San Diego — At the east end of Otay Mesa, where the business parks and trucking yards give way to open grassland, stands the California Highway Patrol's Otay Mesa Truck Inspection Facility. It's a sort of nouveau-industrial building constructed of concrete and corrugated sheet metal painted in pastel hues. An indication of its newness -- it opened in May of '96 -- is the smallness of the eucalyptus, oleanders, and flowering plums that make up the landscape. Along the west side of the building, a line of trucks rumbles slowly past tinted windows. "Two-thirds of them," says Sergeant Steve Vail, "are from fully Mexico-based companies. The other third are from what are called combo companies. They're based in both Mexico and the U.S. They've got a high enough percentage of trucks that are U.S. based that they can be considered a U.S. company."

Vail is a 25-year CHP veteran who has worked at this facility since December 1995 when it was "a couple of trailers on Enrico Fermi" Drive. A thickly built man of 49 with a gray brush mustache, Vail explains the facility's purpose. "Our primary function," he says from behind a desk in his office, "is to inspect commercial vehicles for mechanical safety violations. We assess driver-impairment to the extent possible and, though it isn't our primary function, we don't close our eyes to drug interdiction. But that's really not an issue for us because before they come here, customs down there X-rays them, works them over with dogs and everything else. But if some elements are there -- odor, or we find a false compartment while inspecting -- then we'll do a little drug interdiction. But that isn't our primary function."

Illegal immigration?

"We don't get into much of that. We've actually had them run across here, but we don't physically arrest them. But if a border patrol is trying to arrest them out there and the fight is on, then the officers will go to their aid. We don't have any come on the trucks. They do get them in cars in different places but not here at the commercial port. You have to sit in line a really long time and they know that most of the trucks get X-rayed and it's really easy to see a body anywhere in the truck. So we don't have too much illegal immigration coming through the commercial gate in the trucks."

All of the 2300 to 2400 trucks -- many of which are repeats -- that come through the inspection facility Monday though Friday are checked for height and weight violations and are at least "eyeballed" for violations. Vail leads me to the area of the office behind the out-leaning, tinted windows. An officer sits there watching the trucks rolling by. Vail explains, "The trucks come into U.S. customs facility down there on Via de Amistad. Once the feds are through working them over, they come out and there are two signs that direct them here. Some days we have a rover making sure they don't try to make a left turn or sneak around. Eventually, they won't have a choice. This road will be finished late this summer and they'll be forced through here. Right now a guy could try to sneak around and some do. Though we can't catch everybody, the rover usually does snake them. If he thinks he was pulling a fast one, then we write them for running the scale. If we think the guy made an honest mistake and missed the sign, then we write them for sign violation. Anyway, they come down Via de Amistad and they are directed to us. They come up here and go through our scale."

Pointing to the curb outside the window, Vail says, "There are two scales between those yellow lines. You can't have more than 20,000 pounds on a single axle. You can't have more than 34,000 on a tandem axle. Then your gross, your whole rig can't come to over 80,000 pounds. We have a beeper for the over 34,000. The 20,000 you have to watch for on the meter."

Vail pats the on-duty officer on the shoulder. "Along with watching for overweight, our sharp-eyed inspector is watching for violations like missing lug nuts, cracks in the rims, bulging tires. You can't tell a whole lot about the tire tread, but you can tell if there are chunks missing or if it's really slick, especially on the steering axle. You can also see loose air hoses, mud flaps missing, wobbly steering, anything that pops out at you. Also, you look at the driver. You look at the rig, of course, but when they're coming by, you look up there.... Like this guy, he's pretty casual, he's checking his mirrors, chances are he's okay. But you might see someone coming in here looking really intense, and they've got a major death grip on the steering wheel and, boy, they won't look you in the eye. Then you might pull them over just to make sure their not impaired."

What happens if you notice something wrong with the truck? Indicating the microphone in front of the officer, Vail answers, "He hits the P.A. system and it comes out the speakers outside, 'Name of the truck, please pull over and park, bring in your paperwork.' That's if he sees a violation or registration. If it's overweight. Then we reweigh them. The officer also looks for the sticker in the lower right-hand corner of the windshield. You look for the number, it will have either eight or nine meaning '98 or '99. The color tells you what quarter of the year. There are four quarters so there are four colors: green, yellow, orange, and white. If two corners of the sticker are gone, it's the first month of the quarter; one corner missing, second month of the quarter; full boat is the last month of the quarter. So by looking at the sticker, we know if their last inspection is still valid or if it's expired and they need a new inspection. For instance, this one coming in has an eight. That means 1998. It's white, which means the last quarter, and it's got all the corners, which means the last month. So the last month of the last quarter; December '98. He's due for a new inspection.

"Transportes Servin...camion azul," says the officer over the P.A. system. The blue truck halts. "Puerta dos, por favor."

The truck driver proceeds forward, but instead of merging to the left onto northbound Enrico Fermi Drive as all of the trucks have been doing, he makes a broad turn to the right and follows cones around the east side of the building and finally into the inspection garage from the south. Vail leads me through the office -- on the way pointing out a South Bay municipal court desk where drivers can pay court fines and a DMV desk where they can pay registration dues -- to the inspection area where the blue truck is being guided into bay number two by one of the inspectors. "There's the guy we were looking at coming in for his inspection. First, the inspector will check the driver, then he'll start the inspection. He'll go over the rig checking critical items: steering, suspension, tires, brakes, the major items that can cause an accident. He puts the information in the computer. From start to finish, it's usually about a half an hour."

If the truck being inspected has no violations, it will receive a new sticker, and unless an officer spots a violation the next time it goes through the scale, it won't be inspected until next quarter. If the inspector finds a minor violation, the driver will be given a warning ticket and sent on his way. If the violation is serious enough, a ticket bearing a $10 fine will be given and, after he pays the fine, the driver will be sent through. The next time either of these first two drivers comes in for his routine quarterly inspection, special attention will be paid to the items he was ordered to fix. If he still hasn't fixed them, he will be given a fine-carrying ticket for disobeying an officer's order.

If an inspector decides a violation meets the out-of-service criteria set by the Commercial Vehicle Safety Alliance (made up of all 50 states, some provinces in Canada, some states in Mexico), "We park them," Vail explains, "and they have to fix it before they go or they've got to get their own big-rig tow, and they can tow it back to Mexico or someplace for repairs. Otherwise, they have to fix it here. If they have their own mechanics, they can come in and fix it. We give them about 48 hours. We figure that's enough time. If they're not trying to effect repairs during that time, we'll tow it out of here. If they come to us and say they've got a part coming, we'll let it sit there. But if two or three days go by and nothing appears to be done, we impound it."

Vail adds, "Our focus is mechanical safety. It used to be mechanical violations caused many accidents, but now the vast majority are caused by driver violations. I think it's because the CHP in California have really invested time, money, and training into making these trucks safe. We hit a lot of trucks not only here at the border but at all the other scale facilities plus our mobile road-enforcement guys. I think that's why the crashes due to mechanical malfunction is low, 3 to 5 percent. The other 95 percent is driver error, because you can't control that."