Next time you are traveling along or trying to cross Hiawatha, take a
look at the little lights in the middle of the intersection.  They are
part of the emergency signal override system used by fire and police
vehicles.  When activated, they either are solid white or flashing
white, depending on whether the emergency vehicle is traveling the
same direction or crossing your path (don't remember which is which.)
This helps avoid crashes between vehicles both traveling under sirens.

You will notice that these are activated before the train gets near
the intersection and stay on after the train has passed.  I don't know
much about the system.  I think it's a 3M product called Opticon.
I don't know whether the system can tell what type of vehicle is
activating it or whether it can control the signals in a different
way depending on which type of vehicle it is.

So, it may be that they tried the easiest way of preempting the signals
and it isn't appropriate.  I recently came across the minutes of a
Hiawatha lrt community advisory committee meeting where Jennifer
Lovaasen, the met council communicator, told the committee that the
average delay for cars crossing Hiawatha at 46th would be 9 seconds.
Wonder if that average went over the entire 24 hours, including the
hours that lrt would not be running.

It's been said that the left turns from Hiawatha EAST have been shut
down when the override is on, which is hard to figure, given the way
that the emergency override usually works.  A fire truck was coming
from behind me last night in Saint Paul and the left trun arrow stayed
on and I was able to get out of the way.

I doubt that the lrt really affects the timing of the signals along the
route in the same way that the master traffic computer does for the
city.  There are a couple of ways that signals are usually affected by
lrt around the country.  One is preemption, which means that the train
gets a green without considering whether the cross traffic and one is
preference, which means that the train will get an earlier green or the
red will be prolonged.  The difference from here is that these are
timed to the train's actual crossing, not to the approach to the station.
Most systems where the lrt affects the intersection signals try to
smooth the transition back into normal synch with the rest of the signals
by changing the lengths of the various parts of the cycle at the
intersection, maybe shortening some and lengthening others.


Visit www.EffectiveTransit.org

The Independent Unsubsidized Voice of
Citizens for Effective Transit in the Twin Cities  (no lrt)

* lrt isn't a potato chip, you can stop at just one *

Bruce Gaarder
Highland Park  Saint Paul  MN
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