 Crowded out - BBC News
>
> This, of course, is the charge often levied against road building. That
> said, in a sense I cannot see why it would not be the case where you add
> capacity to any transport system, it will end up being used more
> assuming the means to use it (economic growth) allows it.
>
> So are there any differences between guided/railed transportation and
> unguided in this regard?
>
As a general rule once a road fills up there's not much you can do to
increase capacity. In fact, the more congested roads are the ones that
end up having more traffic control measures applied to them such as
traffic lights, roundabouts and the dreaded bus lane all of which help
on capacity but not on journey time.
Railways can be much better at accommodating traffic growth, longer
trains, higher frequency are all options available.
If demand gets really high then double deck trains can work wonders.
For example, the French TGV has been highly successful but has yet to
become a victim of its own success thanks to things like double deck
TGVs.
It's amazing just how much traffic can be pushed down two tracks if
you really try.
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