Article 2. Cooperation With Cities of California Streets And Highways Code >> Division 2. >> Chapter 9. >> Article 2.

The board of supervisors of any county may, by a resolution adopted by a four-fifths vote of its members, determine that any of the following activities are of general county interest and that county aid shall be extended therefor:
  (a) The laying out, opening, construction, improvement, maintenance, repair, or altering of all or any part of any street within a city or extending along or across the boundary of a city.
  (b) The establishing, modifying or changing the grade of any such street.
  (c) The separation of the grades of any two or more such streets which intersect.
  (d) The separation of the grade of any such street from the grade of any steam, electric or street railroad crossing such street.
  (e) The construction of the necessary pavements, curbs, culverts, bridges, tunnels, subways, viaducts, drainage facilities or structures incident to or a part of such street.
  (f) The acquisition of any real property or interest therein, rights of way or other property necessary for any of the purposes mentioned in this section.

Such resolution shall specify the proposed new or existing street or portion of street, the general nature of the improvement proposed, the nature of the aid to be furnished by the county, and any funds from which the aid is to be paid.

Thereafter and in accordance with such resolution the county may give aid in one or more of the following ways:
  (a) Contribute money.
  (b) Acquire and deliver material.
  (c) Furnish labor or engineering services.
  (d) Loan its road building machinery.
  (e) Pay or contribute money to be used for the payment of interest upon, or for the payment or redemption of, bonds, the proceeds of which have been used for, or which have been issued in payment for, work mentioned in this article.

The expense of such aid may be paid from one or more of the following:
  (a) The county general fund.
  (b) The road fund.
  (c) The proceeds of any county bond issue voted for the purpose of laying out, constructing, maintaining, improving or repairing county highways or for the acquisition of any real property or interest therein, rights of way or other property necessary for such purposes.
  (d) Any other fund available for such purposes.

The city shall use all aid which it receives in the activities described in the resolution and shall return to the county any portion of such aid which is not thus used.

Boards of supervisors may enter into contracts or agreements with the legislative body of any city for the purposes specified in Section 1803.

The Legislature hereby finds that the improvement and maintenance of all city streets is of general county interest. The board of supervisors of any county may, by resolution adopted by a four-fifths vote of its members, determine that county aid shall be extended for the improvement or maintenance of streets within a city or extending along or across the boundary of a city. Such resolution shall specify the general nature of the improvement and maintenance proposed, the nature of the aid to be furnished by the county, and any funds from which the aid is to be paid. Such resolution need not specify the streets to be improved or maintained within such city but may in general terms specify the general character of the work proposed and require such reports and accounting of the expenditure of such aid funds as it may find to be necessary and convenient. The provisions of this section shall be deemed as an alternative procedure to that otherwise specified in this article.