Under what condition is it acceptable to drive at a lower speed than the posted limit?

Driving at a lower speed than the posted limit is acceptable in adverse weather conditions. Adverse weather can include rain, snow, fog, ice, or other situations where visibility is reduced or road conditions are slippery. Decreasing your speed in these conditions helps maintain control of your vehicle, increases your reaction time, and reduces the severity of potential accidents.

While it may be advisable to drive at lower speeds in a residential area due to the presence of pedestrians and children, this is typically addressed by speed limits that already account for such conditions rather than being a distinct justification for driving below the posted limit. Listening to music or feeling tired does not provide legitimate reasons for driving below the speed limit, as these factors are more related to driver distraction or fatigue management rather than the impact of external driving conditions.