Darcie Lanthier said in a telephone interview that she was taken into custody at the construction site about 30 kilometres west of Charlottetown after refusing to leave the area.
Opponents of the $16-million highway project say it will destroy arable fields and an untouched stand of old-growth hemlock, as well as a popular hiking trail and a fishing area.
Lanthier, 50, of Charlottetown said she was released and expects to be charged with resisting arrest and mischief.
RCMP Sgt. Andrew Blackadar said a woman was arrested and will face criminal charges of mischief and resisting arrest.
He declined to release the woman's name but he said she is scheduled to appear in provincial court on Dec. 3.
Blackadar alleged the woman was lying in camouflage gear in front of a tractor before police carried her from the site.
He also said five protesters were issued summary offence tickets for trespassing earlier Tuesday after refusing to leave the fenced-off area.
Lanthier said the protesters want to slow down the project while legal efforts continue in the courts to impose a temporary stop to the work.
"We're just playing sort of a beat-the-clock game here. We're in the courts to try and get an injunction to stop this, and in the meantime the construction is proceeding as fast as possible to do as much damage before they have to be in court," she said.
She alleges that the stands of wood being cut are rare and the province is losing a precious resource.
"Four thousand people signed a petition against this project," she said.
"It's running through a 220-year-old stand of hemlock forest. On Prince Edward Island there's less than five of these ... and the rest (of the road) is going through farmland," she said.
"The whole thing is based on this fallacy that this section of the road is dangerous when we know in fact it's not."
The provincial Transportation Department's website says the 5.8-kilometre road has passed an environmental assessment, and that it is spending an additional $4 million to purchase land needed for the highway construction.
The department says the highway from New Haven to Bonshaw "is being rebuilt to bring it up to today's standards."
"The Trans-Canada is our busiest route, our main trade corridor, and most important highway. It must be held to higher standards than secondary roads."
A news release on the website says many curves on the road are too sharp and hills are too steep, making it difficult to maintain a reasonable speed.
Lanthier said protesters would remain in tents in a hemlock forest near the construction site and protests against the project will continue.
Alyssa MacAusland, 25, who was camping in the woods near the construction site on Tuesday night, said she was willing to risk arrest to stop the project.
"We have our base camp set up in the woods and we plan on staying there until tomorrow morning and hopefully we'll save those trees," said MacAusland, who estimated there are about 30 protesters in the woods.
"It's rare to find ecosystems that are still able to sustain such big trees," said MacAusland, a recent science graduate from the University of Prince Edward Island.
"We have a lot of people here that are extremely passionate and willing to put themselves in the line to prevent the devastation from happening."
— By Michael Tutton in Halifax.