Very poor traffic management by Decmil at the West Swan road intersection. Traffic chaos caused by unnecessary lane closures. This has gone on for weeks and the traffic management people stand around watching and scratching themselves as 4 lanes of traffic attempt to merge into two at peak hour. I go through this intersection almost every day often twice a day in my truck and the closed lanes were left closed for what I can only assume was laziness and disregard for thousands of motorists. Amateurs is the most polite description I can give.