Which of the following is illegal to operate in a vehicle?

Operating a device that generates excessive sounds is illegal because it can create a disturbance and distract other drivers, leading to dangerous driving conditions. This aligns with noise regulations that many jurisdictions enforce to maintain public order and safety. Additionally, if a sound-producing device can be heard from a distance of 100 feet, it typically exceeds acceptable sound levels for a vehicle, indicating that it is likely considered excessive and bothersome to others. Both scenarios contribute to noise pollution and can ultimately impair the driving experience not only for the driver but also for pedestrians and other road users. Thus, both conditions outlined in the question illustrate reasons why such devices would be illegal in a vehicle context.