PLEASANTON -- A road-rage confrontation nearly ended in tragedy when a 61-year-old man pulled out a sword concealed inside a cane and stabbed the side of another driver's car Friday afternoon, police said.

The sword did not penetrate the interior of the car, and the other driver was not injured, though the man who wielded the sword may have cut his hand, according to Pleasanton police Lt. Jim Knox. The suspect, Pleasanton resident Sam Cangiamilla, was arrested on suspicion of assault with a deadly weapon at his home about two hours later.

The confrontation began around 4:50 p.m. on eastbound Interstate 580 near Dublin, Knox said. The 42-year-old male victim told police that Cangiamilla was switching back and forth in lanes, attempting to block him from passing.

The victim got off the freeway at the Santa Rita Road exit, and got out of his car at a red light to confront Cangiamilla and ask why he was following him. Cangiamilla then got out of his car and produced an object later identified as a sword hidden inside a cane, Knox said.

The victim saw the sword and got back into his own car, fearing for his safety. Cangiamilla stabbed at the man's door, puncturing it with the sword, Knox said.

Cangiamilla got back into his car, taking the sword with him, and drove away while the victim followed, Knox said. The victim reported Cangiamilla's address, on Del Sol Avenue, to the police.

When an officer arrived at the home, Cangiamilla spotted the police car and headed inside the house before the officer had a chance to speak to him. Police tried several times to contact him over the phone before he answered, and he voluntarily came out of the house and was placed under arrest for suspicion of assault with a deadly weapon around 6:50 p.m., Knox said.

The sword, which Knox described as a prohibited "disguised" weapon, was recovered at the home.

Cangiamilla declined to comment when reached by phone Tuesday.

Police are still investigating and the case has not yet been submitted to the district attorney's office, Knox said.

Contact Daniel M. Jimenez at djimenez@bayareanewsgroup.com. Follow him at Twitter.com/DMJreports.