four years."

     Golden's police department recently acquired an LTI UltraLyte 100 LR laser equipped with the DBC capability. In the DBC mode, the traffic officer aims the UltraLyte speed laser at the lead vehicle and takes his first measurement. The speed of the first vehicle is displayed on the LCD and in the scope. The laser then measures the second (trailing) vehicle. When the officer has taken the second measurement, the laser will display the speed of the second vehicle and the time between vehicles in seconds.

     Kreutzer reports his traffic unit is targeting the jurisdiction's accident-prone areas more heavily with DBC versus an open stretch of highway. Thus, vehicles inbound to traffic lights and merged lanes are the unit's main targets.

     "We're looking for a consistent distance [between vehicles] for 1/4 to 1/2 mile," explains Kreutzer. "I'm able to take two readings [with the laser] within that interval. The first reading will just be a time interval between them, and in the second one I'll have all the data," he adds. "[The laser] just confirms what we're seeing and that it wasn't just a moment in time."

     Other tailgate-detection products are offered, although availability in the United States may be limited.

     For example, Israeli company Driver Safety Systems (DSS) offers the Marom Traffic Law Enforcement System, which measures a vehicle's speed and detects tailgating. This front-end system observes traffic via two invisible infrared beams across a traffic lane with two retro-reflectors mounted in the road surface from a field unit mounted at the roadside or on a bridge. Each vehicle passing between the electro-optic head and retro-reflectors breaks the two beams and triggers the unit's computer to measure speed, acceleration, headway and vehicle length.

     The Marom system records a digital image of all vehicles exceeding pre-set limits.

     A German firm, Vidit, has a system that makes it possible to analyze precisely timed live video recordings of suspected tailgating by using clearly defined road sector measurements. Distances between vehicles can be calculated at the speed they were traveling and police officers can decide, on the basis of court-accepted evidence, whether or not an offense has been committed.

     Sgt. Eric Hansen of the Grand Prairie (Texas) Police Department would agree with Harsha. In one part of Texas, he divulges, drivers are allowed to drive up to 85 mph.

     "We know that following too closely had been a factor in many collisions," Hansen says. "In fact, 11 percent of all crashes in Grand Prairie in 2006 were tied to following too closely."

     Like so many police departments nationwide, Grand Prairie has wrestled with observing tailgating abuse, yet feels hamstrung with inability to prove it. "We're trying to catch the people that are driving aggressively but have not yet caused a collision to occur," Hansen explains.

     To ensure tailgating is tackled, an agency need not only observe and cite the violators, but it must be sure the court system will allow the evidence. For this reason Hansen took the extra step of orienting his local legal arm on the DBC's capabilities.

     Apparently, the interest in DBC was infectious. Hansen reveals that soon after the demonstration, word spread about the legal system's satisfaction with the device and other Texas agencies visited Grand Prairie and observed the DBC laser, with one agency investing in its own device.

     So, is the DBC helping to put the brakes on tailgaters? Only time will tell. After all, Hansen points out, this technology must be used on a wider basis, and the public must become more knowledgeable about it before DBC will make people afraid of being caught for tailgating. Meanwhile Grand Prairie PD seems to be off to a good start.

     "We've used the DBC since May 2007," Hansen offers. "Only one case has gone to court."

     Bob Galvin is an Oregon-based freelance writer specializing in law enforcement and public safety topics. He can be reached at [email protected].