Yes, in the state of Wisconsin, all passengers, including backseat passengers, are required by law to wear a seatbelt while the vehicle is in motion. 
We pursue compensation on behalf on those seriously injured in car accidents every single day. We, as Wisconsin personal injury lawyers are all too familiar with the injuries passengers sustain in car accidents. We frequently and successfully get compensation for passengers in car accidents.
One of the questions we often received involves whether a passenger, who was not wearing a seatbelt at the time of the crash, can still pursue a personal injury case. The answer to this question is yes- an unbelted passenger can still pursue a personal injury lawsuit. In certain situations, there might be a reduction in recoverable damages under Wisconsin law if several factors are proven.
Below we have spent some additional time discussing Wisconsin law as it related to backseat passengers wearing seatbelts.
The simple fact is that seatbelts save lives. According to the National Highway and Traffic Safety Administration, seat belts saved 13,941 lives in 2015 alone. 
In the event of a car crash, a seatbelt can help prevent serious injury or death by keeping the passenger securely in their seat and potentially preventing them from being thrown around the vehicle or ejected.
Additionally, seatbelts are designed to spread the force of impact across the stronger parts of the body, such as the hips and chest, which can help reduce the risk of injury.
Most seatbelts have been tested for years and designed to save lives. There are some instances where a seatbelt may theoretically exacerbate injuries but this is the exception, not the rule. There are also rare situations where a seatbelt may be defective.
It depends on what the officer decides to do. However, by the rule of the law, yes, in Wisconsin, you can get a ticket for not wearing a seatbelt in the backseat. 
According to Wisconsin law, all vehicle occupants, including backseat passengers, are required to wear a seatbelt while the vehicle is in motion. If a law enforcement officer observes a violation, they can issue a citation or ticket, which could result in fines or other penalties.
The use of seat belts is mandatory and is considered a primary enforcement law, meaning a police officer can pull you over for not wearing a seatbelt or not ensuring passengers in your car are wearing a seatbelt.
In Wisconsin, children under the age of 8 years old must be properly secured in a child safety seat or booster seat, according to the Wisconsin Department of Transportation.
A child should be in a safe car seat, booster seat or otherwise that is commensurate with their age and size and in line with manufacturer and legal recommendations.
The tickets and fines associated with breaking child safety laws are much steeper than seat belt violations. If the children involved are less than 4 years old, the total penalty is $175.30, and if they are 4-8, the penalty is $150.10, with that number increasing after multiple offenses.
Backseat seat belts are generally considered safe when used properly. In fact, wearing a seatbelt in the back seat can greatly reduce the risk of injury or death in the event of a crash.
According to the National Highway Traffic Safety Administration (NHTSA), seat belts are the most effective way to prevent death and serious injury in a crash, and the use of seat belts in the back seat can reduce the risk of injury by 75% for passengers under the age of 13.
Ensure the seat belt is properly adjusted and worn correctly in order to provide maximum protection.
In some cases, seat belts can cause injuries if they are not used properly or if the passenger is not properly secured. Based on the data, however, wearing a seatbelt is generally much safer than not wearing one.
It's vital that you ensure the seat belt is properly adjusted and worn correctly, and that children are properly secured in a child safety seat, booster seat, or seatbelt according to Wisconsin laws as well as the manufacturer recommendations.
In Wisconsin, backseat passengers, and children should be secured in accordance with the law when a vehicle is in motion. Fines can be issued by officers who spot a violation of this law.