Semi-trailer brake testing

[manumartins]

Regulations about semi-trailer brake testing talk about the efficiency should be 45% of the load. But how do I measure the force applied on the periphery of the wheels?
And how do I calculate the reaction time of a brake circuit other than compressed air?

thanks

 

[EdDanzer]

SAE paper 2003-01-3397 and 2003-01-1325 may help.