Police cannot use radar to catch speeders on the downtown Hayward one-way traffic loop until all construction is complete, including landscaping, police told merchants this week.

Any time a road is altered, a new traffic survey is required before police are allowed to issue tickets with radar, Lt. Mark Koller said Thursday during a regular monthly meeting at City Hall. Otherwise, the tickets could be challenged in court.

Downtown merchants have complained that traffic is speeding through the area since the loop began in March.

There was no estimate on when a new survey could be completed. When asked what could be done to nab speeders in the meantime, Officer Leon Limon said officers could use pacing and visual estimates of speed.

While work is almost done on the loop, some things remain to be done, including painting of some crosswalks, installation of street signs, landscaping and adding a pedestrian barrier railing in the median by Five Flags Park, said Kevin Briggs, city project manager for the roadwork. He estimated it would be finished in a month or month and a half.