I've followed the lengthy and somewhat heated discussion speculating
responsibility in the LEX accident, but I've not seen any thread on
improvements other than a few comments about traffic lights on runways,
or more people added to the system to double-check the double-checkers.
I'm interested in what the industry might do to achieve a technical
solution with relatively small front-end cost and very, very little
operational cost. (As you suspect, I have nothing to do with the
government or any of its agencies).



I find myself wondering what the cost of a low-power ground radar
capable of interpreting transponder codes, coupled to a small (not much
horsepower) computer capable of matching the geo-coords of the txpdr to
the assigned runway (or taxiway) and triggering an alarm if the variance
is too great. This should all be off-the-shelf technology, shouldn't be
considered a "flight critical" or "safety-of-flight" system (so if it
goes down for a few hours only the local information would change), and
shouldn't have to be maintained other than for hardware failures. With
the low-power and digital technology even the non-critical radar could
be maintained by break-fix only. Developed into an appliance type
system, these could be mass produced to lower the cost even more.



It seems to me that by adding traffic lights implies that we now have to
add an additional duty to the ground / flight controller which
introduces the human factor an additional time. Additionally, the
traffic light relies on the crews on parallel runways knowing which
light/runway they are really on - a seeming failure at LEX. Adding more
controllers to the system doesn't yield the best return on investment
either. Non-critical repetitive tasks should be automated where
possible.