U.S. Secretary of Education Arne Duncan arrived at a South Side elementary school Thursday morning for an event — but his driver took a wrong turn down a dead-end alley, and Duncan was forced to walk half a block to the school amid protesters who’d been waiting for him to complain about standardized testing.

About 50 parents and children stood outside Ariel Community Academy so they could deliver their message to him about their opposition to the PARCC test. They chased his black SUV when it turned short of the school into an alley.

But the alley was a dead end. The SUV stopped. Duncan got out in his shirt-sleeves, his suit jacket over one arm.

He strode back up the heavily puddled alley to the nearest school entrance, smiling at the chanting (“Chicago hates the PARCC”) and signs (“Arne, Rahm, Park the PARCC, stop test bullying.”) Aside from a few pleasantries, he did not speak to the people surrounding him.

“There’s no way he didn’t see why we’re here and why we we’re protesting,” said Lynn Ankey, mother of two at Belding Elementary School on the Northwest Side. “Despite the bullying by ISBE (Illinois State Board of Education) and by him to ISBE, we’re not giving up and we’re still going to stand up for our kids.”

Duncan was expected inside along with Mayor Rahm Emanuel, CPS CEO Barbara Byrd-Bennett and Ariel Investments President Mellody Hobson to announce a new financial education program.

Once safely inside the school, Duncan was asked about the protest outside.

Why is his U.S. Department of Education forcing a controversial standardized test — one many parents don’t want and that Mayor Rahm Emanuel has argued is “not ready” for prime time — down the throats Chicago Public Schools?

“I’m not,” Duncan said. “The state works it out without Chicago. . . .  That’s the state’s decision.”

But isn’t the mandate being dictated by the federal government? Isn’t that what’s behind the threat to withhold $1 billion in funding that forced Chicago’s hand?

“No. You’re wrong. . . . You’re making stuff up. You don’t have your facts straight,” Duncan said.

The secretary was asked about the parental animosity stemming from the PARCC test and the resulting protest that forced him to go through the gantlet of protesters to get into Ariel Community Academy, 1119 E. 46th Street.

“I welcome the conversation. It’s good. . . . It’s a healthy conversation to have,” he said.

But he said, “It’s important to assess kids annually. . . . Millions of kids around the country are taking the test. We’re fine.”

With that, a press aide to Duncan stepped in and ended the interview.

Emanuel and Byrd-Bennett entered through a back school door, but CPS parent Jennie Biggs said Byrd-Bennett gave her a “fist pump” through the car window when the schools chief saw Biggs’ sign reading “Arne!” and “PARCC bullying” with a red circle and line through it.

CPS began administering the new PARCC exam Monday to students in grades three through eight, as well as some high schoolers; CPS backed down on a plan to test just 10 percent after ISBE threatened to withhold $1.4 billion in state and federal money. The state board said giving PARCC is a federal requirement, which Duncan’s department hasn’t waived for Illinois students.

This marks the first year in which PARCC is being given on a full scale in about a dozen states. While pleading for the pilot program, Byrd-Bennett said that CPS students weren’t technologically ready for the computer-based test, saying PARCC would end up testing their computer literacy rather than their reading comprehension. CPS students are also in the rare spot of having to take another standardized test this year — the NWEA MAP — to fulfill state requirements for teacher ratings.

Some parents have responded by opting their children out of the test — which in Illinois requires the child to refuse the exam when presented with it.

Last week, Mayor Rahm Emanuel maintained that the test was “not ready” for prime time, but said elementary school students must take the exam because Chicago Public Schools simply cannot afford to lose $1 billion.

“Once the federal government and the state were threatening to cut hundreds of millions and billions of dollars off, which would have dramatically increased the teacher-student ratio, it was clear that that was . . . a bridge too far,” the mayor said.

Emanuel noted that Chicago was one of the nation’s first big cities to adopt and integrate the state standards widely known as Common Core.

“That said, it doesn’t mean that the federal government was right in where the test was. We wanted to see them work through the bugs,” Emanuel said.

“But once the kind of threat [was made, Chicago had no alternative]. There’s no other way to say it. They were going to cut off the resources. It was either take the test or [else]. Given all of the financial challenges, you could not have the school system [defy the mandate]. It would affect the classroom itself. So we were quite clear that we would bend to that order, not willingly, but accept the reality that losing $1 billion was a bridge too far for the schools.”

Emanuel cut off the questioning before he could be asked about parent-led student boycotts or about whether he had lobbied the state and federal government behind the scenes to delay the test or drop the threat of penalties.

But before he left, the mayor made it clear that his hand-picked school team not only accepts the common core standards, but also believes those standards are the “right thing to do to raise our kids’ sights educationally to national and international standards.”

“The test itself — the measure — was not ready. Not the children. Not the teachers. [We had hoped] we would do it next year when they have worked through” the problems, he said.