It's on the fender, inside the cab, holding onto a grab bar or any place someone else might catch a ride. Riders are not safe on tractors. They can be bumped off during a rough ride, or crushed, run over or impaled in an overturn or accident. An enclosed cab can't protect passengers, either. There are numerous reports of accidents in which passengers fall out of the cab and are run over by the tractor.
Riders also can block the operator's vision or become a distraction.
Newer-model tractors are designed to protect only the operator, not passengers, when the tractor overturns. Avoid situations in which others need tractor rides to a field or remote work area. Use a truck or car to haul passengers. Remember that tractors are designed for work, not recreation. If visitors or children want to see a tractor, always turn off the engine before they approach the equipment.