The logic of asking a question via BiB’s anonymous Contact form escapes me but here is today’s.
If, as your lighting engineer says, the efficiency of LED lighting is less, why has the council installed the things? One of the roads near where I live has had the already dimmed down sodium lighting for ages. So why change that?
The ‘best’ Sodium lights produce 177 lumens for every watt of electricity consumed. The newer and less orange Sodium lamps are dimmer and produce around 100 lumens per watt. The very best of the LEDs are not very different; so where’s the saving?
What Bexley Council has done is fit much less powerful lights, only 69 watts (in main roads) instead of 180 watts so there is a big saving on electricity but at the expense of your safety.
Even if the lamps are equally efficient in converting watts to lumens, 69 watts (LED) is a great deal smaller than 180 watts (Sodium). As The Council Officer almost said, you can’t defy the laws of physics.
In theory they could have fitted much smaller Sodium lamps but the Council is gambling on LEDs having a lower failure rate. If they are wrong they have not only put your safety at risk but they will have wasted your money too.