In what is believed to be a nationwide first, an entire shift in a specialist Metropolitan Police unit has been staffed by special constables.
Scotland Yard said that the initiative allowed the regular team to be re-tasked to a different operation, targeting the seizure of illegal vehicles.
"Specials" have the same powers as regular officers, but give their time voluntarily and are not paid.
Acting Superintendent Ray Rogers said: "This initiative really highlights the fact that specials have the same responsibilities and powers of regular officers and can be relied upon to deliver results."
The Traffic Operational Command Unit dealt with 26 incidents on that day, including:
Stopping and arresting a suspected burglar who was trying to make an escape.
Bringing a motorist to safety after a serious crash on the A40.
Chief Superintendent David Snelling said: "Some [special constables] have specialist skills from their "day jobs" that are relevant to our field of work, such as engineering, collision investigation and law, which enables them to provide similar specialist support to that of their regular Traffic colleagues but far more important is their enthusiasm to get involved."