I have driven motorcycles for decades and treat heavy loads the same way Lots of room between you and the other guy and pretend no one sees you.
Those loaded cars stopped better than my all drum brake 1956 and 1957 chevy with 4 people in it.
Worst breaking car I owned had to be my 1991 Ford escort.
I talked to a friend at Ford about those brakes and he said: Yea those are some scary inefficient brakes way too small for the car.
And he said he gets those cars in all the time for brakes not stopping good.. but that was the best they would stop.
I never loaded that car down.
I had a lady run a stop sigh in Moore and I smashed my LTD 400 into the front end of that car.
Could not stop or swerve fast enough the brake pedal and my foot and her chrome Olds 98 bumper made a terrible mess of my right foot. Smashed all my toes off they were just hanging by little bits of skin.
And what you mentioned about the load keeps going ..the bike and I went over the hood of the car with me going farther.
I was 17 then. I got a bigger faster bike that stopped much better 1984 V45 Magna.
Sometimes stuff happens.