The red triangle, reporting duty, and personal responsibility
Illness, medication, pain and temporary impairments can reduce driving ability in different ways. Some conditions slow reaction time, others impair concentration, balance, vision or judgment. Medicines can cause sleepiness, dizziness or delayed thinking even when used correctly. Having a licence doesn't automatically mean you're fit to drive every day and in every condition.
Medicines that can affect driving ability are marked with a red triangle on the package — that's the Swedish Medical Products Agency's standard marking. Always read the leaflet before driving. If you're obviously unfit to drive due to illness, your doctor may report it to Transportstyrelsen under Körkortslagen ch. 10 §2. It's a protective rule, not a punishment.
You've taken a new allergy or pain medication and notice you feel slower and less focused than usual. You're thinking of driving a short distance. See a red triangle on the box? Then the safest conclusion is that a short trip isn't automatically safe. When fitness is uncertain, the right choice is other transport or waiting until the effect is gone.
A common miss is thinking only severe illness matters. In practice, even mild fever, migraine, emotional shock or new medication can lower attention enough to create risk. The exam often tests whether you choose convenience or safety when your fitness is uncertain.