State rules or regulations that require 24 hour maintenance of temporary traffic warning devices along highway work zones

From Missouri DOT’s specifications relating to the installation, inspection and maintenance of temporary traffic control devices:
“616.3.2.6 All traffic control devices shall be inspected at least daily with the following exceptions:
(a) Non-portable construction signs and pavement markings on sections of the project with no project imposed speed limit restrictions shall be inspected at least weekly.
(b) Portable construction signs, including cones, flashing arrows and channelizers used with the signs, shall be inspected a minimum of two times each day. The interval between inspections shall not exceed six hours during active work.
(c) Traffic control devices in the work zone shall be reinspected after finding any physical evidence or other information suggesting an accident has occurred in the work zone.”
More details are available at the web site below.