SEATTLE (AP) — Voters in Washington state were supporting a $30 car tab initiative in early returns.

Tuesday night vote counts were showing the measure passing after the first votes were tallied in the all mail election.

Initiative 976 sponsored by Tim Eyman would decrease most taxes paid through annual vehicle registration and largely revoke the authority of state and local governments to add taxes and fees without voter approval.

Repealing existing taxes and fees could cost the state and local governments over $4 billion revenue over the next six years, according to the state Office of Financial Management.

A group funded mostly by Microsoft, Amazon, other businesses and labor unions poured nearly $5 million into opposing the initiative.

Ballots had to be postmarked or deposited in local drop boxes by 8 p.m. Tuesday. That means final results might not be known for days.