Commute PB clarification

1. No, I don't take a taxi, and if I did take public transport to work, it would take far longer than running.
2. I have since discovered that the distance is 7.5 km measured on Google Earth (GE). The speedo on my bike was out by a fair bit, so I re-measured the circumference and changed the settings, and now it measures the same as GE.
3. I have since run a much faster time to work: 29:50. So the previous PB is redundant now anyway.