In a resounding condemnation of government delay, the National Transportation Safety Board on Tuesday said confusing highway signs, driver error and lack of passenger restraints contributed to the deaths of seven people in an I-75 bus crash.

Five members of the Bluffton University baseball team, their driver and his wife died during and after the crash on March 2, 2007 at Northside Drive, where the driver mistook the HOV exit ramp for the HOV through lane.

Lauren Victoria Burke / AP

John and Joy Betts, who lost a son, David, in the Atlanta a bus crash, speak to reporters in Washington on Tuesday before the NTSB meeting.

PAST COVERAGE • INTERACTIVE: The ramp from a driver's perspective • First-person account: A cold chill ran down my spine • Remembering the victims | Photos • Photos: The day's crash scene | The scene at Bluffton THE CAUSE: "The National Transportation Safety Board determines that the probable cause of this accident was the motorcoach driver's mistaking the HOV-only left exit ramp to Northside Drive for the southbound Interstate 75 HOV through lane. Contributing to the accident driver's route mistake was the failure of the Georgia Department of Transportation to install adequate traffic control devices to identify the separation and divergence of the Northside Drive HOV-only left exit ramp from the southbound Interstate 75 HOV through lane. Contributing to the severity of the accident was the motorcoach's lack of an adequate occupant protection system." To see the report synopsis got to: www.ntsb.gov

The driver, Jerome Niemeyer, braked when he reached the Northside Drive bridge at the top, but he was going too fast and it was too late. The bus carrying the baseball team from Ohio crashed into the concrete barrier wall ahead, then vaulted 19 feet back onto the highway below. All 28 surviving passengers were injured.

NTSB investigators said federal and state agencies could have acted long ago on recommendations for passenger restraints and on data that showed other fatal wrecks at the Northside Drive exit.

The crash was a "terrible and tragic accident that I believe, and I think most of us believe, was an accident that didn't have to happen," said the board's chairman, Mark V. Rosenker, speaking of Georgia's confusing HOV signs.

"Since we had seen a history of accidents over about 10 years, had the appropriate investigations been done at the state level, we might not be here today."

At the NTSB meeting in Washington on Tuesday, board members and their staff spoke in frustration of the Georgia Department of Transportation's failure to thoroughly investigate and install clearer HOV signs after crashes started killing people at Northside Drive years ago, and of confusing signs that remain at the exit to this day.

They lambasted the National Highway Traffic Safety Administration for delay in taking up recommendations, first made by the board in 1968, for installing seat belts or passenger safety restraints in buses.

Some board members said they were encouraged by NHTSA's recent studies on passenger restraints and bus crashworthiness but they lamented the delay. Board member Deborah Hersman cited a 1999 NTSB report and said, "it's 10 years later and NHTSA's still tapdancing, and we don't have any standards."

NHTSA spokesman Rae Tyson said the agency had begun crash-testing buses for the first time in December, and any action had to be based on science.

John Betts, whose son David died in the crash, called for legislation (U.S. Senate Bill 2326) requiring bus safety improvements, including seatbelts.

"We saw the bus. Every one of the 55 seats is intact. If those seats are intact, someone give me a logical reason why my son wouldn't be intact," he said. "When I went to the morgue and identified my son back at the hospital, I promised those boys, the Bluffton University baseball team. ... We need to stop the apathy."

Investigators looked at other issues as well. They found that the driver, Jerome Niemeyer, had an expired medical certificate and risk factors for sleep apnea, though there was no proof he had the condition. They found he was awake and in control of the bus at the time of the crash. They said that the bus was going about 65 mph, which was 10 miles over the speed limit but five miles under the average speed for that stretch of road. Niemeyer apparently didn't brake as he passed an "exit" sign at the exit mouth or stop-ahead signs on the ramp.

Investigators said that when the left-hand exits were originally built in the 1980s for use by regular traffic with green guide signs, there was no evidence of traffic fatalities at the Northside Drive ramp. But they said after the HOV system was installed in the mid-1990s, with new white guide signs without a "left" warning, crashes started to happen, including three fatal ones.

Investigators said when the HOV signs were first installed, there was little experience in the nation with HOV systems, and the signs didn't violate U.S. guidelines. But enough crash data has accumulated over the years since then to call for Georgia to change the guide signs.

"You know there's a problem," said Bruce Magladry, NTSB's director of highway safety. "Fix your location. Now."

One of the signs criticized hangs above the exit mouth without the word "exit" on it, pointing HOV drivers up the ramp to "Northside Drive."

An Atlanta Journal-Constitution review of old DOT documents found that that sign originally was supposed to hang next to a second sign that would point out the HOV through lane. Georgia engineers realized they weren't supposed to use the type of pole called for in the plans, a pole big enough for two signs. Under the gun to finish the project before the 1996 Olympic Games and without a two-sign pole, they kept the overhead sign pointing up the ramp to Northside Drive but left the HOV through-lane sign off the exit.

Georgia DOT officials changed some smaller signs and pavement markings after the bus crash, but still have not changed the larger guide signs that experts have criticized. DOT commissioner Gena Abraham said in a statement Tuesday, "We do understand. We are going to consider every option put before us by the NTSB and the Federal Highway Administration" and she added the "process has already begun."

The green signs with yellow "left" warnings came out of a review by the FHWA of HOV signs nationwide after the bus crash. Georgia DOT officials requested the review after the crash, and have said they intend to change those larger signs, if possible.

As to reacting to the crash history earlier, a DOT spokesman, David Spear, said in an e-mail Tuesday that DOT does review safety data for trends, but the timeliness and detail in those reviews vary from jurisdiction to jurisdiction.

Last year, when The Atlanta Journal-Constitution undertook to compare and analyze crash rates at Northside Drive and other left-hand exits, DOT's office of Traffic Safety and Design seemed to be crunching the numbers for the first time. Its safety program manager told the AJC there were 82 accidents at that ramp rather than the correct eight or nine.

Chastened by the mistake, the office spent a month reading crash reports to answer AJC questions comparing fatalities at all HOV left exits. Officials said they also had no comparison of crash rates at left-hand exits versus right exits and found that no data had been entered at one HOV exit for years.

The five-member NTSB has the power to make findings and recommendations but not to enforce them.

Cox Washington bureau staff writer Scott Girard; Dayton, Ohio, Daily News correspondent Jessica Wehrman and AJC data analyst Megan Clarke contributed to this article.