What is the final step a traffic control supervisor must perform before opening a newly installed temporary traffic control zone to live traffic?

1. Collect all spare sandbags and store them inside the buffer space.
2. Disassemble the advance warning signs to prepare for quick teardown.
3. Turn off all arrow boards and PCMS displays to conserve battery power before leaving the site overnight.
4. Drive through the entire setup at prevailing traffic speed to inspect visibility and alignment.