This sign is at the Laurel scale near Billings, MT. The lower sign says "Prepass Site" indicating that this weigh station is served by PrePass. For the most part, all major scales have PrePass service. There are, however, some in more remote locations that do not, and also a few states that do not participate. Among these are Kentucky and Idaho which have their own version of a prepass type service that truckers can subscribe to. We do not subscribe to those states systems, but we do have PrePass.
About 1/2 to 1/4 mile from the scale there will be a second sign indicating whether or not the scale is open. As you approach a weigh station, if it is open the best and most helpful thing you can do is to move into the left lane and stay there till you are past the weigh station. This is because all trucks are expected to merge into the right lane well before the station, and also it helps trucks re-enter the roadway and get their speed up without having to worry about where you are.
Do you see the PrePass sign? Its the big white one. It says "Follow In-Cab Signal." Drivers with PrePass have a device on their windshield that looks something like this.
Now lets go back to this picture.
Most often, but not always, there is a scale in the road beneath the first sensor. Look closely next time you drive past one. You can see it there in the lane. As the truck with PrePass drives over the scale, and under the first sensor, the sensor reads the box in the window, identifies the truck, reads the weight, and transfers the weight and truck information to a computer in the scale house. Now at this point I'm not sure if a person looks at it and decides or if the computer makes the choice, but the decision is made as to whether or not the truck must enter the station. As the truck runs under the second sensor, it transmits a signal to the box in the windshield of the truck.
If the green light flashes and beeps at you, you are free to proceed past the scale and continue down the road. However, if you get a red light, you must enter the scale and be weighed. (the center light is yellow...I think it means the batteries low, but I'm not sure)
This particular day, Laurel had their PrePass turned off. Thanks a bunch! So in we go!
On those days when you do get PrePassed, there is a third sensor in front of the weigh station. I beleive this one registers that you passed the scale. We pay a monthly set fee of $16 for the service, but when we were with Prime, we payed per pass. So everytime we got a green light, we were charged a certain amount, I think it was like a dollar or something. And I think its this sensor that transmits that information, but I'm not sure exactly.
Once you have entered the scale, there is a set speed limit you are supposed to slow down to. Some scales have a bypass lane within their drive, and a scale in the road as you approach the main scale. If you are going to correct speed and they are satisfied with your weight, they might bypass you in this lane and you can skip back out to the road. If not, then you are to drive up to the scale in front of the scale house. Some states require that you come to a stop before moving onto the scale. Others want the flow of traffic to continue at around 5mph or so.
So the strategy here is to not be the truck in front, or in back, and to certainly not be the only truck on the road that morning as we were. The reasoning here is that probably the guys bored and will look closer. Whats perfect is to pull in just ahead of or behind a wide load or something really odd thats probably going to be checked closely. What's not cool is to be female, modestly attractive, and driving past a bored scale house. I can't tell you how many times I got pulled into Laurel when we first started here. They'd send Malcolm on his way everytime, but if I was driving they'd check my paperwork. Come to think of it, several scales were like that for a while. I must just be a middle aged truck driving woman now, because on the occasion that we don't get Prepassed, I don't get pulled in to "visit" much. I'm not sure if I should be glad of that, or insulted.
Anyway, I got off track there. So here we are approaching the scale house. Sometimes they roll you straight across the scale. Sometimes they stop you on each axle and weigh them seperatly. There are laws regarding how much weight can be on each axle. Some scales are really predicatable. Laurel is ALWAYS open 24/7 but hardly ever weighs our axles. Belgrade, MT is closed late at night, but ALWAYS weighs every axle, at least on us. Idaho is unpredicatble going south, but going north they are garuanteed to be open by 6:00am. Utah, almost always open, but almost always prepasses us. California....lets not go there. Wyoming has ports of entry and with livestock we are required to stop. We have to tell them what we have, where we're going, and how many head. But with reefer we can use the prepass system if it goes off. However, they generally stop everone and generally everone goes in and has to show registration and IFTA license, but they are generally really friendly too and its more or less just a time hassle.
Here is the light at Laurel at the scale. If it turns red you are supposed to stop so they can weigh your axle. Green, you move to the next one. If it flashes you have to park and bring in your paperwork.
At a weigh station, the point is not just to weigh you. As your rolling onto their scale they are reading your DOT number off your truck and putting it in their computer. This registers that you were there at that time, so that later down the road, if they check your logs for some reason, and it doesn't reflect that you were at the Laurel scale at 9:30 Sunday morning, they know your falsifying your logs. Also, it pulls up your safety rating and lets them know what kind of record you have as far as accidents, speeding, how past inspections have gone, etc. If you have a bad report, they are going to look more closely at your equipment and paperwork. If a good report is present they are more likely to pass you on. They are also looking at your equipment as you roll by and if anything is amiss or looks bad, they can pull you in a do a full inspection on it. Some weigh stations even have seperate facilities that look like giant garages. This is the dreaded inspection bay where they go over your truck and trailer with a fine tooth comb. We've been inspected like this a couple times. Always pass with flying colors of course. But some are put out of service till tires are replaced, brakes fixed, leaking air lines taken care of etc. If your logs are out of whack, you can also be put out of service for that, which means you get to park there for 10 hours or more till you're logs are back to being legal. Generally a 10 hour break is required I think. I, fortunatly, wouldn't know for sure.
Weight stations have reputations. For instance the one west of Rapid City, SD on I-90 is notorious for being nit-picky. In fact all SD scales, when open, are not pleasant to visit, but they are also hardly ever open. Wyoming is very layed back. Montana can go either way, but Laurel doesn't have a good rep. I havn't heard much about Idaho, but I can say we've had to re-power (which means swap loads) with one of Steve's drivers who was shut down at the Utah port of entry for being over his log hours. And California....lets not go there. It would be ok with me if we never went there. I'm sure you know from general news stories that California is picky and difficult about everyday stuff, so you can imagine the trouble they put drivers through. We even have to have a specific length trailer to go there, and we can't idle our trucks, and ....wait...I think I have another Trucking 101 here.
So there you go, weigh stations in a not so little nut shell. Its more complicated than this in some ways, but its not worth trying to explain it all to you in that much detail. Like I said, take a look next time you go by one and you'll see the "parts" I mentioned in this article. Also, remember to move to the left lane when you see that sign. It helps us a lot.And if you are in an RV, don't use the shoulder of a weigh station exit ramp to fix a flat. And FYI, if you are driving a U-Haul or such type vehicle, technically, your supposed to enter the weigh station too.
( On RARE occasions, like in Crow Agency, MT the scale is in the center of the interstate and serves both east and west bound, so you need to merge right. Your smart...you can figure it out for yourself.)
For more reading on PrePass: