WASHINGTON – As a Senate panel investigated passenger bus safety, the U.S. Department of Transportation on Wednesday shut down the Wilkes-Barre-based bus company involved in a deadly accident earlier this month.

The bus operator, Super Luxury Tours, violated federal insurance requirements, the transportation department said. One of the company's Philadelphia-bound buses crashed on the New Jersey Turnpike on March 14, killing the driver and one passenger.

The move to close down the bus company came on the same day a Senate subcommittee chastised the department for moving too slowly to improve bus safety.

"I'm concerned that the Department of Transportation isn't moving quickly enough to implement its 2009 plan to make motor coaches safer," said subcommittee Chairman Sen. Frank Lautenberg (D., N.J.). "…It is also unacceptable that bus companies continue to put unsafe drivers and buses on the road.

"Just because bus companies can discount prices doesn't mean they can discount safety."

Lautenberg called the hearings after the New Jersey bus crash and an accident two days earlier in New York City that killed 15 and injured 18.

At Wednesday's hearing, safety experts urged the transportation department and Congress to move quickly to require seat belts in buses, standards mandating strong roofs and windows, and the installation of instruments to warn of impending collisions or unsafe driving.

Previous calls have long been ignored, the safety officials said, noting that the National Transportation Safety Board first recommended bus seat belts 40 years ago.

A bus industry official, Peter J. Pantuso, said the industry was not opposed to seat belts or other safety requirements, but he said the costs would add about $75,000 to the current $500,000 price tag of a new bus.

A bus safety advocate, Joan Claybrook, said the industry cost estimates were "hogwash," and she said experience in Australia and Europe, where seat belts are required, suggested the safety measures would increase costs of a typical bus ticket by 5 to 10 cents.

With family members of bus crash victims in the audience, Sen. Kay Hutchinson (R., Texas) said she expected Congress this year to pass bus safety legislation that has languished for four years. Hutchinson sponsored the bill, along with Sen. Sherrod Brown (D., Ohio).

"We're going to pass it this year," Hutchinson said. "It's incomprehensible that it's taken this long."

About half of all bus fatalities in recent years have occurred as the result of rollovers, and about 70 percent of those killed in rollover accidents were ejected from the bus,

according to the Transportation Department.

"It's frustrating to be on the sidelines and get called to yet another accident in (New York) and know the issues that we've made recommendations on are stagnating," NTSB Chairwoman Deborah Hersman told The Associated Press before the Senate hearing Wednesday. "If the regulatory agency had moved on their rulemakings, or the Congress had required these things to be done, we might have been able to prevent some of these fatalities."

The families of victims said they share Hersman's frustration.

"It just seems to us that four years is long enough to wait on such simple, straight forward legislation that needs to be enacted," said John Betts of Bryan, Ohio, whose son, David, was among five Bluffton University baseball players killed in 2007 when their bus careered over an Atlanta highway overpass.

The safety board has scheduled a public forum in May on the Transportation Department's progress in implementing bus and truck recommendations.

In November 2009, Transportation Secretary Ray LaHood released a plan for issuing regulations that address many of the NTSB recommendations. The only recommendation that has been fully implemented is a ban on texting by bus and truck drivers. The department also has proposed rules requiring seatbelts for all bus passengers and electric onboard recorders, and a ban on handheld cellphone use by bus and truck drivers while driving. Those rules have not been made final.

This article contains information from the Associated Press.