Commercial drivers typically face suspensions of no less than one year of CDL privileges when they get a DUI. This rule would apply to your first conviction. For your second conviction, the court would probably ban you for life from getting a CDL.
As mentioned on FindLaw, you could get a longer suspension if you were convicted of impaired driving in a commercial vehicle versus in your own personal vehicle. However, when determining whether you may be liable for a DUI conviction, the law would subject you to higher standards — regardless of which vehicle you were driving. In Illinois, that means a .04 BAC limit as opposed to the non-CDL holder’s .08.
When attempting to fully understand the possible consequences, there are two important functions you should understand. The first is suspension. This means that the court would take away your license temporarily and reinstate it at the end of the suspension period. The second is revocation. When the court revokes your license, you would have to reapply in order to get a new CDL.
Although suspension and revocation very different, there are some similarities. For example, the law would prohibit your employer from retaining you as an employee for the duration of any suspension or revocation period. Also, please keep in mind the law requires you to make a report to your employer of any convictions for traffic violations — in your personal vehicle or in your commercial vehicle.
As you can see, understanding the situation that led to your DUI charges is just one part of your defense. You may also want to consider the state and FMCSA rules, as well as how any formal action could affect your career over the long term.