New-style speed cameras could become a permanent fixture in the City of London after they were credited with helping cut road deaths.
The cameras record a vehicle's average speed
The cameras, which calculate average speed over a set distance, were fixed in Upper Thames Street for 18 months to protect workers on a building site.
During their operation no-one was killed or seriously hurt on the road.
After a review the Safety Camera Partnership has applied to have the cameras turned back on permanently.
Figures showed that in the three years before they were in use, five people were either killed or seriously hurt.
The cameras were installed in 2004 as a temporary measure to protect the workforce.
But Edmund King of the RAC Foundation said that, now the building work had finished, the grounds for the cameras being turned back on had to be questioned.
He said: "If the justification was to reduce accidents when the speed was reduced, when the lanes were narrow, now we are back to normal one has to question whether the justification is still there".
The cameras could be turned back on permanently next month if the Home Office gives its approval.