The Los Angeles City Council passed an emergency ordinance Friday banning new digital billboards, supergraphics and other outdoor advertising signs from most areas of the city.

The council’s 12-0 vote came in response to a legal challenge from Liberty Media Group to an existing moratorium. That challenge is set to be heard by a federal judge on Aug. 17. As an emergency ordinance, the ban took effect immediately in an attempt to pre-empt an unfavorable court ruling.

Several councilmembers feared that if Liberty Media’s challenge prevails and the moratorium is struck down, hundreds of applications for new billboards and building-covering supergraphics would pour in. The emergency ban is aimed at preventing this from happening.

The council had repeatedly extended the year-old moratorium while the city crafted new rules for outdoor advertising signs. The rules would ban new digital signs and supergraphics in many areas of the city, but would allow the signs in 21 special districts, including downtown and Hollywood.

These rules also would have placed restrictions on new signs placed on property advertising or identifying on-site businesses, raising concerns from local business groups that companies would be unable to advertise their presence.