When two vehicles meet on a narrow road section marked with signs 1.13 ('Steep Descent') and 1.14 ('Steep Ascent') where an obstacle is present, who has priority?

1. The driver moving uphill (on the ascent) has right of way, and the driver moving downhill (on the descent) must yield
2. The vehicle moving downhill always has priority
3. The heavier vehicle always has priority
4. Whichever driver reaches the obstacle first