A first conviction for commercial driving under the influence (DUI) typically leads to significant penalties due to the serious nature of operating a commercial vehicle while impaired. The correct answer reflects that a first conviction results in the driver's license being suspended for one year. This substantial penalty is designed to ensure safety on the roads, especially when commercial vehicles are involved, as they often weigh more and can cause greater harm in the event of an accident.
The one-year suspension underscores the importance of preventing individuals with a DUI conviction from operating these vehicles in the interests of public safety. This lengthier penalty compared to standard DUI penalties aligns with the notion that professionals responsible for transporting goods or passengers must adhere to higher standards of safety.
In contrast, the other options suggest either shorter suspensions or no penalties at all, which do not align with the legal framework surrounding DUIs in commercial driving contexts. A 90-day suspension might seem plausible, but it does not reflect the severity typically applied in cases of DUI for commercial drivers. Permanent revocation would be excessive for a first offense. Lastly, having no penalties contradicts the legal implications of being convicted for driving under the influence.