It's not the first time the law has been upheld in regards to 'flashing your brights' in the US. In 2005 a similar case reached the courts with identical results.
The issue has continued since, however, with Florida Highway Patrol issuing more than 10,000 tickets for identical offences since 2005.
The Seminole County judge ruled that it is a person's constitutional right to free speech to communicate with other drivers using their headlights.
Warning other road users of speed cameras by flashing your lights is illegal in NSW, deemed an 'undue use of headlights'.