A system includes an impairment sample module, impairment value calculator module, threshold comparison module, warning alert module, and intervention module. The impairment sample module may be configured to obtain a first impairment sample for an operator of a vehicle while the vehicle is running. The impairment value calculator module may be configured to calculate a first impairment value based on the first impairment sample. The threshold comparison module may be configured to compare the first impairment value to a first threshold value corresponding to a first range of impairment and a second threshold value corresponding to a second range of impairment. The warning alert module may be configured to generate a warning alert in response to determining that the first impairment value exceeds the first threshold value. The intervention module may be configured to execute driver intervention protocol if the first impairment value exceeds the second threshold value.