In this 2006 file photo, then-Massachusetts Gov. Mitt Romney, right, looks over bolts in the ceiling of a Big Dig tunnel while speaking with Alexander Bardow, center, Massachusetts Director of Bridges and Structures, and Massachusetts Secretary of Transportation John Cogliano in Boston. (DAVID L RYAN/ASSOCIATED PRESS)

Mitt Romney was used to summoning state officials and having them appear. So when the head of a troubled agency stood him up in the middle of an emergency, the Massachusetts governor was furious.

A tunnel ceiling collapse in July 2006 had killed a mother of three, the latest crisis for the massive Boston construction project known as the “Big Dig.” But Matthew Amorello, the official overseeing construction, had ignored Romney’s summons and instead held a televised news conference at the accident site.

Romney took off for the tunnel, his face red and his jaw set, aides said. He stormed out of his car so fast his staffers scrambled to keep up, and upbraided Amorello in a scene captured on Boston television. “It was the one time I saw him explode,’’ said Thomas Trimarco, a Romney cabinet member.

It was also the moment Romney took control of the Big Dig, one of the state’s most infamous and vexing problems, and one that had hung over him for 3 1 / 2 years. The project was billions of dollars over budget, years behind schedule and riddled by allegations of corruption — a mess that Romney had inherited and vowed to fix when he became governor.

Romney’s plunge into the Big Dig offers a case study of his management style, one molded by the private sector experience he promises to bring to the White House. Faced with a crisis, he set out to diagnose the problem and master the engineering details, then ordered a top-to-bottom safety review.

As a former business consultant, the frenzied atmosphere “played to his skills,’’ said Kerry Healey, Romney’s lieutenant governor: “He’s a smart guy, and the whole notion of consulting is, you go into a business you don’t know, and learn it so well that you can quickly tell the people whose business it is how to do it better.’’

Yet after the crisis faded, his attention receded as well, a critique that dogged him at other points during his governership. When he took office in 2003, for example, the novice politician faced what he called a “financial emergency,’’ a nearly $3 billion state budget gap.

Working closely with the Democratic-controlled legislature, Romney rapidly won sweeping emergency powers to cut spending. But after the immediate budget crisis passed, his relationships with legislators frayed when he targeted many of them for defeat in midterm elections.

Romney also zeroed in on a Massachusetts judicial nominating system he saw as riddled with patronage and favoritism. He announced widely hailed reforms, yet reversed them as he geared up to run for president in 2008 and appointed some lawyers with political or personal ties to the bench.

The governor’s business background was perhaps most apparent in his effort to revamp what he saw as a highly inefficient higher education system. He brought in consultants from his former firm, Bain & Co., who helped craft far-reaching proposals.

But Romney’s plan to privatize some schools and merge others quickly died in the Democratic-controlled legislature, and he never reintroduced it.

In the case of the Big Dig, critics said, as Romney’s term wound down he shifted his focus away from tunnel repairs to concentrate on his first presidential run. And a bigger problem emerged when he was out of state: that his administration had hired the same firm that was under criminal investigation for the collapse to inspect the repairs. That move triggered a federal audit.

A 2006 report from the state inspector general concluded that Romney’s administration and the independent Massachusetts Turnpike Authority “failed to uphold the most basic function of government in their stewardship . . . to protect the safety of the public.’’ Romney supporters dismissed the report as political and unfair.

Ryan Williams, a Romney campaign spokesman, said the former governor had faced enormous obstacles, but succeeded in dealing with the construction project.

“As governor, Mitt Romney pushed to bring accountability to the Massachusetts Turnpike Authority and end the culture of cronyism and mismanagement that plagued that agency for years,” he said. Romney’s efforts to oversee the Big Dig, he said, were “repeatedly blocked and undermined by an entrenched political establishment.”

Boston’s Panama Canal

Planners had envisioned the Big Dig as a state-of-the-art network of tunnels under downtown Boston and its harbor, new bridges and an interstate extension. But the challenges were massive — some compared the project to building the Panama Canal.

Under a series of Republican governors and Democratic legislatures, the pricetag for the $2.6 billion project had ballooned to nearly $15 billion and construction, which had begun a decade before Romney was elected, was five years behind schedule.

Despite his vow as a candidate to bring the Big Dig under control, once elected, Romney faced his own challenges, including a partisan political culture and a Byzantine oversight structure. The turnpike authority, not the governor, ran the project, and the authority did not report to Romney.

“From a purely managerial standpoint, there was an inefficiency screaming out to be solved,’’ said Healey, Romney’s lieutenant governor.

Romney proposed a merger of agencies that would give him authority over the project, but it went nowhere in the Democratic legislature.

“When you just propose stuff here it doesn’t go anywhere unless you work it,’’ said former state senator Bob Havern (D). “He was sort of aloof and said, ‘Okay, I’ll just propose it, I’m the CEO.’ But this is the least similar thing to a business in the history of the world. It’s a smelly, sweaty war every day.’’

Trimarco, Romney’s secretary of administration and finance, said the governor had made a realistic calculation: His merger plan had no chance, so he pushed other priorities, such as health-care reform.

“The governor is a serious person, far more serious than the average legislator. He’s not a backslapper, and he wasn’t going to charm them to death,’’ Trimarco said. “It wasn’t going to happen, and he realized it, and he stopped pursuing it until the ceiling collapse.’’

Even before the collapse, however, he had gone after Amorello, the official he confronted at the scene of the accident. Amorello was a veteran Republican politician who headed the turnpike authority. Romney for several years had been calling for his resignation, but that had also run into political reality — Amorello was a former state senator with close ties to lawmakers.

Former aides say Romney found Amorello to be unqualified and a poor manager of an agency riddled by patronage. Other Massachusetts politicians said Romney focused his blame too narrowly on Amorello, making it a personal quest.

“Amorello was an easy political target,” said State Sen. Marc R. Pacheco (D), adding that Boston residents “hated the turnpike authority.’’

Amorello , who was forced out after the tunnel ceiling collapse, did not respond to e-mails requesting comment, and several members of his family did not return telephone calls.

Romney didn’t help himself with legislators when he fought them over symbolism. Many Democrats had long expected to name the main Big Dig tunnel after Tip O’Neill (D), the legendary former U.S. House speaker who was instrumental in funding the project.

Romney and legislative leaders instead proposed calling it the “Liberty Tunnel” in honor of Iraq War veterans. But when numerous other Democrats objected, Romney resisted for months and the uproar only intensified when his spokesperson appeared to question the patriotism of those who disagreed. Romney eventually lost the battle.

“If you really wanted to get Amorello out, why do you go and tick people off about Tip?’’ said David Luberoff, former executive director of Harvard University’s Rappaport Institute for Greater Boston, which focuses on improving governance in the area.

Seizing control

Milena del Valle, a native of Costa Rica, was en route to Boston’s Logan International Airport with her husband late on July 10, 2006, when the tunnel ceiling partially collapsed. Del Valle, 38, was crushed in the passenger seat of the 1991 Buick. Her husband escaped with minor injuries.

The accident dominated news coverage for days amid massive traffic jams and fear among drivers. Romney convened his advisers, vowed to get to the bottom of the collapse and renewed his call for Amorello’s departure, former aides said.

Romney demanded a briefing from engineers.

“He’s constantly asking questions, saying, ‘I understand that, let’s go to this,’ ’’ said Trimarco, who attended the session. “And, I’ll never forget this, when they finish, Romney says, ‘Okay, I think I got it, I want to have a press conference at 4 p.m.’ ’’

At a series of news media briefings, he drew diagrams on an easel with technical detail and explained what might have caused the collapse.

“It was his finest hour,’’ Trimarco said. “He immediately took charge. He really was starting from ground zero, and he was up to 60 miles per hour in like three seconds.’’

Romney took advantage of the newly receptive mood among legislators shocked by the accident. Dispatching aides to Boston’s Beacon Hill, within 72 hours he pushed through legislation giving him control over safety inspections and reopening the tunnel.

Williams, the Romney campaign spokesman and an aide during Romney’s governorship, said legislators should have acted much earlier. “It took the tragedy in the 1-90 tunnel and the ensuing public outcry to finally convince the Legislature to give Governor Romney the power to make much needed reforms to ensure confidence in the Commonwealth’s transportation infrastructure,” he said.

A few weeks later, Amorello resigned under pressure after Romney invoked a provision in state law permitting the removal of a public official for cause.

The governor also hired a firm to review Big Dig tunnel safety, set a 90-day deadline and personally reported the results to the public.

The National Transportation Safety Board later concluded the probable cause of the accident was flawed epoxy, or adhesive, that fractured and caused ceiling support anchors to pull free. The report primarily blamed Bechtel/Parsons Brinckerhoff — the engineering firms that formed a joint venture to manage construction — and another contractor that Bechtel managed for failing to identify the potential problem. A Bechtel/Parsons Brinckerhoff spokesman declined to comment.

Pointing fingers

As Romney’s term wound down, the bipartisan praise for his performance turned to criticism. Democrats said he had lost his focus on the problem; former Romney aides counter that he was always in touch and in command.

Three months after the collapse, Massachusetts Inspector General Gregory W. Sullivan issued a critical report, noting that although Romney a year earlier had announced a review of tunnel safety, the review was never done, other than a limited inspection of a single tunnel.

Romney’s adminstration had assured holders of the state’s bonds that the review was being conducted, state documents show. That assurance triggered an inquiry by the Securities and Exchange Commission, which sought safety records from the state, but ultimately brought no charges.

The highway department “abdicated its role as a second set of eyes on this critical piece of infrastructure,’’ wrote Sullivan, a former Democratic state legislator.

Warren Tolman (D), also a former Massachusetts state legislator, called the report “an indictment of Romney’s leadership.’’ But Romney aides questioned Sullivan’s objectivity.

Trimarco, noting that Romney had tried to eliminate Sullivan’s office several years earlier, said: “Do you think that man didn’t have a score to settle? It was payback.’’

Sullivan, whose term recently expired, said through a spokesman that he stands by his report.

Romney also came under fire that October when the Boston Herald revealed that his adminstration was paying Bechtel/Parsons Brinckerhoff to help inspect the repairs — essentially to evaluate its own work. At the time, Bechtel/Parsons Brinckerhoff was one of several Big Dig firms under investigation for the tunnel collapse by the Justice Department and state authorities.

Romney blamed John Cogliano, the man he had installed to replace Amorello, for allowing Bechtel/Parsons Brinckerhoff back into the tunnel for inspections. Cogliano said at the time that he was unaware of the companies’ involvement and ended the arrangement. He did not return telephone calls and e-mails seeking comment.

Romney himself had expressed “very serious concerns” about the companies’ work after the collapse, saying: “At a time like this, Bechtel isn’t real credible on safety.”

The companies’ role triggered a federal audit, which concluded that the inspections had threatened to “undermine the public’s confidence” and noted that the state had to repeat 193 inspections.

In 2008, Bechtel/Parsons Brinckerhoff agreed to pay the state and federal governments $399 million to settle the criminal and civil probes related to the accident.

At the time, the companies said their performance “did not meet our commitment to the public or our own expectations,’’ adding the Big Dig “remains one of this country’s most remarkable infrastructure achievements.’’

Romney left office in January 2007 and would cite his handling of the tunnel crisis as his presidential campaign geared up.

Today, state officials in Boston agree that the Big Dig has reduced traffic congestion and provided other benefits, including numerous parks and public plazas. But problems remain. Sections of concrete that were expected to last decades already are crumbling. And last year, a 110-pound light fixture crashed onto the roadway, unleashing a new round of finger-pointing.

Research editor Alice Crites contributed to this story.