From the FAA:
SMES (Surface Movement Event Service): ASDE-X/ASSC data, OOOI events (Spot Out, Off, On, Spot In), Category 11/Category 10 position reports.
ASSC improves surface surveillance and situational awareness in all kinds of weather. ASSC is similar to a prior system deployed in the U.S. called the Airport Surface Detection Equipment, Model X (ASDE-X), which is deployed at 35 airports.
In October 2016, ASSC will be operational at San Francisco airport. Over the next few years, it will be implemented at:
https://www.faa.gov/nextgen/programs/adsb/atc/assc/
It appears that the system referenced for the aircraft location and altitudes was the first of its type installed by the FAA.... Did this new system provide warnings of the conflict?
Since the new and improved system does not appear to have detected the conflict, what about its predecessor which is deployed a minimum of 35 airports in the US, and an unknown number of airports worldwide?
here we go, a few more holes in the Swiss Cheese ...
EDIT: 35/36 airports for ASDE-X....
http://saab.com/saab-sensis/air-traf...gement/asde-x/
Following the success of the ASDE-X program that covers 35 airports in the USA, the FAA decided to extend the technology to nine additional airports: Anchorage, Andrews Air Force Base, Cincinnati/Northern Kentucky, Cleveland, Kansas City, New Orleans, Pittsburgh, Portland, Ore and San Francisco.
The ASSC system deployment includes multilateration sensors, data fusion, conflict detection and alerting, and the same HMI already in use at the 35 ASDE-X sites.