There are many warning systems in place to control crowds and one of the tools used is hazard tape. You may have seen these used in construction sites warning people to keep away. They are also used when there has been an accident or if there is a police scene. Even certain big events tend to have hazard tape to create a barrier.
There has to be a perimeter set up around a certain area before you start putting hazard or barrier tape. There has to be a risk assessment carried out for this cordoned off area to ensure that the public cannot enter it. If the hazard tape is installed incorrectly, it can be a tripping hazard. Also, there has to be a certain distance between the crowd and the tape for it to prevent from becoming a tripping hazard and this has a lot to do with the initial risk assessment and perimeter determination.

The most common hazard tape color we have seen is yellow. There are red hazard tapes as well. Red is used to denote medium or high danger levels. So whenever there is a threat to life, red tape is used. You will need to enter the area with a supervisor or somebody who is cleared to guide you through the area. Some of the areas where red tape is used are overhead hazards and small cramped areas.
The yellow hazard tape denotes caution. While safety is low in the area that is denoted by the yellow tape, the hazard is not considered a threat to life. These are generally used in cramped working quarters. For example, if there is a repair on the road or maintenance, you may see the yellow tape cordoning off an area where people can work. You have to think about the general public and the people working inside the perimeter before you use the tape. The first thing you need to do is consider whether to use yellow or red hazard tape. There are other kinds of hazard tapes as well such as what you would use in a crime scene.
You also need to select an appropriate place to access the sectioned off area and the entrance has to be properly labelled. And it is important to secure the tape properly as it can say otherwise and become a tripping hazard. The hazard tape has to be kept in place until the hazard has been dealt with and eliminated. There are many suppliers for hazard tapes and you can actually order these online.

But you need to select a supplier that provides quality labels that are reliable and can withstand a high level of wear and tear. Some hazard or barricade tapes tend to have messages printed on them. Some examples of text used are danger and caution. People will know to tread carefully when there is a caution label. But when there is a danger label, it will prevent people from entering a certain area.