Final answer:
You must slow down when approaching a stopped emergency vehicle with flashing lights on highways with speed limits under 80km/h. The required slowed speed typically could be 70 km/h or lower, depending on local traffic laws.
Step-by-step explanation:
When approaching a stopped emergency vehicle with flashing lights on highways with speed limits of under 80km/h, you must not only change lanes but also slow down to ensure the safety of emergency responders. In most jurisdictions, the required speed to which you should slow down is 70 km/h or the posted speed limit, whichever is lower. In some places, specific rules may dictate a different reduced speed, such as 60 km/h or 40 km/h. However, without a definitive location or context provided in the question, it's challenging to give a specific answer, as the laws vary by region. It is vital to check local traffic laws to understand the exact requirements.