One of the first questions a good DUI defense lawyer asks while defending a drunk driving charge is: what are the bad facts I can get suppressed? For example, if I can convince the judge to suppress that .178 breath test, then the breath test won't be used as evidence against my client at trial.
One of the legal analyses to make as the defending attorney is whether what the officer did after the traffic stop exceeded the scope of what they were legally entitled to do. For example, if you were stopped for a speeding ticket, the officer can only detain you for the reasonable time to conclude a speeding ticket violation. However, if the officer gains probable cause after the stop, he is allowed to expand the stop and conduct further investigation. In 2011, the Kansas Supreme Court addressed this issue again in State v. Coleman. It readdressed legal issues decided years ago. In the 1997 Supreme Court decision of US vs Elliott, the Court decided that during a routine traffic stop, a law enforcement officer may request a driver's license, proof of insurance, proof of vehicle registration, run a computer search of the driver, and issue the ticket. However, the officer can go beyond those basic things IF there is an objectively
reasonable and articulable suspicion that criminal activity was or is taking place. That's what the Kansas Supreme Court said in 2011 in the State v. Thomas case.
In other words, if you were stopped for speeding, the officer can conduct those basic things stated above. If he then detains you longer, without sufficient probable cause, any drugs, or otherwise found in your car should be suppressed. A good criminal defense lawyer should likely be able to persuade the judge.