Final answer:
The minimum permissible height for a saw-horse type barricade used to direct traffic varies according to the specific Safety Standards referred to; without the exact regulations, the question cannot be answered definitively. Barricades must be high enough to be seen by drivers to ensure safety.
Step-by-step explanation:
The question regarding the minimum permissible height for a saw-horse type barricade used to direct traffic is not directly answerable without referencing the specific Part 22 of the Safety Standards referred to. Safety standards can vary by jurisdiction and organization, so the exact requirements could differ based on the applicable regulations.
However, generally speaking, when considering the safety of pedestrians and drivers, the height of a saw-horse type barricade usually needs to be visible enough to alert traffic from a reasonable distance. This would typically be at the eye level of a driver to ensure visibility.
When evaluating how far away a car must be before it might be safe to cross, the distance can be expressed in car-lengths, where one car-length is approximately 15 to 20 feet. A safe distance would allow enough time for a pedestrian to perceive the vehicle, calculate its speed, and make a safe crossing decision. It may range anywhere from 3 to 6 car-lengths in urban environments with lower speed limits, to more than that on highways or in higher speed areas.