A driver can affect the time on a run by the way he/she does the following:
1. Burnout
2. Clutch/brake control during backing up, putting car in forward and reverse, going to stage.
3. Consistency in his timing to do the above.
4. Aborting a run before major damage if something isn't right.
5. Staging, in regards to time to stage, how far into a light (referred to "grabbing/taking a chunk", foot too heavy on throttle during which raises the pre set rpm,
6. putting throttle all the way down quickly and staying all the way down throughout the run.
7. Keeping car going straight and preferrably in the groove.
8. Slapping throttle or pulling brake to limit spin or shake, or staying away from both to allow your TCD to do it's job (if installed)
Not saying Johnny has a problem with any of this, just what the driver can screw up on a run.