Array is not able to improve access time

There are the following characteristics of performance of a storage system:
•    access time
•    throughput, defined as sustained average speed of data transfer.

We know that RAID 0 increases throughput. When one plans to build a RAID, only the above throughput numbers are taken into account, not thinking about access time.

Access time is made up of seek time and rotational latency where seek time is the time to move a read head to the track and rotational latency is the time which is needed for a sector to arrive under a read head. No matter how many disks are in RAID0, it may happen that the cache doesn’t have a requested sector which at the same time is the furthest from the head.
In case of such a sector is needed the access time is the same (not better) as in case of a single hard disk. The only option to decrease access time is to stick to a Solid State Drive.