When calling the 122 traffic police emergency hotline after an expressway collision, what critical location information must the caller report?

1. The color of the sky and ambient wind direction
2. The expressway name/number (e.g., G42), traveling direction (e.g., toward Chengdu), and the exact kilometer stake and 100-meter marker numbers (公里桩和百米桩号)
3. The license plate numbers of all passing vehicles
4. The brand of the driver's mobile phone