How to apply for City Permits with the Bureau of Engineering https://engpermits.lacity.org/rpermits/index.cfm
Revocable (R) Permits
A street is defined as any public thoroughfare or way, including the sidewalk, parkway, and any other public property bordering upon a public way. A street serves several purposes or uses. Primarily, it serves as a passageway for vehicles and pedestrians. The borders of streets, although in some instances not used as passageways, are still used by the public for setback purposes, and therefore should be maintained clear of obstructions where feasible.
The R-Permit is also a mechanism to utilize in special circumstances where placement of private structures out of a right-of-way would create a hardship due to topography or other restraints. Generally, private structures should not be permitted in the public right-of-way.
The purpose of the Revocable Permit (R-Permit) is to grant conditional encroachment of the public right-of-way by private parties not authorized to occupy the right-of-way. The R-Permit review process ensures that encroachments are checked for compliance with the City's specifications for design, use, material, and inspection.
The most significant factor in considering whether the City approves a request for an encroachment of any type is the status of the encroachments of other properties in the neighborhood. If there are no other similar encroachments and the proposed encroachment is significant, it may be advisable to seek neighborhood opinion by way of a questionnaire.