UN R13 and UN R78 establish different brake system requirements for 4-wheel vehicles. R13H requires split service brake systems with front/rear proportioning; R78 permits split service brake systems, combined brake systems, or two separate service brake systems without proportioning requirements. Type-O dry braking tests differ: R13H requires engine disconnected at 100 km/h with stopping distance 0.1v + 0.0060 v² and MFDD 6.43 m/s²; R78 specifies multiple tests at 40, 60, and 100 km/h with varying requirements. Type-I brake fade tests use different snub protocols and performance thresholds. Secondary braking failure criteria differ at specified speeds. R78 requires wet brake testing, a 30 km/h dynamic park brake test with 18% gradient and 5 minutes hold time; R13H specifies static gradient tests. R78 includes detailed ABS, functional safety, and regenerative braking requirements; R13H does not.