But the historians add that Daniels could build a more significant legacy by pouring as much energy into education, health care and mass transit as he has spent on economic development.
"It seems likely that he is a governor of consequence, a governor who has made things happen," said James Madison, an Indiana University historian and author of books including "The Indiana Way."
However, he added, "There is a lot to be done."
Ball State University historian John Mathew Glen said Daniels should turn his attention from highways to mass transit.
Highways are "so 20th Century," said Glen, who is writing a book about the state's past 50 years for the Indiana Historical Society.
Daniels is widely expected to announce a re-election bid at a June 16 event at Butler University's Hinkle Fieldhouse, the location where he made public his first run for the office. However, his administration hasn't disclosed the purpose of the event.
Madison and Glen said that regardless of whether one agrees with Daniels' agenda, he is one of the most activist governors in memory.
Daniels is no revolutionary, nor are his changes radical, Madison said. However, he added, the changes are "substantial."
Madison said Matthew Welsh, a liberal Democrat who held office from 1961 to '64, put Indiana ahead of most states and the federal Civil Rights Act of 1964 by starting a state agency to oversee civil rights.
Daniels instead has focused most of his attention on economic development-more so than Republican Gov. Robert Orr, who in the 1980s attracted Japanese manufacturing plants, or Democrat Frank O'Bannon, who reorganized the Department of Commerce early this decade, Madison said.
Daniels entered office at an unusual time in state history, Madison pointed out. Decades of battering by manufacturing plant closings and layoffs, coupled with a "broken" health care system and struggling schools forced many Hoosiers to look for change.
In fact, Daniels has been so successful in bringing about changes that Madison is considering revising at least one of his books that's predicated partly on the state's reputation for stubborn resistance to change.
"He has introduced change in a way that is very difficult to do in Indiana-exceptionally difficult," Madison said. "Hoosiers are very wary of change."
Glen said the transition to service industries from manufacturing, the rise of race and gender in public policy, and the suburbanization of Indianapolis were making Indiana more like the rest of the country even before daylight-saving time was passed.
While that change caused the state to lose another distinguishing characteristic, it will make businesses more competitive, Glen predicted.
The other centerpiece of Daniels' accomplishments is the toll road lease, he said.
It's far too early to know if the lease will benefit the state in the long run, Glen said. But Daniels is being viewed as a trendsetter. Other governors, including Democrats Ed Rendell of Pennsylvania and Jon Corzine of New Jersey, want their states to take up similar deals.
"If the toll road privatization brings benefits to the state, he will be judged a success," Glen said.
Ironically, Glen added, if Daniels runs for a second term and loses, he probably would be defeated by backlash from the toll road lease, not from daylight-saving time, which stirred so much controversy that it passed the House by just one vote.
People are adjusting to daylight-saving time nicely but harboring resentment about leasing a publicly funded project to a private party, Glen said.
If Daniels were to win another term, he would need to accomplish far more with education, health care and mass transit in order to be considered one of the state's great governors, Madison and Glen say.
The state's education system is woefully inadequate to teach Hoosiers to compete against rising global competition, Madison said. Even the developing nation of China prepares students better in math than do Indiana schools, he chided.
Glen criticized Daniels for a seeming fixation on building highways, including the Illiana Expressway linking northern Indiana with Illinois, and the Indiana Commerce Connector that would have tied together Pendleton, Greenfield, Shelbyville, Franklin and Martinsville.
Both ideas fizzled in this year's General Assembly after hornet nests of citizens turned out at meetings in opposition.
Mass transit is the transportation of the future, Glen said.
Glen also is disappointed that Daniels has spent a lot of energy attracting manufacturing projects including the Honda Motor Co. Inc. car assembly plant at Greensburg. Manufacturing jobs will continue to whither, and should be replaced by jobs in other industries, he contended.
"Indiana faces deep-seated problems," Glen said. "We're right back to manufacturing."