SACRAMENTO, Calif. (AP) — Opponents of California's $68 billion high-speed rail project are appealing to the state Supreme Court, asking the justices to overturn a lower court ruling that allowed the project to proceed.

In a petition submitted Tuesday, Central Valley residents argue that the July 31 appellate court ruling undercuts 100 years of precedent requiring the state to strictly comply with promises made in ballot measures.

They argue the current bullet train plans violate terms of the 2008 ballot measure, when voters approved selling nearly $10 billion in bonds.

Proposition 1A promised that the state would identify funding for the first useable stretch and have environmental clearances done before starting construction.

A lower court judge ordered the state to write a new funding plan, but the appellate court said the challenge was premature.