The development is completed of a new 48″ roll chassis dynamometer for 2 wheel drive (2WD) and 4 wheel drive (4WD) light duty vehicle (LDV). Overhung roll configuration onto the shaft of a hydraulic frame floated AC dynamometer is applied. Braking force measurement accuracy of PAU is ±0.1% of full scale. Vehicle traction force can be measured in high response manner without wheel torquemeter. The above and some new instrumentation architecture are reported.Digital vector controller for PAU and a new digital road load controller enabled 90% step response in 75 ms. Besides that, a dynamic road load verification method and 4WD application is reported.