That was not an inherent requirement of LED technology.
It was a choice.
And the choice of colour temperature became increasingly important as councils gained experience with large-scale LED replacements.
The biggest practical advantage: energy
The strongest argument for replacing old street lights with LEDs is energy efficiency.
Local authorities across Britain have reported substantial reductions after LED conversions.
Suffolk County Council, for example, says its LED programme was expected to reduce electrical energy costs by at least 60 percent. The council also states that the LED units installed have an expected operating life of around 25 years, compared with up to six years for the traditional lamps they replaced.
North Yorkshire Council similarly reports that replacing around 50,000 street lights with LEDs has reduced street-lighting energy consumption by about half, while saving around 10 million kWh annually and approximately £3.5 million per year in energy costs based on its stated energy rates.
These figures help explain why councils have been willing to invest in large-scale replacement programmes.
Street lighting represents a significant long-term operating cost.
If thousands of lights can use substantially less electricity while providing adequate illumination, the financial argument becomes difficult to ignore.
And the savings are not limited to electricity.
LED systems can also reduce maintenance requirements because their expected service life is generally much longer than that of older lamps.
That matters when a local authority is responsible for tens of thousands of street lights.
Replacing one failed lamp might be simple.
Replacing thousands of them over many years is not.
LEDs also changed what a street light can do
The difference between sodium and LED lighting is not simply the colour of the bulb.
Modern LED systems can be much more controllable.
The light can be directed more precisely toward roads and pavements rather than being scattered in unwanted directions.
LED systems can also be integrated with central management systems, allowing authorities to monitor, control and sometimes dim individual lights.
Suffolk County Council notes that its LED system can be dimmed alongside a central management system as road use decreases, creating additional opportunities to reduce energy consumption.
That kind of control is difficult to achieve with many older lighting systems.
Instead of treating every street light as an independent device that simply switches on and off, modern infrastructure can make lighting more responsive.
A road can potentially receive different lighting levels at different times of night depending on its location, use and environmental requirements.
This is one reason why comparing a sodium lamp with an LED lamp as if they were simply two different light bulbs misses part of the story.
An LED street-lighting system can be an entire management platform.
But why do LEDs sometimes feel worse?
This is where the debate becomes more interesting.
If LEDs are more efficient, longer-lasting and more controllable, why do some people still prefer the old sodium glow?
Part of the answer is colour temperature.
Colour temperature is measured in Kelvin, or K.
A lower colour temperature generally produces a warmer, more yellow or amber appearance.
A higher colour temperature produces a cooler, whiter or bluer appearance.
Some early large-scale LED conversions used relatively cool white light, often around 4000K.
That could produce a very different nighttime environment from the warmer light people were accustomed to.
The difference can be immediately noticeable.
A familiar residential street that once appeared soft and amber may suddenly look bright, white and sharply defined.
The pavement can appear more prominent.
Building surfaces can look harder.
Shadows may appear different.
And the entire street can feel more exposed.
Whether that is better or worse aesthetically is subjective.
But the change itself is real.
The psychology of familiar light
There is also another factor that cannot easily be measured on an energy bill.
Memory.