TRENTON - Construction along the New Jersey Turnpike has been a boon for a small group of state troopers who oversee the work zones.

A review of state payroll records by the Star-Ledger of Newark found six of the nine troopers assigned to the squad were among the top 20 overtime earners in the division last year. Most boosted their salaries by 50 percent or more.

The six troopers tallied a combined $275,549 in overtime, an average of $45,924 each. That was four times the average paid to all troopers who earned overtime last year.

The squad leader earned $63,221 in overtime and $167,890 overall, topping all other troopers, including Superintendent Rick Fuentes, who earned $144,966.

Through September, seven of the troopers were among the top 22 overtime earners, having tallied $264,313. With about $50,000 in overtime, the squad leader is again on pace to earn more than any other trooper.

The overtime is ultimately paid by the Turnpike Authority and commuters, who face a 53 percent toll increase on Sunday to help pay for a decade-long, $7 billion capital program to widen the turnpike and the Garden State Parkway.

Lt. Stephen Jones, a state police spokesman, told the newspaper the division closely monitors overtime and reviews schedules to reduce costs. He said only a handful of troopers were trained to work in turnpike construction zones, and with the immense amount of work being done, the extra pay was a "necessary expense to take care of business."

"There's a limited pool of troopers to draw from, and we can't afford to take troopers from other assignments and assign them to that unit at this point," Jones said.

Tom Feeney, a spokesman for the Turnpike Authority, which reimburses the state police for patrolling the highway, said the division does an excellent job controlling costs. Feeney also noted that the division reduced its budget for manning the turnpike and the parkway by $1.3 million in 2012, compared with 2010.

"The amount they've spent on overtime has been in line with our expectations and seems entirely appropriate," Feeney said. "Any discussion of who makes how much or how it compares to what others make seems very much beside the point."

The squad on the turnpike is responsible for supervising work zones, including making sure cone lines and barriers are placed at proper distances, and giving drivers enough space to slow before merging, Jones said. The squad also watches over any other troopers who may be assigned to construction details, he said.

"When traffic patterns are changed, there's a science as to how to do that safely," he said. "That unit contains all the experts in that field for the turnpike. Really, it's about safety, and we can't compromise on that."