Legal Question in Civil Rights Law in Illinois

Your fact pattern is a little unclear. What was the original probable cause for the stop? Was there probable cause? If yes, and if police observe nystgmus or smell alcohol, that is then PC to probe into the offense of dwi or dui. Though nystagmus can be explained by certain medical conditions and does not always mean a driver is impaired/drunk, the series of events that follow from here are important to be analyzed on a case by case basis. Did police officer request voluntary roadside tests? If so and if driver agreed, and that gave the officer further probable cause to think the driver is impaired/drunk, then a subsequent test to make such determination is supportable under the Fourth Amendment.

If you are being charged with a DUI you need to hire an attorney.