ACE Checkzone: The Analysis Zone double-click video to start, click to pause. This clip shows a camera's eye view of cars passing through the Analysis Zone. Between the vehicles you can make out other cameras across the road. The drivers are at first unaware of the cameras so traffic flow is unaffected. As the enemy figure out their presence and function, they begin to take steps to avoid them. In this clip you can observe one of these tactics -- hiding behind larger vehicles. double-click video to start, click to pause. This clip shows another way the enemy can obscure their actions or their presence: operating during low-visibility conditions like fog and rain. In these conditions, light-colored vehicles blend in very easily and the contrast is reduced between dark vehicles and the road surface. Also, it is even more difficult to detect vehicles hiding behind other vehicles. Videos require Quicktime. Narrative Four sensors are set up on the ground to face oncoming traffic, two on each side. These units are small and almost undetectable by moving vehicles, so there is no traffic impedance. Soldiers away from the cameras are watching monitors which record the size, weight and style of vehicles as they approach. In the early morning hours, traffic is slow, averaging about 1-2 vehicles per 5 minutes. During this time, every vehicle that passes through the Analysis Zone is recorded and logged. As the morning wears on, traffic steadily begins to increase as people begin their morning commute. Soon, it is no longer possible for the sensors to gather data on every vehicle as they pass. Using their experience as a basis, soldiers direct the sensors to monitor the vehicles they think are the most likely to pose a threat. Over the next 30 minutes, 40 vehicles are analyzed. The soldier in charge of monitoring the sensor feedback noticed that 2 of those vehicles differed in average weight (as compared to typical weights for similar vehicles on the same roadway); one weighing 1500lbs over the average and another one 900lbs under the average. Also, 3 vehicles were found to have abnormally distributed weights which differed significantly from what the soldiers had been used to seeing. These vehicles were 'marked' in a database with identifying information (make, model, color, etc) to alert operators at Zones 2 and 3 that these vehicles are considered to be an increased risk. These methods worked remarkably well until for about 1-2 weeks. Numerous cars were flagged and this information proved useful in stopping and checking vehicles in the Enforcement Zone, as well as directing questions for soldiers to ask when the vehicles enter the Confrontation Zone. But the enemy soon realized the questions they were being asked about their payload and intentions meant that somehow data was being collected before they arrived (in the Confrontation Zone). Over this time it appeared the instances of vehicles flagged from the Analysis Zone had declined. It was discovered that the enemy had noticed the cameras and were employing various strategies to hide from them. These included operating in low-visibility conditions, and even attempting to hide during increased traffic by surrounding themselves with other vehicles. In response to this, soldiers placed camouflage over the cameras and moved the cameras routinely to better hide them. Additionally, because the enemy had not yet figured out that vehicles were being assessed based on weight, increased vigilance and scrutiny during times of increased likelihood of deception was an effective means of mitigating this threat, however it's clear that at some point the enemy will figure this out, and this will require a further adaptation from the soldiers to maintain effectiveness.