Bus contention when addressing tristate buffers by decoder output
If the time of contention is short, compared to the time it takes the bus to change from high to low (the fall time) or from low to high (the rise time) then the contention is not usually significant.
For example, suppose a wire in the bus has been driven to a high level by driver A. Once the wire reaches that high level then driver A is sourcing only a tiny current to keep it there. Now, if driver B starts to try to drive the wire low then driver B will be sinking a large current to change the voltage on the wire quickly. However, most of that current is from discharging the capacitance of the wire rather than from driver A. Driver A is still supplying only a tiny current at first. As long as driver A gets turned off before the voltage on the wire falls very much, the bulk of the current through driver B will be from discharging the bus capacitance (which can not be avoided) and not from contention with driver A.