Rear lights: which is best, continuous or flashing?

Sep 13, 2020
82
40
I've always opted for the continuous light, but went out for a swift 5 mile spin tonight to get a bit of fresh air, and noticed three other cyclists all sporting flashing rear lights.

I suppose you could argue that the flashing light draws the motorist's attention more easily. But at the same time might be a distraction?

Don't know.

Thoughts?
 

AndyBike

Esteemed Pedelecer
Nov 8, 2020
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174
Steady liughts can blend into the background lighting,maybe confused by appearing to be a reflector of a car in front.or projected lights from shops etc. flashing at least is attention grabbing. no other vehicle on the road utilizes a flashing red light.
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
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I run steady at night but if merky flashing, during busy times flashing .
 

guerney

Esteemed Pedelecer
Sep 7, 2021
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I use a red blinky, plus a steady rear light, plus I wear a flashing red LED shash on my shoulder... and drivers still sometimes do not see me at all. Maybe they're texting, or something very important like that. Or maybe their cars are on cyclist-blind autopilot.

 
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Nealh

Esteemed Pedelecer
Aug 7, 2014
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Things likely won't be much different after the 29th when the new hierarchy rules of the HWC come in to force if agreed on and passed.
 

matthewslack

Esteemed Pedelecer
Nov 26, 2021
531
259
I've always opted for the continuous light, but went out for a swift 5 mile spin tonight to get a bit of fresh air, and noticed three other cyclists all sporting flashing rear lights.

I suppose you could argue that the flashing light draws the motorist's attention more easily. But at the same time might be a distraction?
Retroreflective patches on my panniers ends, and strips all over my high vis jacket, and two lamps, one flashing one steady, and unless it's raining, slightly fluorescent lime green leggings...no excuse for not seeing me!
 

DiggyGun

Pedelecer
Mar 21, 2021
116
52
This is some guidance I’ve found on the new Highway Code in relation to bike lights.;

“Want to know the law when it comes to cycling in the dark? Simon Bever, our friendly expert, explains all you need to know about staying legal and well lit when cycling on public roads.
It is illegal to cycle on a public road after dark without lights and reflectors. Exactly which lights and reflectors, where to fit them and when to light up, is defined by the Road Vehicles Lighting Regulations (RVLR).
When you ride a bicycle in the dark, the law requires you have lights and reflectors; and the law is quite detailed as to what lights and what reflectors you use.
The RVLR, which were first published in 1989, and then amended in 1994, 1996, 2001, 2005, again in 2005 and most recently in 2009. While most of the amendments made no difference to cyclists, it is still quite a task to work out what the law is.
It is true to say that few police officers will know the finer details of these regulations, and so long as you are showing a white light at the front and a red light at the rear then you are unlikely to be challenged. However, if you're involved in an accident at night, any slight irregularity could be challenged in court and may be regarded as 'contributory negligence' (a polite way of saying that the accident is partly your fault!)
The main points of RVLR are as follows:
  • Lights and reflectors are required on a pedal cycle only between sunset and sunrise.
  • Lights and reflectors are not required when the cycle is stationary or being pushed along the roadside.
  • When they are required, the lights and reflectors listed below must be clean and working properly.
Note: Reflectors have to be fixed to the rear of your bike and to the front and rear of each pedal. The Pedal Cycles (Safety) Regulations (PCSR) ensure that every new bicycle is sold with several extra reflectors, some of which are not required by RVLR (you may have seen bikes with yellow or white reflectors placed in the spokes).
However, you only have to look around to see that most reflectors are subsequently removed from the bike and, in the case of 'racing' bikes, the pedals are frequently changed for cleated versions that rarely have even have space for reflectors to be fitted.
Below is little more explanation of the 'details' of the regulations so that you can be sure to equipped with at least the minimum requirements.
Front lamp
  • At least one lamp is required, showing a white light, positioned centrally or offside (the right-hand side of the bike), up to 1500mm from the ground, aligned towards and visible from the front. If capable of emitting a steady light, it must be marked as conforming to BS6102/3 or an equivalent EC standard.
  • If capable of emitting only a flashing light, it must emit at least 4 candelas.
Note: It might sound obvious, but the light needs to be fixed to the bicycle; there is a fashion for helmet lights which can be pointed in the direction you're looking which might be useful but is not legal. A single helmet mounted light doesn't conform - and if you're an adult, then the chances are that your helmet light will be more than the 1500mm height limit from the ground anyway.
The reference to '4 candelas' isn't very useful because most bike lights are given an output in 'lumens'; for a guide, 1 candela approximates to 12 lumens, so the tiny blinky flashing lights which usually put out around 25 lumens won't enough on their own; you'll need at least two of them.
Rear lamp
  • One is required, to show a red light, positioned centrally or offside (the right-hand side of the bike), between 350mm and 1500mm from the ground, at or near the rear, aligned towards and visible from behind. If capable of emitting a steady light it must be marked as conforming to BS3648, or BS6102/3, or an equivalent EC standard. If capable of emitting only a flashing light, it must emit at least 4 candelas.
You might have noticed that rear bike lights tend to have much lower lumen outputs than front lights. Firstly, is because we're unlikely to want to see where we're going with the rear light but it is also because our eyes react differently to red and white lights; to our eyes, a 50 lumen rear light has similar brightness as a 200 lumen front light
Flashing lights
It took until 2005 for the Regulations to be amended to allow the use of flashing bicycle lights (the older type of battery lights in existence when the Regulations were originally drawn up weren't able to flash). The 2005 RVLR amendment meant that it was now legal to have a flashing light on a pedal cycle, provided it flashed between 60 and 240 times per minute (1 – 4Hz).
The amendment also meant that a flashing light was approved, meaning no other light was needed in that position. And since BS6102/3 does not cater for flashing, approval is granted simply on the basis of its brightness (as specified above).”

As you will see, it really clarifies what’s required, not.

Rear LED lights are not that expensive, so for me and my own personal choice and for safety’s sake, I use two rear Red lights. One with a steady light and one with a double flash.
 

nigelbb

Pedelecer
Sep 19, 2019
244
209
I've always opted for the continuous light, but went out for a swift 5 mile spin tonight to get a bit of fresh air, and noticed three other cyclists all sporting flashing rear lights.

I suppose you could argue that the flashing light draws the motorist's attention more easily. But at the same time might be a distraction?

Don't know.

Thoughts?
I never cycle at night. It's too bloody dangerous. As a motorist flashing lights draw my attention as they are so bloody irritating but I don't think they are as effective as decent output continuous lights especially for headlights. I'm sure that you can you see badgers in the road better with a normal headlight than with a disco strobe light.
 

DiggyGun

Pedelecer
Mar 21, 2021
116
52
I never cycle at night. It's too bloody dangerous. As a motorist flashing lights draw my attention as they are so bloody irritating but I don't think they are as effective as decent output continuous lights especially for headlights. I'm sure that you can you see badgers in the road better with a normal headlight than with a disco strobe light.
You’re talking about lights that have different functions.

With front lights there are two types;
- Lights to see with; bright and cover a good distance
- Lights to be seen; flashing or steady
 
Oct 20, 2021
203
65
I never cycle at night. It's too bloody dangerous. As a motorist flashing lights draw my attention as they are so bloody irritating but I don't think they are as effective as decent output continuous lights especially for headlights. I'm sure that you can you see badgers in the road better with a normal headlight than with a disco strobe light.
I didn't have any time to see the badger, despite the way the video looks, I was going slow (wide-ange action camera lens). There was no time, it jumped out of a hole in a hedge which was right up against the road. I couldn't have avoided it. A brighter headlamp wouldn't have helped - no time. CYCLISTS! BEWARE OF BADGERS! :eek:

 

DiggyGun

Pedelecer
Mar 21, 2021
116
52
I didn't have any time to see the badger, despite the way the video looks, I was going slow (wide-ange action camera lens). There was no time, it jumped out of a hole in a hedge which was right up against the road. I couldn't have avoided it. A brighter headlamp wouldn't have helped - no time. CYCLISTS! BEWARE OF BADGERS! :eek:

Hopefully you were OK and the bike not to damaged.

I had a similar experience in my car a few years ago at 0400 in the morning after coming back from Hospital. A Muntjac deer jumped into the front of the car from the hedgerow. No time to brake and it went underneath the car and caused nearly £5000 worth of damage.
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
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West Sx RH
Hopefully you were OK and the bike not to damaged.
You haven't been following the furry badger thread then!!!!
Injuries sustained were quite serious and a longish road yet to recovery.
 
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Sep 13, 2020
82
40
This is some guidance I’ve found on the new Highway Code in relation to bike lights.;

“Want to know the law when it comes to cycling in the dark? Simon Bever, our friendly expert, explains all you need to know about staying legal and well lit when cycling on public roads.
It is illegal to cycle on a public road after dark without lights and reflectors. Exactly which lights and reflectors, where to fit them and when to light up, is defined by the Road Vehicles Lighting Regulations (RVLR).
When you ride a bicycle in the dark, the law requires you have lights and reflectors; and the law is quite detailed as to what lights and what reflectors you use.
The RVLR, which were first published in 1989, and then amended in 1994, 1996, 2001, 2005, again in 2005 and most recently in 2009. While most of the amendments made no difference to cyclists, it is still quite a task to work out what the law is.
It is true to say that few police officers will know the finer details of these regulations, and so long as you are showing a white light at the front and a red light at the rear then you are unlikely to be challenged. However, if you're involved in an accident at night, any slight irregularity could be challenged in court and may be regarded as 'contributory negligence' (a polite way of saying that the accident is partly your fault!)
The main points of RVLR are as follows:
  • Lights and reflectors are required on a pedal cycle only between sunset and sunrise.
  • Lights and reflectors are not required when the cycle is stationary or being pushed along the roadside.
  • When they are required, the lights and reflectors listed below must be clean and working properly.
Note: Reflectors have to be fixed to the rear of your bike and to the front and rear of each pedal. The Pedal Cycles (Safety) Regulations (PCSR) ensure that every new bicycle is sold with several extra reflectors, some of which are not required by RVLR (you may have seen bikes with yellow or white reflectors placed in the spokes).
However, you only have to look around to see that most reflectors are subsequently removed from the bike and, in the case of 'racing' bikes, the pedals are frequently changed for cleated versions that rarely have even have space for reflectors to be fitted.
Below is little more explanation of the 'details' of the regulations so that you can be sure to equipped with at least the minimum requirements.
Front lamp
  • At least one lamp is required, showing a white light, positioned centrally or offside (the right-hand side of the bike), up to 1500mm from the ground, aligned towards and visible from the front. If capable of emitting a steady light, it must be marked as conforming to BS6102/3 or an equivalent EC standard.
  • If capable of emitting only a flashing light, it must emit at least 4 candelas.
Note: It might sound obvious, but the light needs to be fixed to the bicycle; there is a fashion for helmet lights which can be pointed in the direction you're looking which might be useful but is not legal. A single helmet mounted light doesn't conform - and if you're an adult, then the chances are that your helmet light will be more than the 1500mm height limit from the ground anyway.
The reference to '4 candelas' isn't very useful because most bike lights are given an output in 'lumens'; for a guide, 1 candela approximates to 12 lumens, so the tiny blinky flashing lights which usually put out around 25 lumens won't enough on their own; you'll need at least two of them.
Rear lamp
  • One is required, to show a red light, positioned centrally or offside (the right-hand side of the bike), between 350mm and 1500mm from the ground, at or near the rear, aligned towards and visible from behind. If capable of emitting a steady light it must be marked as conforming to BS3648, or BS6102/3, or an equivalent EC standard. If capable of emitting only a flashing light, it must emit at least 4 candelas.
You might have noticed that rear bike lights tend to have much lower lumen outputs than front lights. Firstly, is because we're unlikely to want to see where we're going with the rear light but it is also because our eyes react differently to red and white lights; to our eyes, a 50 lumen rear light has similar brightness as a 200 lumen front light
Flashing lights
It took until 2005 for the Regulations to be amended to allow the use of flashing bicycle lights (the older type of battery lights in existence when the Regulations were originally drawn up weren't able to flash). The 2005 RVLR amendment meant that it was now legal to have a flashing light on a pedal cycle, provided it flashed between 60 and 240 times per minute (1 – 4Hz).
The amendment also meant that a flashing light was approved, meaning no other light was needed in that position. And since BS6102/3 does not cater for flashing, approval is granted simply on the basis of its brightness (as specified above).”

As you will see, it really clarifies what’s required, not.

Rear LED lights are not that expensive, so for me and my own personal choice and for safety’s sake, I use two rear Red lights. One with a steady light and one with a double flash.
Thanks for that really useful info. Never knew.
 
Sep 13, 2020
82
40
I never cycle at night. It's too bloody dangerous. As a motorist flashing lights draw my attention as they are so bloody irritating but I don't think they are as effective as decent output continuous lights especially for headlights. I'm sure that you can you see badgers in the road better with a normal headlight than with a disco strobe light.
You're right it's several orders of magnitude more dangerous than cycling in daylight. If I go out at night I only cycle along well lit roads. Tried an unlit lane a couple of months ago, and had to cycle slowly anyway as I didn't know the lane very well, and was concerned I might hit an obstacle or pothole. But the worst thing was the occasional oncoming car. Had to stop as the headlights were blinding and disorientating. I won't be trying that again in a hurry.
 
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Nealh

Esteemed Pedelecer
Aug 7, 2014
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