To drive safely in **snow or ice** conditions, it is crucial that the tires have a good grip on the road. This is because both snow and ice significantly reduce tire traction, which can cause the vehicle to skid and require more space to brake.

- **Tires with rounded-edge studs**: These studs are specially designed to improve tire grip on slippery surfaces like snow and ice. Rounded-edge studs provide additional traction without excessively damaging the road surface, making them ideal for these conditions.

- In contrast, **sharp-edged studs** or **special car tacks** are not recommended. Sharp-edged studs can damage the road and do not offer the same level of safety and stability as rounded-edge studs. Tacks are not suitable for this purpose and are not designed to improve traction in snow or ice conditions.

Therefore, to ensure safe driving in snow or ice conditions, it is essential to use tires with **rounded-edge studs**.