When the city needs project work, we put out a Request for Proposal (RFP) in which we ask for proposals from individuals/organizations on how they would handle the job, what their qualifications are, including references, and what they would charge. Each RFP is quite specific in its conditions and each proposal must address all the issues delineated in the RFP, including deadlines.
Our decision is based not simply on the lowest bidder, but which individual/organization will do the best job for the city at the least cost.
We announce these in local media and on this site. The conditions of the response are stated within each RFP.