When driving over high-altitude mountain passes in winter (such as Dochula, Pelela, or Chelela) where frost or 'black ice' may form, how should you handle the vehicle?

1. Drive in the lowest gear at maximum engine revolutions
2. Drive smoothly at reduced speed in a higher gear, avoiding sudden steering, harsh acceleration, or abrupt braking
3. Brake frequently and forcefully to test tire traction on every curve
4. Use cruise control to maintain a steady speed on ice