Twenty hours past, here is my academic guess,

the origin of any transportation service firm is vulnerable, (unverified business model, weak credibility and limited transportation network).

Based on the upper assumption, the most reliable expanding way is to utilize other's network and transportation capability.

I  don't know the list, however, I believe majority of delivery service firms are on the list, especially at their early stage of development.

Wal- mart, Federal express and FedEx.
I hope this helps.
Thanks.