Intelligent Speed Adaptation
(ISA) is one of the most promising Intelligent Transport
Systems in terms of its potential impact on safety.
It is a system by which the vehicle "knows"
the permitted or recommended maximum speed for the road.
The standard system uses an in-vehicle digital road
map onto which speed limits have been coded, combined
with a positioning system which could be GPS, i.e. the
satellite Global Positioning System, but could also
be GPS enhanced with map matching and dead reckoning.
ISA can take various forms:
In terms of intervention level, it can be:
| Advisory ISA: |
the driver is informed
of the limit and of violations but there is no direct
link between this information and the vehicle controls |
| Voluntary ISA: |
the system is linked to the vehicle
controls but the driver can choose when to have
the system enabled |
| Mandatory ISA: |
no override of the system is possible |
The speed limit information can potentially be extended
to incorporate lower speeds at certain locations in
the network and even in the future variation with current
network conditions, based on weather, traffic density,
the presence of incidents etc.
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