Haredi men looked at her askance but made no protest. On the second stop a haredi man boarding stopped inside the door and asked if she would move to the back. "No, I won't," she said.
After a brief exchange, she put on earphones and listened to music. At one point, when the man shouted at her, she took off the earphones and stated her case.
"There's no cause for behaving this way to anyone, certainly not women. I made no provocation. I bought a ticket like you did. You won't tell me where to sit only because I'm a woman. I'll sit where I please."
She held her ground despite an angry crowd of haredi men that had formed outside.
The man continued to block the door and said he would do so until the woman moved. After half an hour, the driver called the police.
The policeman attempted first to persuade the man to desist, then asked Rosenblit if she would mind, out of respect for their ways, moving to the back. She refused.
At that point, the haredi man got off and the bus continued. Rosenblit related the incident on her Facebook page and it was soon the big story in the country. Editorial writers were reminded of Parks, the black American whose refusal to go to the back of the bus in Montgomery, Alabama, in 1955 was a landmark in the civil rights movement.
Recently the haredim have tried to impose an increasingly fundamentalist lifestyle within their own sector, at one point putting a curtain down one of the streets in Jerusalem's Mea Shearim neighbourhood to keep males and females separated during a festival. This tendency has begun to spill out into the broader community.
Haredim serving in the army - a small but growing numbers do - have begun to walk out of military ceremonies if women sing. In Jerusalem, where haredim are a significant portion of the population, advertisers have learned to display women on posters, if at all, in demure dress.
Rosenblit's Facebook report drew hundreds of responses. One group announced yesterday that a nationwide protest action would be held on January 1 when groups of 10 women and men would board buses serving haredi communities around the country and demonstratively sit in the front.
In the Knesset, Opposition leader Tzipi Livni said Rosenblit's "perseverance represents the need of everyone fearing for Israel's character to fight and not give up."
Chief Ashkenazi Rabbi Yona Metzger said: "We [the ultra-orthodox] don't have the authority to force our ideas on others."
Prime Minister Benjamin Netanyahu called for mutual respect between all sectors, including Arabs and Jews, religious and secular.