PLS 2016: ILP Technical Committee latest expert guidance & documents – PLG08
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Meet the brains behind one of the ILP’s latest key documents: PLG08 Guidance on the application of adaptive lighting within the public realm Talk by Nigel Parry, ILP Technical Committee
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PLS 2016: ILP Technical Committee latest expert guidance & documents – PLG08
- 1. #ILPSummit Technical Committee latest expert guidance and documents • PLG08 Guidance on the application of adaptive lighting within the public realm #ILPSummit
- 2. #ILPSummit PLG08 Guidance on the Application of Adaptive Lighting within the Public Realm
- 3. #ILPSummit
- 4. #ILPSummit
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- 6. Ultra-Efficient Lighting (UEL) The adaptive lighting approach will essentially look to help enable you to apply the principles of Ultra-Efficient Lighting (UEL) which is defined as: “Providing the • right light, in the • right place at the • right time and controlled by the right system”. #ILPSummit
- 7. BS5489-1:2013 for the five step design process, the steps being as follows: Step 1 Select lighting class Step 2 Risk assessment Step 3 Adjust lighting class Step 4 Consider S/P ratio Step 5 Consider adaptive lighting BS5489-1:2013 #ILPSummit
- 8. Comparable lighting classes based on BS5498-1, 2013 ME Class CE Class S Class Required average illuminance (lux) % dimmed compare to above class - CE0 or C0 - 50 - ME1 or M1 CE1 or C1 - 30 40% ME2 or M2 CE2 or C2 - 20 33% ME3 or M3 CE3 or C3 S1 or P1 15 25% ME4 or M4 CE4 or C4 S2 or P2 10 33% ME5 or M5 CE5 or C5 S3 or P3 7.5 25% ME6 or M6 - S4 or P4 5 33% - - S5 or P5 3 33% - - S6 or P6 2 33% #ILPSummit
- 9. Adjusting the lighting class The British and European Standards allow illumination levels to be varied depending upon the category of road and its usage. Therefore illumination levels could be reduced when traffic flows are lower. Lighting could also be increased as a crime reduction measure, say outside night clubs for a defined period after they close. #ILPSummit
- 10. What is adaptive lighting? The term used do define the operation of the lighting during the periods of darkness. It includes: • Compensation for design maintenance factors • Trimming • Adjusting the lighting class based upon highway/area use or the tasks being undertaken – For highways this may be a reduction in lighting class – For areas around entertainment venues this may be an increase in lighting class when such venues close • Part-night lighting or Switch off. #ILPSummit
- 11. Looking at Adaptive Lighting Compensation for design maintenance factors is where the maintenance factor is simply designed out through the application of constant light output across the design maintained period “Trimming” is where currently the majority of public lighting switches on when ambient light levels fall to 70lux and switches off when the ambient level rises to 35lux. This was a standard approach that allows time for lamps to ‘warm up’ and reach their required operational output. #ILPSummit
- 12. Traffic Routes ADT Urban peak equivalent vehicles / hour Rural peak equivalent vehicles / hour 40,000 4,800 4,000 15,000 1,800 1,500 7,000 840 700 #ILPSummit
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- 14. So what to consider #ILPSummit
- 15. 15 Maximum Average Hourly Flow Average AADT BS5489 Traffic Flow ADT Correction Factor Traffic figure trigger point BS5489 Lighting Classification 262 2429 Very Low <7000 ME5 436 4502 Very Low <7000 ME5 1276 14875 Low to Moderate 7000 to 40000 ME3b Very Low 7000 0.471 601 ME4a 384 3802 Very Low <7000 ME5 1642 20705 Low to Moderate 7000 to 40000 ME4a Very Low 7000 0.338 555 ME5 1478 19652 Low to Moderate 7000 to 40000 ME4a Very Low 7000 0.356 527 ME5 4576 61793 High to Very High 40000 ME2 Low to Moderate 40000 0.647 2962 ME3b Very Low 7000 0.113 518 ME4a BS5489:2013 Table A2 Duel Carriageway High Density BS5489:2013 Table A3 Single Carriageway BS5489:2013 Table A3 Single Carriageway BS5489:2013 Table A3 Single Carriageway BS5489:2013 Table A2 Single Carriageway Essex: A414 EDINBURGH WAY E of A1019 Fifth Ave Essex: FIRST AVENUE HARLOW E of A1019 Fifth Ave Essex: A127 RAYLEIGH - EAST OF RAYLEIGH WEIR 113 114 115 116 117 118 49 No dimming possible as road is lit to the lowest possible level in accordance with BS 5489-1:2013 No dimming possible as road is lit to the lowest possible level in accordance with BS 5489-1:2013 ADT Classification Site Essex: RYE HILL ROAD HARLOW 358m SE of Longwood Essex: PARSLOE ROAD HARLOW Essex: WATER LANE HARLOW Essex: HARLOW ROAD ROYDON BS5489:2013 Table A3 Single Carriageway BS5489:2013 Table A3 Single Carriageway Lighting Class reduction when AADT reduces to Lighting Class reduction when AADT reduces to Lighting Class reduction when AADT reduces to Lighting Class reduction when AADT reduces to No dimming possible as road is lit to the lowest possible level in accordance with BS 5489-1:2013 #ILPSummit
- 16. 16 Site Date Day 00:00 01:00 02:00 03:00 04:00 05:00 06:00 07:00 08:00 09:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:00 21/03/11 Mon 7 1 0 1 5 36 98 235 333 172 111 125 121 145 131 173 239 314 179 86 58 36 24 20 15/03/11 Tue 8 6 1 1 10 24 114 243 384 185 130 150 151 145 157 181 260 359 166 100 48 50 29 22 16/03/11 Wed 8 4 1 2 12 33 94 228 338 169 124 119 145 149 152 212 232 336 189 98 63 32 29 15 17/03/11 Thu 9 2 6 0 10 34 115 239 347 184 139 130 154 165 187 183 262 350 182 91 64 43 37 21 18/03/11 Fri 14 6 5 0 10 41 94 228 309 181 143 143 143 160 169 211 242 290 170 83 47 34 29 17 19/03/11 Sat 17 10 7 3 1 13 27 59 83 119 158 157 161 135 119 127 103 109 84 60 47 43 34 30 20/03/11 Sun 27 15 6 5 5 8 24 24 33 76 93 100 122 108 95 85 90 78 66 54 46 27 20 11 21/03/11 Mon 9 8 3 5 12 68 232 505 560 317 207 230 251 268 257 343 403 509 363 183 123 75 58 25 15/03/11 Tue 9 10 1 3 22 90 244 519 560 252 186 211 217 198 274 303 421 549 380 219 113 94 69 36 16/03/11 Wed 11 7 3 4 20 84 226 536 553 266 197 223 234 272 266 340 418 544 346 196 135 107 52 48 17/03/11 Thu 17 6 3 2 18 72 239 534 539 285 223 201 227 225 251 334 466 535 384 216 113 92 80 50 18/03/11 Fri 20 16 3 9 16 73 232 441 498 301 249 236 250 267 292 329 404 475 323 213 127 85 66 58 19/03/11 Sat 30 17 10 4 13 30 64 92 157 209 258 308 339 316 267 246 273 262 205 183 98 87 79 59 20/03/11 Sun 47 26 11 12 6 19 35 41 88 148 170 212 289 279 255 223 188 176 168 110 100 68 43 16 21/03/11 Mon 50 21 39 44 114 277 748 1296 1355 917 782 831 875 857 982 1056 1318 1438 932 606 371 316 208 103 15/03/11 Tue 60 53 45 43 119 282 774 1321 1370 936 820 784 867 923 1000 1070 1335 1522 1050 599 420 325 238 119 16/03/11 Wed 62 55 36 46 116 304 779 1290 1347 971 782 817 891 950 1031 1152 1357 1522 1038 616 458 317 284 124 17/03/11 Thu 81 51 46 56 112 294 719 1323 1328 919 747 809 883 967 975 1064 1288 1509 1078 614 414 310 256 143 18/03/11 Fri 94 52 45 63 114 314 693 1273 1261 902 803 856 971 972 1047 1148 1349 1439 998 696 428 408 271 206 19/03/11 Sat 131 74 53 59 62 156 258 401 590 743 926 1075 1120 1159 1124 1039 1042 894 761 488 392 283 221 176 20/03/11 Sun 124 69 61 31 48 87 173 191 234 510 760 922 1162 1118 994 835 745 609 593 434 323 275 155 99 21/03/11 Mon 5 3 5 5 17 47 74 214 525 253 223 237 249 221 256 269 360 504 259 150 94 48 46 20 15/03/11 Tue 13 10 5 7 13 33 89 247 470 284 242 229 248 242 234 269 369 506 241 146 91 64 43 22 16/03/11 Wed 13 8 5 5 14 32 87 209 515 266 203 277 284 303 249 304 375 469 244 161 116 53 55 29 17/03/11 Thu 9 7 9 8 20 38 86 234 492 284 234 236 254 256 220 267 372 489 275 164 111 103 47 42 18/03/11 Fri 19 14 17 9 10 33 85 209 475 287 234 221 306 268 259 304 369 389 222 174 102 82 79 53 19/03/11 Sat 20 18 16 10 12 20 31 55 141 175 229 266 280 267 233 234 223 202 175 137 107 71 68 43 20/03/11 Sun 35 24 11 7 14 13 17 29 62 121 223 301 341 282 241 230 180 129 109 91 70 56 24 18 28/03/11 Mon 106 82 74 59 129 270 564 1230 1610 1330 1289 1458 1620 1638 1434 1513 1680 1755 1337 898 530 371 306 206 29/03/11 Tue 108 103 82 71 144 282 546 1339 1529 1424 1349 1396 1519 1564 1497 1487 1675 1705 1370 962 590 414 353 216 23/03/11 Wed 106 68 62 76 147 299 667 1341 1575 1405 1356 1431 1518 1475 1502 1465 1735 1753 1363 923 644 440 336 221 24/03/11 Thu 114 82 84 86 104 289 625 1335 1588 1379 1412 1465 1515 1564 1486 1471 1672 1790 1492 882 587 444 317 262 25/03/11 Fri 139 103 74 96 144 293 628 1255 1553 1383 1452 1468 1598 1689 1602 1605 1706 1716 1306 932 649 425 374 334 26/03/11 Sat 197 151 114 105 117 164 227 477 811 1207 1509 1770 1856 1770 1671 1650 1414 1248 1009 587 478 322 284 292 27/03/11 Sun 203 133 133 108 76 125 117 159 374 555 1043 1506 1782 1792 1681 1677 1239 813 637 508 431 305 239 180 21/03/11 Mon 70 42 31 31 57 177 473 1180 1675 1388 1183 1186 1253 1377 1393 1464 1590 1599 1314 914 653 491 314 144 15/03/11 Tue 64 30 23 24 63 202 439 1216 1792 1417 1207 1220 1272 1351 1321 1511 1609 1659 1413 1124 752 518 310 158 16/03/11 Wed 71 33 20 22 43 196 475 1198 1732 1332 1118 1216 1299 1370 1344 1468 1584 1635 1356 1052 733 549 401 175 17/03/11 Thu 80 30 25 27 45 193 470 1173 1717 1398 1153 1249 1395 1364 1431 1549 1628 1633 1439 1229 823 588 429 259 18/03/11 Fri 131 80 45 72 86 188 428 1153 1687 1529 1308 1409 1482 1513 1498 1622 1658 1677 1351 1119 815 653 472 321 19/03/11 Sat 240 127 117 88 73 89 224 416 700 1089 1384 1602 1733 1527 1488 1498 1383 1243 1029 880 678 536 409 361 20/03/11 Sun 236 149 138 110 85 65 132 216 257 616 1066 1242 1483 1410 1269 1185 896 738 731 614 462 417 256 140 16/05/11 Mon 347 194 160 204 403 1429 3202 5701 4960 3693 3338 3344 3340 3419 3641 4130 4856 5060 3896 2648 1814 1476 1053 573 23/05/11 Mon 351 214 169 164 420 1486 3310 5619 4993 3801 3385 3373 3358 3626 3645 3950 4603 5005 4292 2741 1717 1425 1011 642 17/05/11 Tue 355 213 185 214 406 1436 3301 5538 5100 3948 3450 3397 3361 3395 3701 4171 5077 5239 4216 2680 1911 1496 1215 657 24/05/11 Tue 320 189 173 198 436 1504 3337 5725 5243 3813 3382 3421 3453 3572 3572 4182 5119 5240 4178 2766 1937 1591 1197 675 18/05/11 Wed 343 211 176 216 431 1445 3286 5545 4958 4117 3405 3346 3445 3485 3770 4404 5015 5171 4102 2928 1951 1639 1361 703 25/05/11 Wed 392 220 157 209 465 1528 3353 5699 5197 3944 3604 3591 3485 3505 3657 3790 5027 5098 4234 2941 2066 1675 1396 747 19/05/11 Thu 362 226 184 213 412 1472 3364 5603 5098 3920 3527 3577 3325 3253 3821 4331 5002 4952 4099 3003 2047 1722 1369 1013 26/05/11 Thu 384 234 203 198 464 1463 3323 5681 5281 3923 3548 3385 3562 3627 3671 4224 4914 4904 4190 3152 2009 1675 1431 846 20/05/11 Fri 475 278 228 262 409 1447 3191 5526 4876 3802 3624 3590 3743 3869 4161 4605 5213 4892 4155 3084 2222 1657 1550 1158 27/05/11 Fri 445 257 242 267 417 1387 3130 5353 4978 3812 3635 3697 3912 3996 4208 4611 4997 4802 3992 3292 2229 1753 1669 1136 14/05/11 Sat 772 471 339 318 320 692 1228 1874 3080 3346 4174 4376 4448 4145 3625 3334 3472 3640 3366 2905 1836 1496 1601 1237 21/05/11 Sat 772 524 346 302 317 708 1204 2015 3005 3553 4016 4371 4184 4012 3787 3739 3665 3758 3561 3070 2123 1720 1646 1477 15/05/11 Sun 987 562 398 303 277 516 732 1053 1552 2610 3360 3696 4115 3878 3510 3156 3319 3176 2902 2290 1763 1413 986 743 22/05/11 Sun 1031 649 384 314 388 511 710 935 1418 2533 3480 3869 4163 3825 3412 3160 3236 3128 2977 2435 1956 1471 1247 677 Essex: A127 RAYLEIGH - EAST OF RAYLEIGH WEIR 113 114 115 116 117 118 49 Essex: RYE HILL ROAD HARLOW 358m SE of Longwood Essex: PARSLOE ROAD HARLOW Essex: WATER LANE HARLOW Essex: HARLOW ROAD ROYDON Essex: A414 EDINBURGH WAY E of A1019 Fifth Ave Essex: FIRST AVENUE HARLOW E of A1019 Fifth Ave #ILPSummit
- 17. Daily comparison follows across a week with trigger points – A127 Rayleigh – East of Rayleigh Weir 17 #ILPSummit
- 18. #ILPSummit Switching points – A127 Rayleigh – East of Rayleigh Weir 18
- 19. #ILPSummit The graph below shows the daily and 7 day average ADT for a 52 week sample of data on the A303 near to Stonehenge 19
- 20. #ILPSummit The following graph shows the daily and 7 day average ADT for a 1 week sample of data on First Avenue, Harlow. First Avenue is a two lane single carriageway with a 40mph speed limit. 20
- 21. #ILPSummit The graph below shows the daily and 7 day average ADT for a 2 week sample of data on First Avenue, Harlow. This is a two lane duel carriageway with a 50 mph speed limit. 21
- 22. #ILPSummit New Irish Guidance 0% 20% 40% 60% 80% 100% 120% 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:00 0:00 1:00 2:00 3:00 4:00 5:00 6:00 7:00 8:00 9:00 Profile 2 - Dimming LEDs 75% 67% 50% Midnight 6am
- 23. #ILPSummit What does it look like? M1 J21 to 21a showing the centre reservation dimmed from 100% down to 35% to show the maximum effect of dimming from 2cd/m2 to 0.7 cd/m2
- 24. #ILPSummit Not all Light Sources are the same 100.00% 20.00% 50.00% 10.00% 0.00% 20.00% 40.00% 60.00% 80.00% 100.00% 120.00% SOX SON CPO LED Full Max dim
- 25. #ILPSummit Summary For 95% of the roads assessed, the lighting can be reduced to the next class at 22.00 hrs. each day with the lighting being increased back to full output from 06.00 hrs. 25 The majority of roads reviewed have shown that only a reduction of one lighting class is applicable under BS 5489-1:2013 although in some instances a reduction of two lighting classes is achievable. This is essentially considered a ‘safe rule of thumb’ and suits the majority of cases looked at which statistically can be considered as a representative sample across the UK.
Editor's Notes
- Now, more than at any time in the recent past all Local Authorities are under pressure to reduce their energy bill and with many Local Authorities, Public lighting requirement representing at least a third of the their energy commitment and street lighting can be seen as an easy target. To support the Lighting Industry in the application of good practice regarding the employment of energy reduction strategies and technologies. A guidance to that will help Lighting Services to consider all of the implications that will be relevant when implementing various strategies. This can be a good thing providing an injection of capital to apply innovative invest to save project however LA’s can be applying various strategies some born from a requirement to reduce revenue cost rather than aligning to the requirements of Ultra Efficient Lighting ’providing the right light, in the right place at the right time and controlled by the right system’.
- BS5489-1, 2013 advises us of a 5 step strategy to help us understand Step 1 – the tables within BS5489-1 make general assumptions about the environment and activities within which the road lies. Step 2 – requires the area to be actually reviewed to determine the nature of the area and how the road is used Step 3 – requires you to consider the finds of step 2 and through a risk assessment / appraisal adjust the lighting class in stage 1 to suit actual conditions Step 4 – only applies to subsidiary roads, adjusting the level to suit the S/P ratio Step 5 – this relates to this report and requires the designer to consider if the task changes during the night and thus can adaptive lighting be used, as such adaptive lighting is applicable to all forms of exterior lighting under Bs5489-1:2013. It should be noted that at all times a defined lighting class must be achieved, this is stated within the Standard.
- So we need to understand the lighting classes that are applicable to your design and the difference in classes and then ensure that you have the technologies to enable movement between them. Stepped ballast, CMS controlled ballast/driver etc. While this step is straight forward and your choice of equipment will largely depend on what you wish to achieve for your network within in whatever budget constraints you have, the major problem has been understanding who you can identify when you can adapt the lighting.
- Adaptive lighting whereby lighting classes are set appropriately to meet the requirement for the conditions at a particular time of the night and thereby are applied according to street activity rather than remaining at a pre-determined level. This should reduce the energy bill yet still provide the required levels of illumination on the street, area or car park. Varying lighting levels are based upon highway and / or area use by all users and include considerations for the following. For highways this may be a reduction in one or more lighting classes. For areas around entertainment venues this may be an increase in lighting class when for example such venues close. And by now we are all aware of the benefits of light sources with Ra’s > 60 more info is available within TR29 and PLG03 (available at all good lighting institutions) There is much evidence that shows that white light (defined as having a colour rendering index of Ra 60 or higher) improves perception and that if it is used then lighting levels could be reduced without perceptible impact on a person’s vision. The research is summarised in the ILP Reports TR29 White Light and PLG 03 Lighting for Subsidiary Roads: Lighting design has always been undertaken to address the worse case however the conditions of the worse case say 6 o'clock on a Decembers evening (rush hour) may only last for a couple of hours which effectively means that we could be over lighting the highway for 80+% of the time. In fact for most of the year the conditions that require the traditional design lighting level may not even exist within the hours of darkness. So applying the principles of UEL, if we can understand what the lighting class is at any time then the correct lighting solutions can be applied. OK that great, but how do we know what the lighting class is at any give time? Well the British and European Standards allow illumination levels to be varied depending upon the category of road and its usage. Therefore illumination levels could be reduced when traffic flows are lower, for example between midnight and 5am and still provide the right lighting for all road users. Lighting could also be increased as a crime reduction measure, say outside night clubs for a defined period after they close. So maybe time to look at lighting design in a slightly different way. BS 5489-1:2013, allows lighting during different periods of night to be classified differently. Type of road Traffic flow, either by flow rate or as a percentage of carriageway design capacity Presence of conflict areas Presence of traffic calming features (in general horizontal deflection) Crime risk Ambient luminance levels Social and economic considerations Security considerations
- Adaptive Lighting is the term we are using to describe any change to a lighting solution whereby a lighting solution changes in it basic operational status throughout its operational period, this may be through Compensation for design maintenance factors Trimming Adjusting the lighting class based upon highway/area use or the tasks being undertaken For highways this may be a reduction in lighting class For areas around entertainment venues this may be an increase in lighting class when such venues close Part-night lighting Switch off. We now have access to the control equipment to cover all adaptive lighting scenarios from Switch off through to full dynamic adaptation. We now have the technologies readily available to deliver almost any adaptive lighting strategy that may be appropriate. From simple “Switch off” through to fully interactive dynamic solutions adapting to the environmental requirements at any given time.
- Compensation for design maintenance factors we can look to ‘reverse engineer’ the project Maintenance Factor over the period of the lamp installation life (say, four years) effectively reducing the lamp by 25% at the outset of the installation and then over the lamp ( light source) installation life adjust lamp output to compensate for the reduction in light output and luminaire dirt build up. This will ensure that the correct lighting level is provided on the highway / public area and reduce the electrical load of the installation and allowing for performance tolerances by around 20%. Trimming came around due to the need to save energy but also due to the awareness that modern lamp sources and control gear take less time to warm up to full output once switched on than older sources with magnetic control gear. Consideration was also given to “why do we turn all lights on at 70lux when for example the street is only required to be lit to 10 lux?” Essentially the lighting is up to full output before the ambient lighting levels have fallen to the level required by the artificial lighting installation. Next Slide
- Table A.2 of BS 5489-1:2013 and shows how the lighting class can be varied depending upon traffic flow Where adaptive lighting is applied on main and principal routes it may be necessary to give due consideration to be able to override the switch off in the cases of: Accidents Road works (lane restrictions, diversions) Events. The footnote associated with Table 2, Traffic flows within BS 5489-2:2003 +A1:2008 Code of practice for the design of road lighting —Part 2: Lighting of tunnels enables the designer to undertake an assessment of peak hourly flow against daily traffic flow as follows. The note states: If the actual value is not known, peak hour traffic can be derived as follows. Average daily traffic (ADT, vehicles per day) is the most used concept in traffic planning and it is always known. Peak hour traffic (vehicles per hour) is in rural areas 10 % and in urban areas 12 % of ADT. On undivided roads, the number of vehicles per hour per lane can be calculated by dividing peak hour value by the total number of lanes.
- The challenge facing the production of this guidance was to provide “simple clear guidance” , a year ago we appealed for traffic flow data and we did collect and collated a fair amount of this info The panel look at the data and applied it to a “time and traffic flow” graph and these roads as do most we looked at have a similar profile which we considered could become a generic time profile for adaptation. However this is not straight forward The PLG08 panel has considered if a generic profiling assumption based upon sample data for a large range of roads for traffic use may be attainable and relevant It should also be noted, as can be seen from the following charts, that the daily flows within a section of highway will also vary depending upon its place within the road hierarchy and the day of the week. Monday evening to Friday morning traffic flows are in general very similar as weekday commuters travel to their place of work. On principal routes, higher traffic flows exist for longer on Friday and Sunday nights and to a lesser degree on Monday morning, due to long distance commuters as shown on the graph for the A303 below. The traffic flow on local routes between Monday and Thursday are comparable with subtle variations on a Friday and Saturday night due to nightlife activities. The weekend flows are generally different, with lower flows in the morning and evening and a peak flow during the middle of the day. This permits a clearer view of the traffic flow and a more accurate assessment of when the variation in lighting classes can be applied. The same principles for the trigger points are used as before and follow the same application of the lighting classes. The 7 day average ADT has been included to show the effect of combining the ADT for all 7 days has on the distribution. The traffic data provided for these sites are between whole hours, e.g. 01:00 till 02:00 therefore the data has been shown at the half hourly point. The yellow portion of the chart indicates mid-winter and the light blue mid-summer.
- We are trying to ensure that we explain data like this where annual cycles are understood and the correct lighting classes applied for the task The top graph indicates the peak flow rate is in the daylight hours trigger points for class variation is 7am and 8.30pm & The second graph traffic flow only reaches the intervention between 5 & 7pm These are only snap shots of two particular sections of highway however we have hopes that the theory behind this can be employed to deliver a simplified approach.
- Using the traffic data in a tabular form and applying conditional formatting it is possible to identify which lighting class may be applicable for each hour throughout the 24 hour period. However the information is of course primarily used to identify when the trigger point is reached. The results show that generally for each road on a Monday to Friday the changes in lighting class can be applied at the same time. However, the times are different over the weekend with both Saturday and Sunday changing lighting classes at different times. What can be seen from the tabular method of showing the times that lighting levels can be varied is that only hourly assessments can be made. Where there are subtle variations a better assessment can be made using graphs. A point worth clarifying is that the correction figure is applied to the daily traffic flow figures which are used to work out the ADT. This is shown in the following graphs. The arrow points towards the peak corrected average ADT equivalent for 7,000 or 40,000 ADT respectively.
- The graph for the A127 at Rayleigh shows that the lighting class may be varied by two classes. The first reduction in lighting occurs when the last traffic flow on a Friday crosses the trigger point at 19:30. The second reduction in lighting class occurs when the last traffic flow crosses the trigger point on a Sunday morning at 02:00. In reverse, the first earliest switching point where the lighting class should increase occurs when the first traffic flow crosses the trigger point on a Monday to Friday morning at 04:30. The second earliest switching point where the lighting class should increase occurs when the traffic flow crosses the trigger point on a Monday to Friday morning at 06:15. During the long summer days the traffic flow is such that the full lighting class is not required during those months, also during the longest days the lighting is extinguished before it returns to its first reduction in lighting class. During the winter months the flow is such that the full lighting class is required
- The application of adaptive public lighting and the application of a responsible energy management strategy according to road usage is clearly an energy saving approach that requires due consideration. The Standards permit the lighting levels within the public areas and highways to be changed depending upon use and the task to be lit. Therefore a system that ensures the right lighting levels are applied at the right times will bring about maximum energy savings whilst still providing the required level of service to the public without compromising safety. The following approach taken from Annex A of BS 5489-1:2013 should be followed when considering the application of lighting to any public area: Step 1 Select the benchmark lighting class from the relevant BS 5489 table Step 2 Carry out a risk assessment to identify specific lighting needs for the road Step 3 If necessary, adjust the lighting class up or down based on the assessed risks Step 4 Adjust the lighting level according to the light source being used (S/P ratio) when the light source has an Ra > 60 and is a subsidiary road only Step 5 Assess the lighting requirements to judge whether different lighting classes are applicable at different times of the night due to changes in traffic or pedestrian use In summary, the application of adaptive lighting should consider: BS5489-1:2013 & BS EN 13201:2003 permit variable lighting levels by permitting a road or area to be classified depending upon the use of that road or area at any given time Positive cost benefit required Reduction in energy Lighting for safety must be considered and it is imperative that the safety of the user is not unduly compromised If there is any doubt, then full lighting should be maintained at all times The risk of crime is unlikely to change as traffic flows change Considerations for increasing lighting levels are defined times based upon crime risk e.g. outside nightclubs, pubs etc. The panel has found through the analysis of the information previously described that for 95% of the roads assessed, the assigned main lighting Class can be reduced to the next class at 22.00 hrs. each day with the Class being increased back to full output from 06.00 hrs. The majority of roads reviewed have shown that only a reduction of one lighting class is applicable under BS 5489-1:2013 although in some instances a reduction of two lighting classes is achievable. This is essentially considered a ‘safe rule of thumb’ and suits the majority of cases looked at which statistically can be considered as a representative sample across the UK.