You must be able to hear the back-up warning signal of a vehicle from at least 10 metres away.
200 feet
200 ft
http://wiki.answers.com/Q/A_horn_must_be_loud_enough_to_hear_within_how_many_feet"
200 feet
If your vehicle must have a horn that can be heard from a distance, it is essential to ensure that the horn complies with local regulations regarding sound levels and safety. The horn should be loud enough to alert pedestrians and other drivers without being excessively noisy, which could lead to noise pollution. Regular maintenance is also crucial to ensure the horn functions properly and reliably when needed. Consider choosing a horn that offers a clear, distinctive sound to effectively convey your presence on the road.
If your vehicle must have a horn that can be heard from a distance of 400 feet, it is essential to ensure that the horn meets the required sound level and specifications for safety compliance. You may need to invest in a high-decibel horn designed for visibility and alerting others while driving. Additionally, regular maintenance and testing of the horn's functionality are crucial to ensure it operates effectively when needed. Compliance with local regulations regarding horn sound levels is also important.
Must be able to track the vehicle's location
No one being able to hear them scream.
All instruments you can see and hear, provided you have the ability. In order for it to be an instrument, it must be able to produce sound.
1000 feet
A whistle or horn