The car should be at approx. 1 bar at idle after warming up. I believe the allowable value is just under 1 bar at idle once warm. The pressure should jump to 3 bar after rpms hit approx. 1500.
At highway speed the pressure will also be 3 bar.
1 bar is about 14.5 lbs. 14.5 x 3 = about what you'd see in a domestic at highway speed.