SEATTLE (AP) — A judge on Wednesday blocked Tim Eyman’s $30 car tab measure from taking effect in Washington state while cities and counties challenge its legality, citing “substantial concerns” that the initiative’s description on the ballot was misleading.

Voters approved Initiative 976 earlier this month.

It caps most taxes paid through annual vehicle registration at $30 and largely revokes the authority of state and local governments to add new taxes and fees.

The city of Seattle, King County, Garfield County’s transit agency and a coalition of cities across the state sued to stop the measure.

They argue that the ballot summary said I-976 would “limit annual motor-vehicle-license fees to $30, except voter-approved charges.”

The plaintiffs say that suggested to voters that locally approved measures, such as additional license fees passed by Seattle voters to pay for improved bus service and voters’ agreement to fund Seattle-area Sound Transit light rail projects, would survive.

As the full text of the measure shows, however, only fees approved by voters in the future would be allowed, and the authority of local jurisdictions to seek such measures to begin with would also be curtailed.

King County Superior Court Judge Marshall Ferguson expressed concern during a hearing Tuesday that language was misleading, and in his order Wednesday he said the plaintiffs were likely to win their case.

He ordered Washington state to cease efforts to implement the initiative on Dec. 5, when it was due to take effect, pending further orders.

The judge emphasized that he had not reached a final determination that the measure is unconstitutional.

He noted, however, that if the state and cities continue to collect the vehicle taxes and fees as they have been, they can later refund that money if the initiative is upheld.

But if they stop collecting the money while the case proceeds, there’s no way for them to collect them retroactively.