What factors and circumstances should be taken into account when choosing a safe speed for the prevailing road conditions?

According to Art. 19 of the Road Traffic Act, a driver is obliged to drive at a speed that ensures control over the vehicle. In the situation shown in the picture, one must consider the slippery, snow-covered surface, limited visibility due to fog, and the possibility of being dazzled by the sun. Even though the D-43 'End of built-up area' sign raises the speed limit, the prevailing conditions require a significant reduction in speed to maintain safety.