I wonder what fraction of workers actually have a choice of several comparable route options.
(I'm going to get downvoted a lot for this...) - not a lot, but some.. commute is Stratford (London) -> St Pauls/Blackfriars area
* Tube, central line to St Pauls, walk
* Tube, central line to Mile End, District to Blackfriars, walk
* Tube, jubilee to London Bridge, walk
* Tube, jubilee to West Ham, Hammersmith & City to Barbican, walk
* High speed to St Pancras, Thameslink to City Thameslink, walk
* Train to Liverpool St, walk
* Train to Liverpool St, Circle to Farringdon, walk
* Train to Liverpool St, bus
* DLR to Poplar, DLR to Bank, walk
If there are no problems, you take the quickest route - but this is London, there are always problems (not least the lack of air on the central line), so a planner which actively reads delays and tells me which of the 7 ways between 25 and 55 minutes duration is the way home tonight. Sometimes you just try and get closer to the destination and see whats working in 20 minutes time...