He has denied the drunken driving charge and said he had not had any alcoholic drinks. Moriarty said Wednesday he might file a complaint with Washington Township police alleging an "abuse of power" by Officer Joseph DiBuonaventura, who made the arrest.
The complaints of misconduct "will be fully investigated as required by the New Jersey attorney general guidelines," township police said, declining to comment further.
Moriarty was ordered to appear in court Wednesday.
As a lawmaker, he has voted for and sponsored several bills that deal with drunken driving. He voted for a measure last year that would have reaffirmed the penalties for refusing to take a breath test.
In 2004, before Moriarty was elected to the Legislature, a state law was passed making the penalty for refusing to take a breath test suspension of a driver's license for at least seven months.
The state Supreme Court modified that law two years ago to require officers to warn drivers about the consequence of refusing the test. That prompted a follow-up bill.
That measure, approved by the Assembly Law and Public Safety Committee with a yes vote from Moriarty in November, would have forbade defendants from mounting a defense based on an arresting officer's alleged failure to state the consequences of not taking the test.
In addition, in 2009 Moriarty was the primary sponsor of a bill that would require breath or blood samples to be obtained from drivers involved in accidents resulting in death or serious injury.
He was the primary sponsor of the bill again in 2010 and reintroduced it in January.
Shortly before the Tuesday police stop, Moriarty said, he spoke to a constituent, Jacqueline Dennis of Washington Township, and visited a local car dealership.
"He was lucid and very articulate," said Dennis, a former substance-abuse hotline volunteer who spoke to Moriarty about an hour before the 4 p.m. police stop. "He was sober and his words were clear."
Moriarty said he left the United Auto Group dealership about 3:30 p.m. for the Chick-fil-A restaurant on Greentree Road and was making a left turn when DiBuonaventura pulled him over. The officer accused the assemblyman of cutting him off when two lanes merged.
DiBuonaventura "was behind me," Moriarty said. "I had my directional signal on and stopped because of oncoming traffic. I asked him, 'Why did you stop me? What did I do wrong?'
"He was irritated and said I cut him off,' " Moriarty said. "I said, 'We were merging and I was trying to make a left.' He said, 'No, you cut me off.' "
"These things happen on the road," Moriarty said Wednesday. "You probably curse someone or toot your horn, but when you have a badge, you can pull someone over."
Moriarty said DiBuonaventura ordered him from the car, asked him whether he had been drinking, and ordered him to take the field sobriety test, which Moriarty said he passed. Then he was asked to take the breath test.
A video recording of the stop was made from DiBuonaventura's squad car, township Capt. Richard Leonard said. The official police report was being prepared Wednesday.
"There was something that was read to me, but I don't recall it saying you could lose your license" if you decline the breath test, Moriarty said. It did say there could be penalties, he recalled.
The Fourth District lawmaker, who also represents part of Camden County, said he knew who DiBuonaventura was "from the start." The officer was fired from the department for allegedly being untruthful in an internal investigation, Moriarty said. He was later reinstated by court order.
Attempts to reach DiBuonaventura on Wednesday were unsuccessful.
The officer was discharged from the department in September 2009 on charges of lying during an investigation into whether he had made a racially tinged comment at a police briefing on Feb. 11, 2009. Several officers heard his remarks, including the lieutenant leading the session.
He sounded like he was making a derogatory reference about African Americans, according to some officers, but denied it. The firing occurred after Moriarty was mayor.
DiBuonaventura, of Brigantine, N.J., appealed the action to Superior Court, saying that his remark was mischaracterized and that officers had made inappropriate and racist comments in the past and were not disciplined.
Judge Richard Geiger, who sits in Cumberland County, reinstated DiBuonaventura in January 2011 and ordered back pay.
During the court battle, township attorneys argued that DiBuonaventura had been disciplined nine times in 17 years with the department.
In 2003, he was reprimanded for arresting a doctor's office manager when she refused to answer his questions after police received a complaint about her. His sergeant ordered the woman freed and said DiBuonaventura had no jurisdiction over the civil matter.
Then, in 2008, DiBuonaventura was reprimanded after telling a homeowner that the resident's complaint about a racial slur that defaced his mailbox was "not a big deal." The homeowner said the officer showed a "total lack of sensitivity.
Moriarty had his own issues as mayor. A petition was unsuccessfully circulated to recall him from the office partly because of his clashes with residents. He stormed out of several town meetings after arguing with council members.
Moriarty also had a rocky relationship with the Police Department during tense contract negotiations. Some weeks, the unions placed an inflated rubber rat in front of Town Hall.
In his exchange with DiBuonaventura, Moriarty said, he "felt like [he] was being railroaded. I was concerned about the process," he said. "I wanted guidance from my attorney from the get-go. . . . Every time he asked a question. I said, 'Officer, I'm not refusing to answer questions. I just want my attorney.' "
He refused to take the breath test, Moriarty said, because a former police chief once told him the results "could be fudged. I didn't know if I could trust the process."
The assemblyman was put in DiBuonaventura's cruiser and taken to the police station to be questioned.
"I was asked if I was diabetic, if I had any illness, if I was drinking today, and how many drinks I had," he recalled. "I said I wanted to talk with my attorney - at least 10 times."
Moriarty said officials told him talking with an attorney was not part of the process.
After his release, Moriarty reached his lawyer, who is out of the country on vacation, and asked what his advice about the breath test would have been.
"He said, 'If you talked to me, I would say, 'Take it,' " Moriarty said.
Contact Edward Colimore at 856-779-3833 or ecolimore@phillynews.com.
Inquirer staff writers Darran Simon and Barbara Boyer contributed to this article.