On **two-way roads with two lanes in each direction**, you must drive in the **right lane**. The **left lane** is specifically used for **overtaking** other vehicles. This means that if you need to pass a slower vehicle in front of you, you can use the left lane to do so and then return to the right lane.

- **You should not constantly drive in the left lane**. This lane is not intended for driving the entire route, but only for performing overtaking maneuvers.

- On two-way roads with **three lanes**, the center lane can also be used for overtaking, but the left lane should never be occupied for continuous driving.


Therefore, on a two-way road with two lanes in each direction, the correct use of the left lane is for overtaking, thus ensuring a safer and more efficient traffic flow.