Dear 運輸署,

Thank you for the reply of my request on Oct. There are further questions about the traffic light system that I would like to ask.

1. You mentioned that the loop detectors on the traffic lanes can help allocate signal time 
automatically according to the actual traffic condition. Can you explain more detail about under what situation the signal time will change automatically?

2. Under what condition the traffic signal plans and settings will be change through the real time remote control by the control centre? and is it changed individually or a sequence of traffic signal will be changed concurrently?

3. We would like to know the d of the data of junctions including the cycle time, the sequence and also duration of green and red light. Also, is there any sequence between these junction?
Below are the junctions that we would like to have:
- junction of Nathan road & Jordan road
- junction of Nathan road & Gascoigne road & Kansu street
- junction of Nathan road & Austin road
- junction of Austin road & Cox's road & Pine Tree Hill road
- junction of Austin road & Chatham road South & Cheong Wan road
- junction of Jordan road & Gascoigne road & Queen Elizabeth Hospital road
- junction of Jordan road & Cox's road
- junction of Gascoigne road & Wylie road

Regards,
Zoey Tsang

27/12/2018

Subject:Freedom of Information request - Current traffic light system in Hong Kong (Case Ref: 2-4962077493)

Dear Zoey,

Thank you for your email to the Transport Department dated 26/12/2018. Please note that 1823 of the Government helps the Transport Department receive public enquiries and complaints via its e-mail box "[Transport Department request email]", telephone hotline "2804 2600" and fax hotline "2804 2652".

We have referred your case to the Transport Department. You will be informed of the outcome as soon as possible.

If you have any enquiries, please contact us.

Best regards,
Viola Tong
Customer Service Officer
1823

Tel: 1823
Fax: 2760 1823
Email: [email address]

(For effective handling of your case, all our conversations may be recorded, irrespective of whether you dial in or we call you back.)

Dorothy Shuk Kwan CHIM, 運輸署

2 Attachment

Dear Ms Tsang,

I refer to your email dated 26.12.2018 requesting for information on the
traffic light system in Hong Kong.  Our reply to your request is as
follows.

Q1. You mentioned that the loop detectors on the traffic lanes can help
allocate signal time automatically according to the actual traffic
condition. Can you explain more detail about  under what situation the
signal time will change automatically?

A vehicle-actuated signal responds to demands received by various loop
detectors for the various directions of traffic flow on road.  On the
approach to a red signal, a green signal will be demanded on the arrival
of a vehicle on that approach.  When a green signal is displayed, the
period for which it is displayed may be extended by vehicles detected
moving towards the signal until all the vehicles have passed through the
junction, or the maximum green times for that direction has timed out.  On
expiry of the last extension and no more vehicles are detected, the signal
controller will answer a demand of another stage.

Q2. Under what condition the traffic signal plans and settings will be
change through the real time remote control by the control centre? and is
it changed individually or a sequence of traffic signal will be changed
concurrently?

Pre-determined multi-plan setting will be adjusted on a need basis as
follows:

* To meet the changes in traffic patterns or demands of traffic
following the traffic review.
* To suit temporary traffic situations such as road works and race
meetings.
* In case of emergency, request from the Police.

Adjustments to signal stage times, green splits or linkage of signal
groups and introduction of special plans can be applied from the control
centre.  The adjustments or changes in signal plan timings or linkage of
signal groups could be applied at respective signalized junctions
individually.

Q3. We would like to know the d of the data of  junctions including the
cycle time, the sequence and also duration of green and red light. Also,
is there any sequence between these junction? Below are the junctions that
we would like to have:
- junction of  Nathan road & Jordan road
- junction of Nathan road & Gascoigne road & Kansu street
- junction of Nathan road & Austin road
- junction of Austin road & Cox's road & Pine Tree Hill road
- junction of Austin road & Chatham road South & Cheong Wan road
- junction of Jordan road & Gascoigne road & Queen Elizabeth Hospital road
- junction of Jordan road & Cox's road
- junction of Gascoigne road & Wylie road

The requested information is attached.  The cycle time and duration of a
stage in each junction can be adjusted individually.

If you have any enquiry about our reply to Q1 and Q2, please contact Ms
Chu at 2829 5359 or by email ([email address]).  If you have any
enquiry about about our reply to Q3, please contact Mr Leung at 2782 7812
or by email ([email address]).  

Thank you.

Yours sincerely,

Miss Dorothy Chim
for Commissioner for Transport

show quoted sections