Not everyone on public transport would have driven

I saw a press release from the government's uber agency on land transport (set up by the Clark Administration to get rid of the funder-provider split that saw decisions split between government agencies, making them difficult to control directly) New Zealand Transport Agency that seemed otherwise innocuous.

It is about a series of bus lanes opening in Christchurch on the main highway south of the city (curiously it links to a website that hasn't been updated since 2010 -  Christchurch has changed since then, and there is no map of the lanes actually opening - well done).  I'm not particularly objecting to the bus lanes, they may well make sense here.  What caught my eye was this absurd statement:

"A full bus equates to 40 fewer cars on Christchurch roads"

Pardon me, but this is unadulterated bullshit, whatever way you look at it.

Even if we assume that a full bus really is a full bus (people seated and standing), it might at best have 70 or so passengers.  The only way it could mean 40 fewer cars on the roads is if everyone on that bus would have driven a car or ridden in a car with someone on that bus.

That assumption is quite ludicrous.  

If a bus doesn't operate, there are two broad options for the user.  Travel by another means or don't travel at all (which can include changes in destination).  To assume all bus users would drive, or ride a car driven by someone on the bus is nonsense.   

Yes, some would.  

However, some would catch a ride with someone who is already driving.   That isn't adding a car to the road.

Some may bike, some may walk. Both of those options are environmentally preferable to the bus.

Some will decide not to travel at all, and may undertake the trip purpose elsewhere.  In the longer term, it may mean people relocate to a place closer to work, or choose a different job.  Not all trips occur regardless.   It is false to presume all bus trips are commutes.

In other words, to grossly simplify transport mode and trip choice options as being "catch public transport or drive a car" is to exaggerate the importance of public transport.  It is one option.  It can attract people from driving, but many users are those for whom driving isn't a reasonable alternative in any case.

If people are attracted from cars to buses, then all well and good.  Given the bus companies and their passengers are getting allocated a third of the road "for free", you'd hope it does work.    However, let's not pretend buses are full of otherwise drivers.  

Of course in Auckland it's even more ludicrous, because there it is trains that in part attract people from buses - but that is an uncomfortable fact the railevangelists would prefer to sideline - that many of the people riding public transport are not people who would otherwise hop in their own cars and jam up the roads, but people who wouldn't travel otherwise (and are getting a heavily subsidised trip for the privilege).