Final answer:
A passive highway-rail crossing is a type of crossing where the road and railway intersect without any warning signals or gates. Drivers need to be extra cautious at this type of crossing because there are no automatic safety measures in place to prevent accidents.
Step-by-step explanation:
A passive highway-rail crossing is a type of crossing where the road and railway intersect without any warning signals or gates to control traffic. These crossings rely on drivers to stop and look for oncoming trains before proceeding. It is important to be extra cautious at this type of crossing because there are no automatic safety measures in place to prevent accidents. Drivers need to be vigilant and attentive to ensure they do not collide with trains.