Dozens of traffic police officers were mobilized at key road junctions in Attica yesterday as dysfunctional traffic lights and heavy showers caused serious problems. Some 50 traffic lights in central Athens were out of order, according to traffic police, who said things would be back to normal by Monday. There have been problems with the city’s lights since June following the expiration of the contract for their maintenance, handled by scandal-mired German electronics and engineering manufacturer Siemens. The biggest problems yesterday were on Kifissias and Alexandras avenues and Patission, Pireos, Vassilissis Olgas, Vassilissis Sofias streets and at the main junction in Halandri, northeastern Athens. The intervention of traffic police officers helped to avert widespread chaos. But a series of heavy downpours complicated their task.