Emergency Vehicle Exemption Sensors
Matt
to use a spotlight for vehicle feedback rather then putting the green
indications into flash? I know in some other countries, flashing green
means exclusive green. This would also give standard drivers who don't
see the flashing spot light the indication to move out of the
intersection fast, without hesitation.
Paul S. Wolf
The white spotlight (or Blue lights in some places) is only an
indication to the Emergency vehicle driver that the controller has
received the preemption signal and has entered preempt mode, and is
displayed in ALL directions. If the traffic signal isn't Green, it
means that another emergency vehicle has preempted the signal also, and
thus the Emergency vehicle should use extreme caution. It isn't
intended to give any other meaning, and thus is NOT a signal indication
assigning right-of-way.
Drivers seeing the Green while a signal is in preempt mode do NOT have
to stop or move out of the way, and, in fact, should NOT do so. They
should continue moving. It's easier for the Emergency vehicle to just
follow along behind the flow, and just as effective.
--
Paul S. Wolf mailto:Traf...@aol.com
Traff-Pro Consultants, Inc.
Member, Institute of Transportation Engineers
mj...@duke.edu
> Matt wrote:
> >
> > Is there a reason why when this system was developed that they decided
> > to use a spotlight for vehicle feedback rather then putting the green
> > indications into flash? I know in some other countries, flashing green
> > means exclusive green. This would also give standard drivers who don't
> > see the flashing spot light the indication to move out of the
> > intersection fast, without hesitation.
>
> The white spotlight (or Blue lights in some places) is only an
> indication to the Emergency vehicle driver that the controller has
> received the preemption signal and has entered preempt mode, and is
> displayed in ALL directions. If the traffic signal isn't Green, it
> means that another emergency vehicle has preempted the signal also, and
> thus the Emergency vehicle should use extreme caution. It isn't
> intended to give any other meaning, and thus is NOT a signal indication
> assigning right-of-way.
In Virginia (at least the pre-empted signals on US 29 north of the city),
I believe that the spotlight is only displayed to the emergency vehicle
that pre-empted the signal. Thus, the spotlight and the green signal are
displayed...and in other directions, no spotlight is displayed. (if the
vehicle is going straight through the intersection, the green "straight"
movement is held in both directions, whereas in New York [long island],
the system isn't as sophisticated and will hold straight traffic on the
other side while allowing the emergency vehicle to go straight, left, or
right from his own direction...and no spotlights are used).
>
> Drivers seeing the Green while a signal is in preempt mode do NOT have
> to stop or move out of the way, and, in fact, should NOT do so. They
> should continue moving. It's easier for the Emergency vehicle to just
> follow along behind the flow, and just as effective.
>
I beg to differ on this for 2 reasons:
1) the average driver does not have any idea how the system works and
wouldn't know the signal is in preempt mode....the spotlight system hasn't
been around for long, i'd venture to say is not in many drivers
manuals....and probably isn't even in the MUTCD for that
matter....although it should be added in an attempt to standardize them.
2) The laws still say that drivers must yield to emergency vehicles by
pulling to the sides of the road. Often times, emergency vehicles are
traveling well over the speed limit and cars would have to move out of the
way anyway to let them pass. It might take a second or two for vehicles
to move over, but that will give the emergency vehicle a clear path. That
being said, since no cars are queued up at signals, it should be a lot
easier for them to move over.
Now that being said....I have an observation and a question:
observation: I often have the music turned up in my car and won't hear
sirens, and therefore don't notice emergency vehicles until they are
pretty close up behind me.....however I often know that there is an
emergency vehicle behind me long before I normally would when I see the
pre-emption spotlight.
question: in a system where there is no preemption devices
installed....if an emergency vehicle comes up from behind....and the
light is red....can the emergency vehicle "force" a car in front of it to
drive through a red light? I did this once, but it was in a location
where I was 100% positive that there were no red light cameras....I highly
doubt I would pass through an intersection on red if its in a place with
red light cameras like DC. I'd move over as far as I can to let them
pass, but never cross the white line :)
Matt
> to use a spotlight for vehicle feedback rather then putting the green
> indications into flash?
The times I've seen "feedback" in action has been on MA 9 in Westboro.
They use a 360 degree white strobe hanging in the middle of the
intersection. I didn't know what it was until the fire trucks went
by, just I had red and a flashing strobe.
It not only lets the oncoming units know they have green, it lets
opposing vehicles know someone else has it.
I'm anxiously awaiting a couple years from now when US 6 in my
hometown gets the Traffic Preemption system installed (it was part of
the agreement between the Town and State over the reconstruction).
It'll reduce our need for lights & sirens even more -- we don't have
that heavy of traffic usually, if you don't have traffic lights to
contend with going with the flow of traffic usually gets you somewhere
as quickly if not sooner than confusing people and dealing with dinks
who pull over on curves, hilltops, stop dead in the travel lane, etc.
John F. Carr
<mj...@duke.edu> wrote:
>
>question: in a system where there is no preemption devices
>installed....if an emergency vehicle comes up from behind....and the
>light is red....can the emergency vehicle "force" a car in front of it to
>drive through a red light?
Not in Massachusetts. You, the driver approached by an emergency vehicle,
are required to pull over to the right side of the road and stop until
the emergency vehicle has passed. You are not authorized to violate any
traffic laws other than those necessary to pull over and stop. You are
not allowed to start moving after stopping, even in order to make room
for the emergency vehicle to proceed. The law does not require you to
do anything to facilitate their movement other than driving to the right
side of the road and stopping.
Pedestrians must yield to emergency vehicles at signalized intersections,
but not at midblock crosswalks.
I don't write the laws.
mj...@duke.edu
> In article <Pine.GSO.4.50.03010...@hudson2.acpub.duke.edu>,
> <mj...@duke.edu> wrote:
> >
> >question: in a system where there is no preemption devices
> >installed....if an emergency vehicle comes up from behind....and the
> >light is red....can the emergency vehicle "force" a car in front of it to
> >drive through a red light?
>
> Not in Massachusetts. You, the driver approached by an emergency vehicle,
> are required to pull over to the right side of the road and stop until
> the emergency vehicle has passed. You are not authorized to violate any
> traffic laws other than those necessary to pull over and stop. You are
> not allowed to start moving after stopping, even in order to make room
> for the emergency vehicle to proceed. The law does not require you to
> do anything to facilitate their movement other than driving to the right
> side of the road and stopping.
thanks for the explanation. What about this situation:
An accident happens on a freeway, and traffic is stopped. The emergency
vehicles responding are using the shoulder. Do you have to pull to the
right then? If you did, that would block the very shoulder that the
vehicles are trying to use....
>
> Pedestrians must yield to emergency vehicles at signalized intersections,
> but not at midblock crosswalks.
>
That seems kind of dumb....but then again, when push comes to shove, it is
not legal for an ambulance/fire truck,etc. to run over a pedestrian, siren
or not...although it would be a nice friendly gesture for pedestrians to
yield anyway at a midblock crosswalk.
Alan Hamilton
>In article <Pine.GSO.4.50.03010...@hudson2.acpub.duke.edu>,
> <mj...@duke.edu> wrote:
>>
>>question: in a system where there is no preemption devices
>>installed....if an emergency vehicle comes up from behind....and the
>>light is red....can the emergency vehicle "force" a car in front of it to
>>drive through a red light?
>
>Not in Massachusetts. You, the driver approached by an emergency vehicle,
>are required to pull over to the right side of the road and stop until
>the emergency vehicle has passed. You are not authorized to violate any
>traffic laws other than those necessary to pull over and stop. You are
>not allowed to start moving after stopping, even in order to make room
>for the emergency vehicle to proceed. The law does not require you to
>do anything to facilitate their movement other than driving to the right
>side of the road and stopping.
Entering the intersection against the light is very risky, and it's a
bit much to expect a civilian to do it without benefit of sirens or
flashing lights on their car.
Preemption gives a green to the direction the emergency vehicle is
coming (rather than a 4-way red), so that cars may move forward to get
out of the way.
--
/
/ * / Alan Hamilton
* * al...@arizonaroads.com
Arizona Roads -- http://www.arizonaroads.com
John F. Carr
<mj...@duke.edu> wrote:
>On Fri, 3 Jan 2003, John F. Carr wrote:
>
>> In article <Pine.GSO.4.50.03010...@hudson2.acpub.duke.edu>,
>> <mj...@duke.edu> wrote:
>> >
>> >question: in a system where there is no preemption devices
>> >installed....if an emergency vehicle comes up from behind....and the
>> >light is red....can the emergency vehicle "force" a car in front of it to
>> >drive through a red light?
>>
>> Not in Massachusetts. You, the driver approached by an emergency vehicle,
>> are required to pull over to the right side of the road and stop until
>> the emergency vehicle has passed. You are not authorized to violate any
>> traffic laws other than those necessary to pull over and stop. You are
>> not allowed to start moving after stopping, even in order to make room
>> for the emergency vehicle to proceed. The law does not require you to
>> do anything to facilitate their movement other than driving to the right
>> side of the road and stopping.
>
>thanks for the explanation. What about this situation:
>
>An accident happens on a freeway, and traffic is stopped. The emergency
>vehicles responding are using the shoulder. Do you have to pull to the
>right then? If you did, that would block the very shoulder that the
>vehicles are trying to use....
The law says you must move right and stop. That's all it says.
I think a live police officer would tolerate breaking the law to
let an emergency vehicle pass -- there is a legal principle that
permits violating a law to prevent a greater harm -- but a camera
would not.
mj...@duke.edu
thats exactly why I don't like cameras. Especially after hearing reports
of emergency vehicles being cited by DC's camera enforcement system. The
company that operated them was not willing to make exceptions for
emergency vehicles since that would eat into their profits. Thus,
emergency vehicles were driving slower and refusing to pass through red
lights even with their sirens on, which boils down to slower response
times for emergencies.
>
RJ
>thats exactly why I don't like cameras. Especially after hearing reports
>of emergency vehicles being cited by DC's camera enforcement system. The
>company that operated them was not willing to make exceptions for
>emergency vehicles since that would eat into their profits.
Are we ever gonna learn that it's dangerous to allow enforcement to
profit from their efforts? It's basic human nature and economics at
work, and nothing good can come from it.
This is analogous to the property confiscation incentives in the War
On Some Drugs.
---
Bob Johnson
John David Galt
> question: in a system where there is no preemption devices
> installed....if an emergency vehicle comes up from behind....and the
> light is red....can the emergency vehicle "force" a car in front of it to
> drive through a red light? I did this once, but it was in a location
> where I was 100% positive that there were no red light cameras....I highly
> doubt I would pass through an intersection on red if its in a place with
> red light cameras like DC. I'd move over as far as I can to let them
> pass, but never cross the white line :)
An interesting question. Around here it rarely arises; if traffic is
queued and there's no preemption device, the EV will usually use the
oncoming lanes to go around the queue, then cross back to its own side
while crossing the intersection.
Steve
Just the other day, a fire engine was attempting to come down a crowded
(as usual) Western Ave. in Central Square, Cambridge, and Western Ave.
traffic was backed up in two lanes leading up to the Mass Ave. light.
Took about 45 seconds to get cars to start to hesitantly move out into
the intersection, honking, looking confused, and stopping every two feet
as if they were afraid cross traffic still wouldn't notice them. The
fire department already takes 20 minutes to go two blocks (if it even
gets the signal at all), it doesn't need extra delays. Drivers need to
be taught common sense above all else - if someone NEEDS to get through,
let them! Another one - if you face a blinking yellow, it means go
slowly, and blinking red means stop, then proceed when clear. Mass
drivers are worse than Jersey drivers.
Justin Rhodes
"John David Galt" <j...@diogenes.sacramento.ca.us> wrote in message
news:3E179DFF...@diogenes.sacramento.ca.us...
I suppose that works well on an undivided road. What if there is a median?
In Tucson (medians galore) I see ambulances getting caught in the queues of
traffic all the time.
I like the idea of designating a "fire lane" if there are three lanes in one
direction, designate the center lane as a fire lane. Then if an emergency
vehicle approaches, get the hell out of that lane, whether you pull to the
left or right.
John David Galt
>>> question: in a system where there is no preemption devices
>>> installed....if an emergency vehicle comes up from behind....and the
>>> light is red....can the emergency vehicle "force" a car in front of it
>>> to drive through a red light? I did this once, but it was in a
>>> location where I was 100% positive that there were no red light
>>> cameras....I highly doubt I would pass through an intersection on red
>>> if its in a place with red light cameras like DC. I'd move over as
>>> far as I can to let them pass, but never cross the white line :)
> "John David Galt" <j...@diogenes.sacramento.ca.us> wrote
>> An interesting question. Around here it rarely arises; if traffic is
>> queued and there's no preemption device, the EV will usually use the
>> oncoming lanes to go around the queue, then cross back to its own side
>> while crossing the intersection.
Justin Rhodes wrote:
> I suppose that works well on an undivided road. What if there is a median?
Most places I see it there is a median. The EV just crosses at the opening
preceding the backup. There's always an opening every block; California
city planners don't believe in actually having a road with long enough
divided sections that you can actually get up to a decent speed.
mj...@duke.edu
NYC has these on major avenues in Manhattan. But the problem is that when
there are vehicles lined up at a light...many times there is no room in
the adjacent lanes to clear the fire lane if cehicles in the adjacent
lanes can't move forward to create "gaps" for the vehicles in the fire
lane to move into.
My original question referred to traffic having to stop for a light where
there is clearly no cross traffic (often on older signals which are not
sensor actuated)....can these vehicles go through the red light if there
is no cross traffic to clear the way for the emergency vehicle? and also,
can an emergency vehicle ever force another car ahead of it to pass
through a red signal to clear the way (meaning can a car ever get in
trouble for refusing to pass through a red light with a fire truck behind
it, sirens and lights on, assuming there is absolutely NO other place for
this car to move to except into the intersection)?
ALmost everyone i've talked to, including volunteer firefighters and
ambulance drivers tell me that the answer to both is no. Although they
would probably look the other way if you did this to get out of the
way...you put yourself at risk since your car does not have lights or
sirens on your car....and in places with unmarked red light cameras, you
also put yourself at risk of getting ticketed....so the best thing to do
is sit tight and wait for the light to change, and as soon as it does and
you can pull forward, get
out of the way of the emergency vehicle!
Steve
I would risk a ticket to allow the emergency vehicle through. 70
dollars or whatever the fine may be is not worth what might be a life or
death matter.
mj...@duke.edu
I would risk it too so long as I knew that there were no red light
cameras. Since what cop would give me a ticket for getting out of the
way? That would be pretty harsh/tactless for a cop. But red light
cameras are a different story. If I pass through, I am 100% guaranteed to
get a ticket...and I personally don't care about life or death matters,
i'll try to move out of the way, but no way am I crossing the at stop line
until the light turns green. Computers are stupid, and its unfortunate
that they don't make allowances for extenuating circumstances such as
clearing the way for an emergency vehicle. Heck, in DC, even the
emergency vehicles themselves get ticketed according to articles posted
here way back when! How rediculous is that? If there was some kind of
guarantee that I could get out of paying a ticket for passing through to
allow an emergency vehicle through, then i'd gladly do it, but until then,
i'll move out of the way as best I can but never ever move over the stop
bar. Cities should think of this stuff before installing red light
cameras...or at least install exemption sensors at camera locations.
Alan Hamilton
>I would risk a ticket to allow the emergency vehicle through. 70
>dollars or whatever the fine may be is not worth what might be a life or
>death matter.
If you get struck by a car that has a green light when you do this,
who's at fault in the accident? Should anyone get a ticket?