Money can strain relationships.

Collin County commissioners see dollar signs – billions of them – when they view future extensions of the Dallas North Tollway. And that's what prompted them to rescind a three-year-old agreement to share the road's right of way with Denton County.

Commissioners now want a future tollway extension from Celina to Grayson County to be entirely within Collin County, not straddling the Collin-Denton county border as planned. On Tuesday, commissioners voted unanimously to rescind a 2005 agreement supporting the current alignment.

"The DNT [Dallas North Tollway] is a tremendous economic generator," Collin County Judge Keith Self said.

The vote is symbolic, as the North Texas Tollway Authority ultimately will decide where to build the seven-mile extension. No timeline has been set for the decision or for construction, and completion could be many years away.

On Wednesday, Denton County officials criticized their Collin County counterparts for wanting to move the route.

"We entered into an agreement to help residents of both Collin and Denton counties," Denton County Judge Mary Horn said. "This was agreed upon a long time ago. I don't plan on making any changes. I plan on honoring the agreement."

Denton County Commissioner Cynthia White, whose district abuts Collin County, also criticized the vote.

"We shouldn't be determining a line based on economics," she said. "The primary purpose of this project is regional mobility."

Mr. Self said Wednesday that he had no regrets about the vote.

"This Commissioners Court represents Collin County, and we need to represent Collin County well," he said. "I think Denton County ought to understand our action on behalf of our citizens."

In January 2005, commissioners in Collin and Denton counties approved almost identical resolutions that supported a tollway alignment straddling the two counties. Denton County passed the measure unanimously.

Collin County Commissioner Jerry Hoagland cast the only no vote in 2005. He argued that the alignment should be entirely in Collin County.

"I've always contended we needed to keep this roadway, as much as possible, in Collin County for the economic benefits," Mr. Hoagland said at Tuesday's meeting.

Collin County staff members presented a report that showed the financial windfall associated with the Dallas North Tollway.

For instance, land along the tollway in Collin County is now valued at about $10 billion, according to county appraisal records. The figure includes property up to a mile east and a mile west of the tollway.

Rick Herrington, NTTA's deputy executive director, told commissioners that the agency had just begun to study alignments for the route from FM428 to the northern Collin County border.

"We will look equally at all alternatives," he said.

Dan X. McGraw of the Denton Record-Chronicle contributed to this report.