New York City testing various hybrid truck technologies, winner will emerge huge.

I agree with most of your comments. Especially the first generation LED lightheads, were pretty bad. IMHO the best strobes, say from Whelen, are still the best for long range

The newest properly designed LED lightbars, such as those from Whelen and Axixtech, are almost as bright as strobes, and depending on the angle, brighter. The key is proper design, the badly designed LED lightheads are barely visible in daylight

The unmarked Critical Infrastructure emergency vehicles I have drove, also have hidden strobes in the high beam housing of the vehicle. These can ONLY be used in daytime, for obvious reasons

 

They need to incorporate thermostatically controlled heat sources in the light housings; maybe heat tape like one uses to keep pipes from freezing. That would solve the problem, but only waste energy when the weather is cold enough to obsure the lights, not all year round.

 

Yes, good point raised about snow/ice buildup on LED traffic lights.

It's ironic that they were promoted for labor savings by lasting longer, but you still have to send crews out to clean the snow/ice off

You wouldn't need much of a heater to keep the lens clear, but typically most streetlights are low voltage. The wiring bundle inside the arms wouldn't handle the extra current required to run an electric defroster, so additional wiring would be needed

 

If the wiring was able to keep the bulbs hot enough to melt the snow, it would be no different than putting in a heater (aka resistor).

After all - an incandescent bulb is just an electric heater that also happens to generate light.

So no wiring upgrade would be necessary unless they downsized the wiring in the arms specifically for the LED bulbs with no plans of ever using conventional bulbs.

 

They never have to do that where I live.

They converted all of the traffic lights in Sacramento County several years ago. I think some of the smaller rural towns in Northern Calif may still have some, but I don't remember the last time I saw a traffic light that wasn't the LED type.

 

The traffic lights work differently now, due to additional sensors for things like Transit Priority signals, emergency vehicle priority switching, etc

With the LED's, most of the control information is now multiplexed. The traffic control is entirely solid state, no more relays.

The result of all that, adding a resistance element to keep the lens warm would disrupt the control signals

 

This is why our outside Christmas lights are plain old C7 incandescent bulbs. LEDs would disappear under the snow.

Tom

 

I'm surprised you haven't disappeared under the snow/ice already, due to storms