Most of the traffic that could and should be on that seems to be on priority or the different agencies just key up on each others channel.
It's not really the point or purpose of 155.370 to serve as a mutual aid channel for neighboring villages or towns that have access to a countywide frequency/system or each others frequencies/systems. You shouldn't expect to hear units within OC using 155.370 to talk to each other instead of using MRD, 911 Priority, the 800 system, each other's frequencies, etc. The purpose of 155.370 is for agencies that
don't have access to a common frequency or each others systems.
Agencies within OC will use county or local systems, and agencies in Rockland will switch over to 154.725 Countywide if something goes down (including the 2F cars on the Parkway). Now, if OC cars travel into Rockland or vice versa, where they don't have access to those systems, then they would use either 155.370 or 155.475. In fact, some OC agencies have access to Rockland systems, such as Tuxedo PD, Highland Falls PD, etc., so they wouldn't have any reason to use 155.370 in Rockland either, really.