Mother knows best . . .

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crr003
Posts: 575
Joined: Fri Oct 02, 2015 5:32 pm

Re: Mother knows best . . .

Postby crr003 » Fri Jan 27, 2017 12:56 pm

superplum wrote:Tsk tsk! :D
The Amber to Red cycle should last min 2secs; Red+Amber to Green - min 3 secs. Reason, provides a small delay to allow traffic to clear (theoretically).

Where are you getting these figures from? Maybe they've been changed, last time I looked the Amber phase was 3s±0.25 and the Red/Amber phase was 2s±0.25 (irrespective of speed limit).
There can also be an additional delay (all red phase).

http://www.traffic-signal-design.com/te ... y_main.htm
"Intergreen Period
The time between end of right of way for a phase and the start of the right of way for the next phase. These comprise of the 3s leaving amber for the phase losing right of way and the 2s starting red / amber for the phase gaining right of way. Depending on the geometry of the junction there may also be a period of all red to allow all traffic to clear the junction.

Intergreens must be measured carefully when configuring a junction as one that is too short can mean traffic from the previous stage is still clearing the junction when the next stage starts. Conversely, intergreens which are too long can lead to unnecessary delay within a junction which may have negative implications on the level of queuing and delay experienced at the junction."

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Horse
Posts: 2082
Joined: Mon Sep 28, 2015 9:20 am

Re: Mother knows best . . .

Postby Horse » Fri Jan 27, 2017 3:19 pm

jont- wrote: Ah yes, the network rail approach.


'Something must be done' is a wonderful thing . . .

http://www.newburytoday.co.uk/news/home ... n-a34.html

MAN who was using his mobile phone behind the wheel while driving on the A34 has been convicted of causing a crash which killed another motorist.

The collision took place near the Compton junction, when Stratford’s Vauxhall Corsa collided into the central reservation and crossed onto the opposite carriageway before colliding head-on with a BMW. The driver of the BMW, 28-year-old Gavin Roberts from Swindon, sustained life-threatening injuries and died . . .

Mr Roberts' girlfriend, Meg Williamson, subsequently started a petition demanding the whole stretch of road be reduced to 50mph and speed cameras installed to enforce the new limit.
My own views. For better or worse :)

ancient
Posts: 175
Joined: Mon Dec 14, 2015 4:03 pm

Re: Mother knows best . . .

Postby ancient » Fri Jan 27, 2017 3:42 pm

jont- wrote:
superplum wrote:Tsk tsk! :D
The Amber to Red cycle should last min 2secs; Red+Amber to Green - min 3 secs. Reason, provides a small delay to allow traffic to clear (theoretically).

Ah yes, the network rail approach. People jump level crossings, ergo we really need to increase delays to make /really/ sure everyone has cleared them. Delays get worse, more people jump the warnings, rinse and repeat. Instead just fit the train with cow catchers. 10s delay should be plenty, not several minutes. People will soon learn :bash:

In the same way skip the amber, at least when going to green. Cars will soon learn not to jump lights the other way :twisted:

Like so ? http://www.bbc.co.uk/news/video_and_audio/headlines/38750698 That'll learn'm to take notice :lol: (I think from the lack of detail, no-one was actually hurt).

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GTR1400MAN
Posts: 1366
Joined: Fri Apr 29, 2016 12:23 pm

Re: Mother knows best . . .

Postby GTR1400MAN » Fri Jan 27, 2017 3:54 pm

ancient wrote:Like so ? http://www.bbc.co.uk/news/video_and_audio/headlines/38750698 That'll learn'm to take notice :lol: (I think from the lack of detail, no-one was actually hurt).

Not relevant!

If you look the barriers are UP. Why would he not continue, trusting the lack of signals? The power had failed and because of the ice they hadn't dropped to the safe 'no power' position of down.
Mike Roberts

waremark
Posts: 593
Joined: Fri Oct 02, 2015 9:23 am

Re: Mother knows best . . .

Postby waremark » Fri Jan 27, 2017 6:21 pm

superplum wrote:Tsk tsk! :D
The Amber to Red cycle should last min 2secs;


Is this officially documented? I thought it was 3 secs in that direction?

Can the 2 sec cycle apply where the limit is 50 mph or more? Assume you are travelling at 50 mph. Using HWC figures, if you are closer to the lights when they change to red than 175 feet you cannot stop before the lights so have to continue. In 2 secs you cover about 143 feet. So if the lights change to amber when you are less than 175 feet from them but more than 143 feet you are bound to cross the lights on red.

What are the implications for driving? How do you decide on a 'stop/don't stop' decision point? Do you use maximum braking, or maximum comfortable braking? Do you make the stop/go decision every time you approach green lights: 'If the lights change to Amber now I will stop, OK now I will continue'?

fungus
Posts: 439
Joined: Sun Dec 13, 2015 5:26 pm
Location: Dorset

Re: Mother knows best . . .

Postby fungus » Fri Jan 27, 2017 7:58 pm

crr003 wrote:
superplum wrote:Tsk tsk! :D
The Amber to Red cycle should last min 2secs; Red+Amber to Green - min 3 secs. Reason, provides a small delay to allow traffic to clear (theoretically).

Where are you getting these figures from? Maybe they've been changed, last time I looked the Amber phase was 3s±0.25 and the Red/Amber phase was 2s±0.25 (irrespective of speed limit).
There can also be an additional delay (all red phase).

http://www.traffic-signal-design.com/te ... y_main.htm
"Intergreen Period
The time between end of right of way for a phase and the start of the right of way for the next phase. These comprise of the 3s leaving amber for the phase losing right of way and the 2s starting red / amber for the phase gaining right of way. Depending on the geometry of the junction there may also be a period of all red to allow all traffic to clear the junction.

Intergreens must be measured carefully when configuring a junction as one that is too short can mean traffic from the previous stage is still clearing the junction when the next stage starts. Conversely, intergreens which are too long can lead to unnecessary delay within a junction which may have negative implications on the level of queuing and delay experienced at the junction."


https://www.google.co.uk/maps/@50.73282 ... a=!3m1!1e3

At this junction the South bound traffic turning right into Vicarage Road has to cross two ahead North bound lanes with no filter light to help. The lights are partial priority on the busy Wimborne Road with a filter provided for North bound traffic turning right into Dorchester Road. Vicarage Road and Dorchester Road have full priority lights. When travelling South and turning right into Vicarage Road you have to wait for the North bound traffic to be stopped on red before you can make your turn. However, drivers from Dorchester road often go on red/amber as the last North bound vehicle clears the junction. This leaves the right turning South bound driver exposed in the centre of the junction often unable to complete their turn as the drivers from Dorchester Road drive across the front of them.

I have noticed that traffic lights in the Borough of Poole seem to only have a right turn filter if it is on a bus route. :evil:

Nigel.

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superplum
Posts: 67
Joined: Sat Dec 12, 2015 8:39 pm
Location: Above Suffolk

Re: Mother knows best . . .

Postby superplum » Fri Jan 27, 2017 8:56 pm

waremark wrote:
superplum wrote:Tsk tsk! :D
The Amber to Red cycle should last min 2secs;


Is this officially documented? I thought it was 3 secs in that direction?


Yes, I think my finger typed it the wrong way round - another few brain cells got lost today! Fungus has already quoted the reference.
:oops: :roll:

Matt1962
Posts: 108
Joined: Thu Dec 17, 2015 9:36 am

Re: Mother knows best . . .

Postby Matt1962 » Mon Jan 30, 2017 4:27 pm

I drive a lot in France and never fail to be amused by their amber phase, which seems to be set at about a millisecond. Anyone know why they have it there at all?

Matt1962
Posts: 108
Joined: Thu Dec 17, 2015 9:36 am

Re: Mother knows best . . .

Postby Matt1962 » Mon Jan 30, 2017 6:14 pm

Thinking about it, a lot of junctions have the right turn allowed on flashing amber, but I don't think the central amber is normally used for this.

Rolyan
Posts: 635
Joined: Fri Apr 29, 2016 5:45 pm

Re: Mother knows best . . .

Postby Rolyan » Tue Jan 31, 2017 1:05 pm

Horse wrote:
jont- wrote: Ah yes, the network rail approach.


'Something must be done' is a wonderful thing . . .

http://www.newburytoday.co.uk/news/home ... n-a34.html

MAN who was using his mobile phone behind the wheel while driving on the A34 has been convicted of causing a crash which killed another motorist.

The collision took place near the Compton junction, when Stratford’s Vauxhall Corsa collided into the central reservation and crossed onto the opposite carriageway before colliding head-on with a BMW. The driver of the BMW, 28-year-old Gavin Roberts from Swindon, sustained life-threatening injuries and died . . .

Mr Roberts' girlfriend, Meg Williamson, subsequently started a petition demanding the whole stretch of road be reduced to 50mph and speed cameras installed to enforce the new limit.


It's the BRAKE effect, which I can sympathise with, and understand, while knowing that it will ultimately make things worse. That however illogical, flawed and ineffective a proposal is, if its the result of grief, then no one really dare challenge it.


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