Rolling burning tiers symbolizes the
"Protest".
It symbolizes the objection to something and disapproval against to official policy.
Mostly, people burning the rolling tiers because it attracts the attention of others.
Burning tires produces thick black smoke that can be used as a signal to other protesters, and provides a means of communication that a government can't easily disrupt. An organized protest that can communicate is far more dangerous than a general unruly mob. The Smoke also makes it harder for law enforcement to use helicopters to gather intelligence and monitor the situation. Burning tires makes almost every aspect of suppressing a protest harder.