Crosstalk delay within an on-chip bus can induce severe transmission performance penalties. The Bus-grouping Asynchronous Transmission (BAT) scheme is proposed to mitigate the performance degradation. Furthermore, considering the distinct spatial locality of transition distribution on some types of buses, we use the locality to optimize the BAT. In terms of the implementation, we propose the Differential Counter Cluster (DCC) synchronous mechanism to synchronize the data transmission, and the Delay Active Shielding (DAS) to protect some critical signals from crosstalk and optimize the routing area overhead. The BAT is scalable with the variation of bus width with little extra implementation complexity. The effectiveness of the BAT is evaluated by focusing on the on-chip buses of a superscalar microprocessor simulator using the SPEC CPU2000 benchmarks. When applied to a 64-bit on-chip instruction bus, the BAT scheme, compared with the conservative approach, Codec and Variable Cycle Transmission (DYN) approaches, improves performance by 55+%, 10+%, 30+%, respectively, at the expense of 13% routing area overhead.