A new challenge that comes with weed being legal in Illinois is catching people who are driving high. The police will issue a sobriety test to see if you are driving under the influence.
There are many tests that include walk and turn, lack of convergence, and modified romberg test, and having someone determine when 30 seconds is up. Someone that is high will take about a minute for them to determine when 30 seconds is up.
If you are caught driving under the influence of cannabis it will be the same punishment if you were caught drunk driving. After the suspension of your license, court fees, and other fines it will be around $16,000.