Does a RAID decrease access time?

Storage device performance is described by:

• access time
• throughput is sustained average speed of data transfer.

We know that RAID0 can increase throughput, as stated e.g. here.

Access time is more tricky. Access time in a regular hard disk includes the time needed to move a read head above the target track (seek time) and the time which is needed a hard disk to bring a sector under a read head (rotational latency).

Regardless of the number of member disks in RAID 0 it may occur that the cache doesn't have a requested sector which in turn is the furthest from the read head. If this sector is needed the access time is the same (not better) as in case of a single drive. If you are willing to improve random access time you should get rid of rotational hard drives and get an Solid State Drive instead.