Neighbours of a school have used wheelie bins to block access to their street to stop parents using it to drop off and pick up children.
Residents said they had to "make a stand" about the traffic after a gate at Cleethorpes Academy was reopened following a 10-year closure.
Police said officers were called to "a small protest and highway disruption" at Halton Place on Monday afternoon.
The school said the gate had been reopened to help meet Covid guidelines.
The emergency gate had become operational to "manage student flow" and to ensure safety during the pandemic, said Principal Janice Hornby.
Pam Ireland, who lives on the street, said: "We knew we were breaking the law by blocking a main road, but we have to make a stand."
Neighbour Michelle Crews said: "It's just manic. We want it stopped. This is a small cul-de-sac, it's not built for loads of cars."
She added that she was also concerned by some pupils who were "riding their bikes on the paths and in the middle of the road".
Another Halton Place resident, who did not give their name, said: "My main concern is people not being able to get in and out of the cul-de-sac when they need to."
However, one parent, who wished to remain anonymous, said she had felt "threatened" by the demonstration on the street.
"I just want to pick my lad up and go home. I don't want all this hassle and heartache they're causing us. It's not acceptable.
"I just don't know what the problem is. There are no double yellow lines and anybody can park here because it's not a private road."
In a letter to parents, Ms Hornby asked parents not to park their cars on Halton Place and "under no circumstances block the driveways of residents".
She said the school would continue to use the emergency access gate as it was "more convenient for some students" and helped reduce overall congestion in the area.
Ms Hornby told the BBC: "I've had parents in tears as well as children. So I am extremely disappointed."
A meeting is due to be held with councillors, residents and police to "find a solution", she added.
Bob Callison, Conservative councillor for the Croft Baker ward on North East Lincolnshire Council, described the barricade as "people power".
He said residents had faced "enough disturbance and wanted some peace".