| 1.4.4.2. | With the exception of cases according to paragraphs 1.4.4.3. and 1.4.4.4. of this annex, it is necessary for the determination of the braking rate of the trailer to measure the braking rate of the towing vehicle plus the trailer and the thrust on the coupling. The towing vehicle has to meet the requirements laid down in Annex 10 to this Regulation with regard to the relationship between the ratio TM/PM and the pressure pm. The braking rate of the trailer is calculated according to the following formula: | a0c0 |