How do you select a Pilot Car provider?

I posed a question a while back to my friends in the Pilot Car industry as to how do they find their clients. The response was surprising in that most of them just wait for the phone to ring. As a OOG carrier, how do you choose which Pilot Car company to work with? Is there specific criteria you look for and a website or an industry ratings list for you to choose from?

Thank you in advance for the sharing your knowledge.