Maybe it helps to make a distinction in protests between coercive tactics and persuasive tactics. Coercive tactics try to impose some cost on the opposition or on those who are in a position to make a relevant change, e.g. changing public opinion/getting the public's attention through some cost to the general public-causing traffic to stop. Persuasive protests, by contrast, try to draw the opposition or bystanders into a discussion and consideration of a different view w/out trying to impose a cost on them.
Coercion can be defined as “any interference by an agent, A, in the choices of another agent, B, with the aim of compelling B to behave in a way that they would not otherwise do” (Aitchison 2018a, 668; see also entry on coercion). Persuasion, by contrast, requires initiating a dialogue with an interlocutor and aiming to elicit a change of position or even their moral conversion.
I'm not a fan of blocking traffic as a protest because the potential for causing more harm seems greater than the probability of causing change by that method. It's not going to make drivers embrace cause
x; it's just going to create resentment. I think any coercive form of protest is going beyond peaceful protest or "civil disobedience." But there are very specific contexts in which peaceful protests make sense, specifically, when those in power recognize, at least on some fundamental level, the rights and agency of the protestors (and the legitimacy of their claims). What happened during the 60s civil rights era would have never worked for Jews under Hitler, I don't think. There are some contexts when civil disobedience seems naive and other measures probably need to be considered.