I used to work in sales for a manufacturer of a piezo sensor that is placed in the road surface and can WIM (weigh-in-motion) a vehicle traveling at highway speeds (i.e. 70mph) and be within 5% of actual weight. Some places they have them installed in the highway approaching a scale and can be able to tell whether a truck is near max weight before it gets to the actual scale and either give it a green light or a red light. They watch for van trailers as they can't see if they are loaded or not, not the case with flat beds or low boys. I sold these in nearly very state (as well as South America), Texas DOT was my biggest customer. I helped install one on I-10 west of San Antonio and also one on a state highway in Missouri at the Kansas state line. They also place the sensor in many areas where there are no scales but do traffic studies and be able to tell when there may be an elevated amount of overweight traffic, such as in the Midwest at corn harvest time and bring out the portable scales. They can also classify traffic and count how many cars, trucks, motorcycles are using the highway and measure speed. The information is stored on a hard drive at the site and polled via an installed cell phone. For those of you that are commercial drivers, big brother is watching you when you don't even realize it.
2014 Palomino Puma 25RS
2011 F-150 Super Crew XLT
Days camped in 2014 - 23
Camped 2015 - 47
Camped 2016 - 51 done - 6 more planned so far