Once again, Matt Gutman. Reporter: North Carolina's home to some of NASCAR's fastest drivers. But this isn't the Charlotte motor speedway. It's a stretch of I-40 near downtown Raleigh, where "20/20"... See More
Once again, Matt Gutman. Reporter: North Carolina's home to some of NASCAR's fastest drivers. But this isn't the Charlotte motor speedway. It's a stretch of I-40 near downtown Raleigh, where "20/20" will turn the tables on the cops by setting up our very own speed trap. We're going to be along this road. The objective? Follow speeding cops to their final destinations and get some answers. We deploy our surveillance team, starting with Ron Carr. Remember, he's the guy who's been documenting speeding cops in Raleigh for months now. His job is to alert us of any fast-moving squad cars heading our way. White dodge charger, left lane. Actually he's running hot. Reporter: To accurately measure how fast any suspected speeding cops are traveling -- Three, two, one, mark. Reporter: We set up two checkpoints. Three, two, one, mark. Reporter: The plan is, if we confirm cops are speeding, we'll spring our trap, deploying my chase car to tail them to wherever they're going. Even though we chose something with some hefty horsepower, we don't want to get busted for speeding ourselves. So in case we lose them, we brought in the air cavalry, a "20/20" helicopter equipped with an aerial surveillance camera. Those cops can run, but they can't hide from your eye in the sky. The "20/20" speed trap is set, and it's not long till this cruiser flies by our checkpoints at 75 miles per hour. Mark. Reporter: That's ten over the limit. No lights, no sirens. By the time the cruiser reaches us in the chase car, we estimate it's picked up even more speed. It's going at about 85. It's hard to catch up. My chase car is left in the dust, but luckily our chopper team gets us right back on track. The chopper is on it. It says sv crime lab. We're able to follow the car to its final destination and confront the lead-footed driver. I'm Matt Gutman from ABC news. How you been? I'm good. Reporter: Good. We were watching you on I-40. Okay. Reporter: You were going about 85 miles an hour. I'm wondering, what you think about that? I don't really have a comment. Reporter: You don't have a comment? No. Reporter: It's hardly an emergency. The officer is just dropping off evidence at the state crime lab. Don't you think it's a little hypocritical that police officers go 85 miles an hour and they would clearly pull someone like me over? That would upset people. Is that what you're supposed to do? To some extent, serve as an example as how people should drive? Thank you. Standby, this guy's moving. Reporter: Astonishingly, the cops kept coming. Zooming by us, smashing speed laws to take care of non-emergency business, like this sheriff's deputy who hits 82 miles per hour. That's 20 over the limit. We're able to follow the deputy all the way downtown, where we discover there was no emergency. She was just apparently late for an appointment at the courthouse. She is pulling into the official intake vehicles only. We can't do that. Same story with another sheriff's vehicle that we clock at 82 miles per hour. He's going so fast. He was going 82. Stay on him. Chopper stay on him. Everybody stay on him. Reporter: He's moving too fast for me to keep up with. Oh man, I lost him. Fortunately, our trusty chopper again comes to the rescue and puts us back on his tail. The officer leads us on a merry slow speed chase through Raleigh's downtown streets. I think he's trying to shake us. He finally comes to a stop at the federal courthouse. We're from ABC news. We noticed that, on I-40 over there, you were going 82, 85, wondering if you were on an emergency call. We didn't see the flashers. I'm here to pick up a federal prisoner. Take him back to edgecombe county. Reporter: I know if I went 81 or 82 you'd probably pull me over. I would. Reporter: Do you think your superior would mind that you were going that fast? Would he mind? Probably. Three, two, one, mark. Reporter: But not all of the cops we caught speeding were on official business. Check out this officer cruising by at 79 miles per hour. Our helicopter crew tracks him as he exits the highway and follows him to, you're not going to believe this, a doughnut shop! And Dunkin' donuts wasn't the only eye-opening destination we discovered over the course of our surveillance op. Mark. Reporter: Check out this highway patrol SUV speeding at 75 miles per hour. I see him! By the time he gets to us in the chase car, we estimate he's going even faster. So this guy's going well over 80 right now. Tearing across lanes just to get to his exit. Wow, he did three lanes at once. He just did three lanes without using his blinkers, ladies and gentlemen. We're able to catch up on a local road, but again he punches the accelerator. You guys, this guy's going 70 in a 45 right now. We finally find out where that trooper was headed in such an all-fire hurry. Incredibly, he was speeding just to get to the highway patrol training academy. This place even has its own driver's training course. So we're doing a story about speeding cops. And we noticed you were going about 80 miles an hour on the highway and then about 75 in a 45. We had a hard time keeping up with you. Yeah, I was trying to get over here this morning. That, you know, police officers speeding, a lot of folks want to see you set an example and you're going about 15, 20 miles over the speed limit, there might be some concern. I understand what you're saying. Reporter: If you're wondering what subject this officer teaches here, take a look at his shirt. Yep, that's right. He's a driving instructor. Gentlemen, how are you? Time to get some answers. We walk into the training academy with cameras rolling. Let me -- can you just step inside? Reporter: Sure. But none of the supervisors on-site are willing to talk. You're not even curious about what your guys are doing, the guys who are speeding to get here? Sir, I'm not even at liberty to discuss this with you. Reporter: Later, after we've left North Carolina, a spokesman for the highway patrol tells us they've launched an investigation into what we found. We went ahead and started looking into this matter and we're going to handle it accordingly. Reporter: Do you find it outrageous that one of the people we found driving most recklessly seemed to be a driving instructor? That's not a good thing. It kind of paints the wrong type of message. We are dealing with that individual. Reporter: But in Connecticut, what we found during our surveillance operation came as no surprise to the families of teenagers Ashlie Krakowski and David Servin, who lost their lives because of a speeding cop. It could be anybody's kid. Anybody's child. And it's the worst thing that could ever happen to you. Our hearts go out to both of those families. Have you seen speeding police officers? Let us know on Twitter. David and I will be right back.
This transcript has been automatically generated and may not be 100% accurate.