A vehicle's gross vehicle weight rating is an important number to know, whether you're driving a pickup truck towing a trailer, a two-seater roadster or anything in-between. You can think of the GVWR as a weight limit for your specific vehicle -- a weight limit set by the automaker. Gross vehicle weight ratings take into account the base curb weight of the vehicle plus the weight of any optional accessories, cargo and passengers. A vehicle should never be loaded beyond the manufacturer's listed GVWR.Safety is the driving force behind the GVWR for any vehicle. If a vehicle is overloaded, a number of problems can result. For example, if the vehicle is too heavy, the brakes may not be substantial enough to slow down or stop the vehicle effectively; the suspension components can become ineffective or possibly even break under the added strain and tires that are overloaded generate more heat, making them more likely to blow out. For safety's sake, the GVW should never surpass the GVWR.It's important to understand that a vehicle's GVWR is not a measurement of how much a vehicle actually weighs. A vehicle's actual weight is the gross vehicle weight, or GVW. The two numbers should not be confused -- the GVW of a vehicle is constantly changing, but the GVWR will always remain a constant.As a simple example, if a car has two passengers and one of those passengers exits the car, the GVW is reduced by the exact weight of the exiting passenger; however, the GVWR remains the same. If the same vehicle (with two passengers on board) stops to pick up a third passenger, the GVW is increased by the exact weight of the new passenger, yet once again, the GVWR remains the same.When you're towing a trailer, one last point to remember is that the entire weight of the trailer is not considered to be a part of your vehicle's GVW; however, the tongue weight -- the weight of the part of the trailer that actually attaches to your trailer hitch -- is part of your vehicle's GVW. Again, none of this changes your vehicle's GVWR. Trailers have their own specific gross vehicle weight ratings that, similar to the tow vehicle's GVWR should never be exceeded.If you're curious about your own vehicle's gross vehicle weight rating, that information can typically be found on a label inside the vehicle's door frame, often in the area where the driver's door latches. Another option is to search for the information on the Internet. Most manufacturers will publish this and other important vehicle information online.The chart on the next page may be helpful, too.