Flight Crew Air Transport Pilot (ATP)
Situational Awareness
ATC Issue All Types; Conflict Airborne Conflict; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew FLC complied w / Automation / Advisory; Flight Crew Took Evasive Action
Human Factors; Procedure
We were cleared to descend to 11;000 feet on the LAS SUNST3 arrival.  During the descent; we received a traffic warning and RA as another aircraft was given an unrestricted climb to FL190 on the LAS SHEAD8 departure; which deviated from the published speeds and altitudes.  We were descending through 2;500 feet when we got the alert.  The traffic was close enough for me to identify that it was another EMB175.  The First Officer took evasive action and followed flight director guidance and adjusted vertical speed to avoid collision.  This was a result of ATC issuing a clearance that deviated from published altitudes and speeds; which in turn caused the RA.  Had the departure been flown as published we would have crossed with 2000 feet clearance of the other aircraft.  Instead; we were descending at 1500fpm as another aircraft with an unrestricted climb; was climbing at approximately 3000fpm giving a 4500fpm closure rate; which caused the RA.  The RA was reported to ATC.  We landed without incident.
An EMB-175 Captain on descent into LAS reported a conflict with another EMB-175 who was departing LAS. The reporter stated he believed the ATC clearance precipitated the event.