1. DAYTIME DIMMING PHOTOCELL © Radix Traffic Limited 2012Patent Applied For THE RADIX TRAFFIC INTELLIGENT DAYTIME DIMMING UNIT (IDU600)

2. DAYTIME DIMMING THE CONCEPT © Radix Traffic Limited 2012Patent Applied For  UK traffic signals are bright during the day. This is to ensure visibility when the sun is low in the sky or on very sunny days.  This makes them too bright at night, so in most areas of the country they are dimmed to about 25% of their ‘bright’ level using a conventional plug in photocell.  A lot of the time however, the UK weather during the day is overcast and dull.  When the weather is overcast and dull, signals do not need to be at full brightness to be seen clearly.

3. DAYTIME DIMMING THE BENEFITS © Radix Traffic Limited 2012Patent Applied For  Met Office data shows that ambient light levels in the UK fall below 10,000 Lux on average for 38% of daylight hours.  A dimmed traffic signal under these conditions is at least as visible as a bright signal against a sunny summer sky (40,000 Lux).  Daytime dimming of traffic signals can realise an energy saving of between 15% and 25%. The Radix Traffic IDU600 photocell provides the intelligence to monitor daytime light levels and dim signals both day and night.

4. HOW THE IDU600 WORKS © Radix Traffic Limited 2012Patent Applied For

5. THE IDU600 – DEVELOPMENT SIMULATOR TRIALS © Radix Traffic Limited 2012Patent Applied For  To investigate whether drivers respond differently to daytime dimming, with the agreement of the DfT and the Highways Agency, the Transportation Research Group at Southampton University have undertaken extensive trials using their driving simulator.  The trials were undertaken using drivers of different age groups and genders, driving both rural and urban routes comprising several traffic signal junctions and crossings both bright and dim. Southampton University’s report from the trials concludes: “ ….. there is no significant difference in driver behaviour between the bright and dim signals ….”

6. THE IDU600 – DEVELOPMENT SIMULATOR TRIALS © Radix Traffic Limited 2012Patent Applied For

7. THE IDU600 STREET TRIALS © Radix Traffic Limited 2012Patent Applied For  Since the successful trials at Southampton University, Radix Traffic have now completed the cell hardware and software development and have manufactured a number of 48V (ELV) and 230V (LV) units.  The Highways Agency have given Radix Traffic the approval to undertake trials on street in accordance with TRG 0600 Issue A. Radix Traffic Limited would welcome support from Local Authorities who would like to host a small number of trial sites for the purposes of the TRG 0600 A trials approval process.

8. ACHIEVING THE BENEFITS © Radix Traffic Limited 2012Patent Applied For  The IDU600 is easy to fit. The existing photocell is unplugged and the new one plugged in. Commissioning requires that the cell is covered briefly then uncovered to confirm operation.  Sites can be upgraded during routine preventative inspection visits to avoid additional maintenance visits.  To benefit from the energy savings from the electricity supplier a dedicated dimming/switching regime code will be issued by Elexon.  The signals energy use inventory can then be amended to show the new switching regime.

9.  Dimming regime comprises of two modes of operation: 1)Identical with the current dawn/dusk switching regime 2)Permits switching during daylight hours when specific criteria are met.  Designed to work with all existing traffic control systems, requiring only the selection of a 230V ac or 48V ac variant for LV and ELV sites respectively.  Simple replacement of the existing photocell (using the standard cell socket).  15%-25% energy savings per annum. To realise the benefit,  15%-25% energy savings per annum. To realise the benefit, when reporting the energy use of their traffic signals equipment, Local Authorities will need to use the Elexon coded dimming regime for the new photocell sites.  Payback approximately 3-4 years for sites with mainly halogen signals.  Payback approximately 5-7 years for sites with mainly LED signals. SUMMARY © Radix Traffic Limited 2012Patent Applied For

10. THANK YOU FOR YOUR ATTENTION For more information, please contact: Brian Cherry, Managing Director Radix Traffic Limited Tel: 01794 511388 Mobile: 07824 827478 E-mail: cherryb@radixtraffic.co.uk