If a gas leak is suspected in the cargo area during transit, what is the correct safety precaution regarding bystanders?

1. Assemble bystanders close to the vehicle to search for the leak
2. Keep public and bystanders away, stay upwind, and prevent them from entering low-lying areas or closed spaces
3. Tell bystanders to light matches to see if the gas is flammable
4. Order bystanders to push the vehicle off the road