In this paper, we present the investigation of the traffic load measurement mechanisms and their performance impact on an ATM switch in presence of VBR traffic. We first categorize those mechanisms employed by a number of switch algorithms into two main schemes: Arrival Cell Counter Based (ACCB) and RM Cell Information Based (RCIB). In this investigation, ABR traffic is affected by higher priority traffic, e.g. VBR traffic. We use three types of sources to generate VBR traffic: ON-OFF, exponential distribution, and MPEG video. We then evaluated the scheme performance by using computer simulation. The simulation results have shown some limitations, their trade-offs, and performance effectiveness of such schemes. We have proposed our scheme, which can be employed by the switch to maximize its performance. We have shown the results through computer simulation, in most case, the proposed scheme performs better than those schemes.