A stretch of the Indiana Toll Road where at least 12 people had died since August 2005 claimed eight more lives Thursday when a semitrailer barreled through stopped traffic, crushing several vehicles in a chain-reaction crash.

State police said the driver of the semi never slowed until he struck the vehicles, which had stopped because of a separate crash near a construction site. Two of the vehicles were crushed beyond recognition -- a pickup truck carrying six people, five of whom died, and a Jeep Cherokee in which two were killed. The driver of another pickup truck that was knocked off the road also died.

"At this point, we don't know the reason. He did not slow down," state police Sgt. Trent Smith said. "It's one of the worst accidents that we've had up here."

State police reported those killed included Cherokee occupants Douglas and Mary Helen George of Springfield, N.H., along with pickup truck driver Mark Repp of Sturgis, Mich. Three passengers killed in the other truck were Merle Miller, 44, of Ligonier, Ind.; Samuel Yoder, 46, and his son, Anthony Yoder, 17. The names of the other two killed were not immediately released.

The driver of the truck in which the five people died -- Wayne Lehman of LaGrange -- was listed in critical condition at Memorial Hospital in South Bend.

While investigators blamed the crash on driver inattention, no charges were immediately filed against the semi driver, Leonardo Cooksey, 31, of Mount Prospect, Ill. Investigators said they would send their report to the county prosecutor for review.

Messages seeking comment were left at Cooksey's home telephone number and for a manager at New England Motor Freight of Elizabeth, N.J., to whom the semi was registered.

The crash brought to at least 20 the number of people killed in collisions involving semitrailers and multiple victims since August 2005 on a short stretch of the east-west tollway, which also is Interstates 80 and 90.

Those crashes, plus two involving semitrailers on Interstate 69 -- one a year ago that killed four Taylor University students and a staff member and one April 19 that killed the daughter of state Sen. Timothy Skinner -- prompted a call for action from state lawmakers Thursday.

The state Senate passed a resolution sponsored by Sen.Tom Wyss, R-Fort Wayne, calling for a study committee on vehicle crashes involving commercial motor vehicles.

Wyss said he has been concerned for some time about the number of large trucks passing through Indiana. The death of Skinner's daughter, who died when her car was struck from behind by a semi, and Thursday's crash reinforced his concerns.

"Eight deaths, one crash. Whatever you do, don't call them accidents," he said. "They are crashes, and they are done by irresponsible, aggressive commercial vehicle drivers."

Kenny Cragen, president of the Indiana Motor Truck Association, said he supports the study.

"I think it needs to be done. We've got to do everything we can to prevent accidents like today from happening again," he said.

Matt Pierce, a spokesman for toll road manager ITR Concession Co., said the key to preventing such accidents is more police patrols.

"That's exactly what's going to slow them down," he said. "It's the individuals driving the big rigs. If they are driving at a high rate of speed, it's hard for them to stop. They have a burden to keep at a safe distance."

Pierce said an Indiana Department of Transportation team would be looking at the road to determine whether there is a reason so many fatal crashes have occurred. INDOT spokesman Andy Dietrick said the team would also review whether steps could have been taken to prevent the accident.

Smith said the crash happened about 6:45 a.m. in the tollway's westbound lanes about 1 1/2 miles before the start of a construction site where highway workers are rebuilding a bridge. Traffic had come to a standstill in the right lane and was moving slowly into the left lane.

He said the warning signs were posted along the highway up to three miles from where the construction site began.

"There are thousands of people that travel these roads every day. All it takes is one person not paying attention for a split second to cause these accidents," Smith said.

Bristol Fire Chief William Dempster said four of the victims were Amish residents of nearby LaGrange County, one of the nation's largest Amish communities.

While Amish typically do not drive motor vehicles because they don't want to depend on technology, Amish workers often hire drivers to ferry them to work, said Joseph Yoder, director of the Menno-Hof, a nonprofit information center in nearby Shipshewana that teaches visitors about the Amish and Mennonite.

Many public telephones in Amish areas have lists of drivers who can be hired, Yoder said. Steven Nolt, a Goshen College history professor who has written several books about the Amish, said Amish frequently travel together in work crews and hire a driver.

About 14,000 Amish live in western LaGrange and eastern Elkhart counties, Nolt said.

Yoder said the deaths would hit the Amish hard because they are so community oriented.

"But they will accept it as being God's will," he said. "You don't question God."

The accident scene about one mile east of Bristol is near a crash site that killed five people last year on the tollway.

Westbound lanes were closed about 40 miles west of the Ohio state line until 3:30 p.m.