Traffic (causing) police officers

Is it just me? Or has anyone ever noticed that there are heavy traffic jams on the Regional Road heading from the University to St Julians (and back) only when there are traffic policemen on duty at the "Palm Tree" roundabout?

It seems that when they are not there everyone seems to get on just fine and traffic, although slow at times, never grinds to a halt.

Every morning I drive through the Sta Venera tunnels towards St Julians heading for work.

As I cross the Valley Road Bridge I can normally tell at a glance that there are traffic policemen down by the roundabout (over a mile away) as nothing is moving.

If they are there, there is normally chaos and traffic is practically at a standstill from the roundabout all the way to the Sta Venera tunnel.

On the days they don't turn up, it is much faster and I get to work on time!

Do they realise that we don't need their "services" or do they just do it on purpose to add a bit more stress to our already hectic lives? I sometimes wonder.