Grid Road Lighting

43399105_10160835457995034_4097097087521390592_nMilton Keynes’ unique and distinctive grid road network forms the backbone of the city’s road infrastructure. On these roads, octagonal base columns are used, with heights of 8m, 10m & 12m. On top of these are L-shaped Bracket arms, also known as “straight mitred bracket arms”, very different to the branching side-arms and circular columns used in most towns.

The original concept for the grid road lighting was for a square column which turned a sharp right angle at the top to form a side-arm. However, the decision was taken to employ octagonal columns with right-angled bracket arms instead. A few early grid roads were fitted with the branching arms and wide-based ‘hockey stick’ columns found in most other towns, namely the H1 Ridgeway at Galley Hill.

Original grid road column design with low pressure lantern. Note the square-column blue edged road signs, also a disappearing unique feature of Milton Keynes’ street furniture.

Originally, low-pressure sodium lanterns were used, between the 1970s to 1980s. These were characterised by their long, flat shape and deep orange glow. These were later replaced with high-pressure sodium, with a softer peach-coloured light, with some early examples dating from 1987 and installations continuing up to the mid-2010s. Metal halide followed from 2012 to 2014, while LED lighting has now become the norm with its characteristic bright white light.

History of Grid Road Installations

During the construction of the Grid Roads, one of two lanterns were used. The GEC Z9554M and the Eleco Golden Ray 150 saw use on many Grid Roads, examples being the V10 (including some on shorter 8m columns in the vicinity of Willen Lake), V9, V8, V7, V6, V5 and V4, usually fitted on 10m columns running 135w Low Presume Sodium (SOX) Lamps. Where 12m columns saw use, on V8, H10 and some roundabouts, the GEC Z9564 and Eleco Golden Ray 200 were the choice of lantern, running 180w Low Presume Sodium (SOX) lamps. Rare use of High Presume Mercury (MBFU) occurred on the V7 Saxon Street between Princes Way Roundabout and Brunel Roundabout on double-sided columns, using the Thorn Alpha 3, running 250w/400w.

Early ‘hockey stick’ columns with Phillips high pressure lanterns on H1 Ridgeway at Galley Hill.

High Presume Sodium lanterns first made an appearance in the 1980s with the earliest example appearing to be the H6 Childs Way around Shenley Lodge. The Urbis ZX2 was originally used, and this appeared to be used on all new Grid Roads built from this date onwards. These saw use as replacements on Roundabouts in place of Low Presume Sodium lanterns. The ZX2 saw use up to the 1990s before moving to the Philips SGS203, in use on many grid road replacement projects until 2006. After this time various lanterns were used, with new installations using stainless steel circular columns with the lantern mounted directly on top, a severe departure from the original intended appearance of grid road lighting.

The switch-off & move to white light (metal halide) 

During a period of cutbacks in 2011, the Grid Road network saw columns switched off leaving only Columns lit at Bus Stops, Junctions & Roundabouts. After complaints and issues around leaving the Grid Roads unlit, a move was made to switch the lights back on. This saw the move to ‘dimming & trimming’ with a change to white light (metal halide).  Two types of lamps were used: the CDO TT in the existing High Pressure Sodium lanterns, and the Thorn Oracle 1, running 140w CosmoPolis lamps, used across some parts of V10, V2, V3 & H4. During the period when the Grid Roads were switched off, many existing High Presume Sodium lanterns in deactivated sections were removed and used in places where Low Presume Sodium lanterns were still in use, such as the H4 Dansteed Way by Crownhill and Two Mile Ash.

During May 2014 a trial of LED lanterns saw installation on the V6 Grafton Street at Bleak Hall. Marlin Clipper 90w and TRT Aspect 131w were the choice of lanterns to be trialled. In November 2014 the TRT Aspect (95w for 10m & 131w for 12m Columns) was chosen for the replacement of the V4, V7, V8 & H8 from 2014 to 2015, with completely new octagonal base columns with shortened outreach L-shaped bracket arms. These columns replaced the stainless steel columns on new installations in a partial move back towards the original design. A move was also made to see two types of colours used, light grey for Road Columns (Grid Road and Estate Roads, out of keeping with the original concept of brown for all estate lanterns) & brown for redways.

As the LED replacement took place across the rest of the Grid Road network the choice of LED Lantern changed over to the chevron style Holophane V MAX, this becoming the choice of lantern for all major roads. Most Grid Roads including the V11, V10, V9, V6, V5, V3, V2, V1, H10, H9, H7 H6, H5, H4, H3, H2 & H1, where the new LED V MAX has seen use, have had the bracket arms changed to new shorter length.

Cropped bracket arm on new grid road installations.

Roundabouts across the Grid Road network during 2014 & 2015 saw the use of Conical columns in place of the octagonal base columns, apparently to do with crash safety. These columns supported the L-shaped bracket arms, while fitted with 140w 10m & 210w for 12m, Urbis Evolo 2 & 3 Lanterns. 2018 saw these Evolos undergo an LED gear tray convention, therefore allowing the existing lanterns to be kept rather than replacing the whole lantern head.

This is a full list of the types of lanterns which saw use on the Grid Roads from the 1970s to the 2010s:

Eleco GR200 180w SOX
Eleco GR150 135w SOX
GEC Z9554M 135w SOX
GEC Z8600 150w/250w SON
Urbis ZX2 150w SON & CDO, (250w for Roundabouts)
Philips SGS203 150w SON & CDO (250w for Roundabouts)
Wrtl Arc 90 250w SON, 150w SON & CDO
Holophane QSM 150w SON & CDO
Thorn Oracle 1 140w Cosmo 2P (Nov 2012 to July 2013)
Elgo Arcon 100 140w Philips CPO TT (Jan 2014 roundabouts)
Marlin Clipper 90w LED (installed on test V6 Bleak Hall)
TRT Aspect 131w LED (installed on test V6 Bleak Hall)
Philips Wrtl Arc 80 150w CDO TT (Oakgrove Brickhill Street)
Holophane QSS 150w CDO TT (August 2014)
Philips Wrtl Arc 80 140w Cosmo optic 2pin (October 2014)
Urbis Elovo 2 140w Cosmo Nov 2014 Roundabouts
TRT Aspect 131w & 95w LED
Holophane V MAX 90w LED