Israel’s Supreme Court ruled on Tuesday that a major access highway to Jerusalem running through the occupied West Bank could no longer be closed to most Palestinian traffic.

In a 2-to-1 decision, the court said the military overstepped its authority when it closed the road to non-Israeli cars in 2002, at the height of the second Palestinian uprising. The justices gave the military five months to come up with another means of ensuring the security of Israelis that permitted broad Palestinian use of the road.

“The court was saying that you can’t reasonably find every Palestinian inhabitant to be a security risk,” said Moshe Negbi, a legal commentator for Israel Radio, in a telephone interview. “The security considerations are legitimate, but they have to find other solutions.”

The closely watched case, argued by the Association for Civil Rights in Israel, was brought by a half-dozen Palestinian villages where land was expropriated for the road and inhabitants were barred from using it.

When the land was confiscated three decades ago, the villages objected, saying they had no interest in a new road. But the military contended that the villages would be the main beneficiaries of the highway, and the court yielded to that argument, saying occupied land could be developed for the benefit of those living there, not for the occupiers.

But once the uprising began, there was stone-throwing and shooting on the road. In 2001, five Israelis were killed there by gunfire, and the military cut the highway off to West Bank Palestinians, placing huge boulders between the Palestinian villages and the 13 miles of road. Meanwhile, as Israel grew more prosperous and traffic between Jerusalem and Tel Aviv heavier, the road, known as Highway 443, became a major alternative to Israeli commuters. About 40,000 cars use it every day.

Palestinians who live in Jerusalem, while not Israeli citizens, carry Israeli identity cards and drive cars bearing Israeli plates, so they have been able to use the highway.

Limor Yehuda, the lawyer who argued the case for the civil rights group, said she hoped the court would apply the ruling to all segregated roads in the West Bank to end the dual system there.

“We can see that as a society we are going in the wrong direction and endangering our basic values of a rule of democracy and rule of law,” Ms. Yehuda said.

But it was not clear that the court would apply the ruling broadly. In some later seizures, the army took land for separate roads, contending that its motive was security, not the benefit of the local population.

Ms. Yehuda urged the military to put the ruling into effect as quickly as possible, saying the Palestinians’ freedom of movement was “a right which has been severely infringed on for nearly a decade.”

She had told the court that the rise of segregated roads in recent years approached apartheid, but the chief justice, Dorit Beinisch, chided her for using that term, calling it inappropriate and extreme.

In the past two years, Palestinian violence has subsided substantially, and most roads on the West Bank have been opened to both Israeli and Palestinian cars. But about 100 miles of roads there remain closed to cars bearing Palestinian license plates.

The dissenter in Tuesday’s case, Justice Edmond Levy, argued that the court should leave the situation in the hands of the military and the Defense Ministry, and worried that five months would not be enough time to create a new system.

Israeli settler leaders expressed alarm at the court’s decision, saying it would endanger Jewish travelers. They contended that the justices “never missed an opportunity to blame Jews for racism and provide Arabs with convenient conditions for the next terror attack.”

As peace talks between Israel and the Palestinians remain stalled, the threat of violence has risen slightly. Last week, an explosive device made from a gas canister and fireworks was found on Highway 443.