Chain of ideas - when it rains, it pours

Why heavy rain causes heavy traffic?

1. People tend to use their private vehicles to avoid getting wet.
2. Heavy rains lessen visibility so vehicles move slower as the drivers become more cautious.
3. There is roadwork up ahead and it does not matter if it rains or not, traffic will remain heavy.
4. An accident has occurred because the driver was too shy to use #2 as an excuse.
5. Rain flood covers the pot holes so drivers move slower to lessen the damage it may cause on the vehicle.
6. Rain floods the streets slowing down traffic.
7. People do not have money for a full car wash so they bring their vehicles our to get "washed" by the rain.