In the Scottish TMA for example:
RAC : Q)EGPX/QATXX/I/NBO/E/030/245/5543N00352W045
FROM 07/01/22 00:00 TO 07/07/31 23:59 B0064/07
E)SCOTTISH TMA DEPARTURE SPEED RESTICTION
A TRIAL OF MAINTAINING THE PUBLISHED SPEED RESTRICTION WILL BE
APPLIED TO ACFT DEPARTING ON SIDS FROM EGPF EGPH AND EGPK, CREWS ARE CURRENTLY REQUIRED TO OBSERVE AN IAS LIMIT OF 250KTS BELOW FL100.
SCACC TMA CONTROLLERS SHALL NOT CANCEL THIS SPEED RESTRICTION, UNLESS THERE ARE OVERIDING SAFETY REASONS FOR DOING SO, OR THE PILOT REPORTS THAT HE IS UNABLE TO COMPLY WITH THE SPEED RESTRICTION DUE TO THE ACFT CONFIGURATION.
THE BENIFITS SHOULD BE THAT DEPARTURE SEPARATIONS ARE MAINTAINED FOR LONGER, REDUCED BUNCHING BELOW FL100, MORE PREDICTABLE TRAFFIC FLOWS, A REDUCTION IN RTF, IMPROVE TRACK KEEPING/SID ADHERENCE AND AND IMPROVED CLIMB PERFORMANCE ON MOST ACFT TYPES