Final answer:
The shared left turn lane on certain multi-lane highways can be used to facilitate turning left onto or from the main road, providing a safe space for vehicles to wait.
Step-by-step explanation:
The shared left turn lane on certain multi-lane highways can be used to facilitate turning left onto or from the main road. It provides a safe space for vehicles to wait before making the turn, separating them from through traffic. This prevents congestion and reduces the risk of accidents.