Every road has a weight limit. The limits may vary depending on the characteristics of the road. The design is usually fine for passenger vehicles, but larger trucks and commercial vehicles have to be aware of how much their vehicle weighs so they can safely travel.
Trucks carrying loads will go through weigh stations to make sure they are not overloaded. Running a truck overloaded is dangerous and illegal. North Dixie Truck & Trailer, Inc. explains an overloaded truck represents a hazard on the road as they increase the chances of an accident.
Reasons it is dangerous
A large truck already requires extra time to maneuver and stop. If it runs overloaded, it requires even more time, which means there is an increased chance it will lead to an accident. Another issue is a truck already weighs far more than passenger vehicles. In an accident, an overloaded truck will lead to more damage and more potential for fatalities.
Extra weight on a truck also leads to more damage to the vehicle. It can cause tires to wear faster and increases the risks of a blowout. That in turn can increase rollover risks or cause the driver to lose control.
While many highways and interstates have weigh stations requiring trucks to weigh and come in under the limit, some truck drivers try to bypass or cheat the system. There are tricks they may use. The reason they do this is some drivers get paid by the load. The more they carry, the more they can earn. For others, being able to move more freight means they get done with the job quicker. It all comes down to taking the risk for money, which is dangerous.
There is no way for anyone but the truck driver to ensure they do not run overloaded. Unfortunately, everyone on the road could suffer if they decide to make their truck heavy.