Ultrabright warning lights – never a brilliant idea for safety!

Last week I received an email from David Green urging me to read a new post from the Police Inspector Blog. The posts are written by the popular and accomplished book author  who writes in the UK under the Inspector Gadget nom-de-plume.  The blog is headlined ‘When practitioners are not consulted’ and goes on to discuss what happens when the people in charge of procuring the new national standard police vehicles forget to talk to their patrol officers about the equipment selected? Follow-up articles have been published in the Mail Online and the Telegraph newspapers.

Police Accident scene

Police accident scene

It comes as no surprise that issues surrounding vehicle and equipment procurement programs result in ongoing problems for the thousands of  response agencies scattered across the globe.  The Gadget blog discussion lists five vehicle equipment issues that have caused problems locally for the Inspector and his colleagues. A reprint outlining the issue of overly bright warning lights in point five is as follows :

“The new red and blue strobes on the roof of the vehicles are so bright that they disorient drivers on the motorway who are trying to pass an accident scene at night, and create a second accident right on top of the original one. A fire fighter jumps out of a fire appliance and runs over to the police crew shouting ‘get those bloody lights off, we can’t see anything ahead’. Nice, when the trucks are bearing down on you at 60 mph”.

Here is a real life example of overbright warning lights causing problems, not just for the civilian drivers passing nearby but also the co-responding emergency services personnel as well. Wake and Moth Effect accidents are a direct result of ultrabright warning lights disorienting and confusing other drivers as they approach the emergency vehicle. Industry suppliers often ignore calls for the moderation of lamp output, stating that ‘brighter is better’ and that high levels of light intensity are needed, especially under bright sunlight conditions. Many light-heads cannot be programmed to reduce the same output at night, thus producing excess glare that directly results in the loss of night vision of nearby drivers.

I have spoken at length at conferences and seminars over the years about the dangers of overbright warning lights and the issues affecting nearby drivers:

Wake effect accidents occur in low light or at night when an emergency vehicle is responding through traffic. The glare of the overbright warning lights affects the night vision of other drivers. After the emergency vehicle has passed-on the affected driver loses his night-vision and while disoriented and confused, then crashes into another vehicle or nearby roadside object. The crashes may also happen when driving a vehicle past or through an accident scene with bright and dazzling light displays.

Moth Effect collisions are caused by motorists who shift their attention to the warning lights while driving past and subsequently crash into the emergency vehicle or the personnel working nearby. Individual drivers who are fatigued , alcohol or drug affected are more likely to be involved in this type of accident. Solomon proposed that switching down to a simplified arrangement of amber lighting would reduce the likelihood of Moth Effect accidents.

The Blue advancing – Red receding illusion becomes even more pronounced with brighter lighting at night. Testing demonstrated that when an emergency vehicle was stationary on the roadway with blue warning lights illuminated, between 26% and 31% of participants believed the vehicle was in fact approaching them. When red lighting was illuminated, more than 50% of the participants believed the emergency vehicle was moving away, thus increasing the chance of a rear end collision.

The new trend for bright warning lamps to be placed on wing mirrors or around the emergency vehicle at the passing driver’s eye level should be discouraged and the offending lamps removed. Driver’s stopped alongside or being passed by an emergency vehicle may experience temporary blindness or after-images if they glance sideways only to find themselves less than a meter away from a brilliant and dazzling flashing light-head. This glare and dazzle can occur even in daylight hours. The lamp manufacturers also warn in their literature that viewing high-intensity LED lamps at close range may cause temporary blindness or permanent eye damage.

Drivers or observers in the older age groups (over 40 years) may be affected to a greater extent by high intensity lighting due to aging changes and optical deterioration within their eyes. Excessive glare and slower recovery times from glare  means these drivers are at an increased risk of accidents.

Emergency personnel working around vehicles fitted with ultra-bright lighting may experience excessive glare levels that interfere with their ability to work at the incident scene. The distraction and visual irritation caused by intrusive flash patterns may increase as they work around or walk past brightly flashing roof lightbars mounted on sedans at or near the responder’s standing eye-level.

As you have read, warning lights that are too bright actually reduce the level of safety rather than enhance it. The Ambulance Visibility website has more information about warning lights and the Latest News at AV has links to an article and YouTube video demonstrating warning lights that are too bright fitted to Washburn County 1V32 ambulances.


About John Killeen (Ambulance Visibility)

John Killeen is a former Intensive Care Paramedic who authors the Ambulance Visibility research website & blog
This entry was posted in Ambulance, Emergency vehicles, EMS, Fire, High Visibility, Police, Rescue, SES, Significant & Important Blogs, Warning Lights and tagged , , , , , , , , , , , , , , . Bookmark the permalink.

5 Responses to Ultrabright warning lights – never a brilliant idea for safety!

  1. Davyd says:

    I wonder if ‘bright flashing’ is always the best way to identify an emergency vehicle, or incident. Perhaps steady lights would work in some cases. In a previous post you mentioned the problem of police motorcycle visibility; I wonder if steady white lights pointing to the sides would help. The rationale would be they would look like an on-coming vehicle and drivers usually react strongly to the threat of an oncoming vehicle with heightened attention. Needs research, of course to test it. Similar on motorways/highways. Perhaps the plethora of flashing lights makes it harder for drivers to assess what is happening and where (spatially). A set of steady lights facing the traffic might be better,rather than every attending EV displaying its own set of flashing lights: all different colours, rates of flash and asynchronisation would make it very difficult for (a) drivers to concentrate, and (b) to determine distance. That said, I’m not sure how this would deal with ‘seen by not noticed’ accidents.


  2. inspectorgadget says:

    Thanks for bringing this to Australia. Thanks also for the additional information. I will re-post this at some stage.
    Best Wishes to you.


    • Thanks for your comments:- In brief, flashing warning lights remain the optimal solution during the emergent response phase. A number of researchers, including Stephen Solomon recommend that emergency vehicles switch down to amber once on-scene. ACT Ambulance vehicles in Canberra respond with red & blue flashing lights along with a ring of amber steady-burn lamps around the vehicle. Once on-scene the flashing lights are switched off, leaving the steady amber illuminated. The ACT crews frequently use ambers in fog, outside homes at the kerbside, parked on the median strips of main roads or in crowds at large events.

      When a large number of emergency vehicles are parked at night around an accident scene it creates an uncordinated mass of flashing lights with each set flashing out of sync with all the others. This becomes very confusing for drivers approaching the accident and is also very dangerous for emergency workers who may not be seen through the glare as they move around the site. Switching most of the vehicles down to ambers definitely improves scene safety by reducing flash irritation and glare although the full safety issue while on-scene is somewhat more complicated than this!

      Research into motorcycle conspicuity has demonstrated that a triangular combination of white lamps with the headlight at the apex enhances forward visbility in traffic. Spatial awareness is increased by providing a stable linked group of reference points for other drivers. Unfortunately side facing white lamps would probably disorient and confuse other drivers. They are also illegal in most jurisdictions as most emergency types of white light-head produce excessive glare. It will always be very difficult to successfully and effectively fit warning lights to the very limited space available on motorcycles.
      I hope this helps….


  3. SoccerDadof22 says:

    Years ago, when strobe lights were the newest technology, the Pennsylvania (USA) State Police had to brightness settings. High-brightness was for day use, and low(er) brightness was for night use. This simple approach greatly reduced the perceived ‘close calls’ of troopers nearly getting hit by passing drivers. I wish the same approach were taken with today’s LED lighting. They are far too bright and can lead to temporary blindness for nearby drivers – leading to more accidents and decreased safety.

    As a former firefighter, the more traditional rotating incandescent lights offered safety and adequate emergency illumination. Additionally, their rotating nature also gave people additional position information that their brain subconsciously processed that doesn’t exist with modern solid-state lighting. At the end of the day, newer and more efficient does not mean better.


  4. Steve Black says:

    Problem has gotten worse since Detroit jumped on the band wagon, with emergency vehicles now emitting intense flashing blue light from every pore. I didn’t see an officer directing traffic the other night until I was almost on top of him, saw his flashlight at the last minute. Dark uniform and intense blue flashing lights from multiple units. Very disorienting, and isn’t good for the officers night vision as well.


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