What is the purpose of an Ignition Interlock Device?

The purpose of an Ignition Interlock Device (IID) is specifically designed to enhance road safety by preventing individuals who have been convicted of driving under the influence (DUI) from operating their vehicles while impaired. The device measures the Blood Alcohol Concentration (BAC) of the driver; if it exceeds a preset limit, typically .02, the device will prevent the engine from starting. This ensures that individuals with a history of alcohol-related offenses do not drive while under the influence, thereby reducing the risk of accidents caused by impaired driving.

In contrast, improving vehicle performance, monitoring speed, or restricting access to certain time periods do not align with the primary function of an IID, which focuses solely on alcohol detection and prevention of impaired driving. This makes option C the correct choice, as it accurately captures the critical safety feature that IIDs provide.