Final answer:
Drivers must slow down to 70 km/h when approaching a stopped emergency vehicle with flashing lights on highways with speed limits of 80km/h or over, in addition to changing lanes for the safety of roadside emergency personnel.
Step-by-step explanation:
When approaching a stopped emergency vehicle with flashing lights on a highway where the speed limit is 80km/h or over, specific laws require drivers to not only change lanes but also to reduce their speed. While each jurisdiction might have different rules, generally, the speed you must slow down to is 70 km/h. This is in place to ensure the safety of emergency personnel working on or near the highway.
It is important to follow these laws precisely to prevent accidents and to comply with local traffic regulations. Moreover, being aware of how to safely interact with emergency vehicles is a key aspect of being a responsible driver.