Should the fleet investigate the use of vehicle safety markings?
Are we absolutely certain that our emergency and delivery vehicles are as safe as they could be?
Mediafleet has recently been shortlisted for the Innovation Award at the 2022 What Van Awards. The award application was based on the work Mediafleet provided for Southern Water, and other companies, where reflective graphics were required for the vehicle branding – alongside the normal Chapter 8 markings. The benefit of reflective graphics is that the branding can be easily seen at night as the logos and lettering ‘glow’ in the dark. It means that the branding works at all times of the day in promoting your brand. The other benefit is that the increased visibility improves safety both for the driver and the general public.
And that got me thinking about the effectiveness of UK safety markings.
After a little bit of digging around, it appears there is some debate about the best format for safety markings.
The subject of vehicle safety markings is complex with efficacy being based on physical size of the target, colour and reflectivity, patterns and lighting conditions. All of these physical properties are then subject to interpretation by approaching road users, significantly complicating the issue.
The American psychologist, P R Killeen, stated that conspicuity comprises the following elements:
Physical Conspicuity: the ability of an observer to detect a target in a brief presentation, this relates to body colour, shape and markings
Cognitive Conspicuity: the ability to recognise and process what is seen
Visibility: the ease of identifying the object
Recognition: the ability to interpret the particular shapes and colours of the object.
Some visibility markings actually make recognition less effective, with haphazard or complex marking designs inducing camouflage effects in complex environments or low lighting conditions.
Killeen also highlights some ‘awareness factors’ between subject vehicles and the background environment, including:
- Vehicle speed
- Apparent visual size: maximised through appropriate vehicle markings
- Shape: communicating vehicle type and orientation
- Colour: some colours can be seen more quickly than others in an urban environment, with fluorescence enhancing this effect further
- Brightness: effect is maximised at dawn and dusk, during adverse weather conditions and under low light conditions.
In short, all these are factors are affecting the ability to recognise what is actually in front of you.
Clearly, emergency response vehicles are the most vulnerable; travelling at speed and standing still by the roadside. That combined with the distraction of the incident and the following lack of awareness of some drivers puts them in the high-risk category.
White is the safest colour for vehicles…right?
Not according to Killeen, this is the most conspicuous base colour for a vehicle:
Because a light source radiating 1 W of green light will appear much brighter than another source radiating the same amount of power of red light because the eye is more sensitive in the green region. The human eye is sensible to light wave which wavelength is roughly between 400 nm (violet) and 700 nm (red). Wavelengths shorter than 400 nm (ultraviolet, UV) or longer than 700 nm (infrared, IR) are not visible.
Plus, the eye behaves differently in high or low light conditions. In daylight, for brightness levels above a certain level, the vision is mainly done by the centre of the retina, we can see colours and the maximum sensitivity is at 555 nm (in the green region). Which is why the green panel above is most visible in daylight. This type of vision is called photopic vision.
In low light conditions, for low brightness levels, the vision is mainly done by the peripheral region of the retina which is colour-blind. The centre region is not sensitive enough to see any colour. This type of vision is called scotopic vision. Maximum sensitivity is at 507 nm (in the blue-green region) and red light is almost invisible.
Solid Colours Can Play Tricks
According to Killeen (2010), dark colours adjacent to one another (such as red and blue) cause visibility problems with the eye not able to easily lock focus with such combinations. You may have seen the Mediafleet article on iconic motorsport branding when we discussed the Gulf branding that demonstrated Equi luminance – great for interesting daylight branding, perhaps not so good for safety markings.
Good Colours Combinations for Safety Markings
Killeen recommended the following body colours and combinations as suitable for emergency vehicle use:
- Chrome or Euro Yellow
- White and fluorescent yellow-green
- White and fluorescent red
- Fluorescent red
Solomon and King (1995) in the USA studied visibility-related crashes of fire engines in Dallas, Texas, where the fleet of formerly red or red/white fire units was replaced by yellow-green/white vehicles. They found that crash rates of all severity levels were 3.5 times higher among red vehicles, with injury crashes higher by a statistically significant factor of 6.5.
Do Chapter 8 Rear Chevrons Work Well?
Chevrons have been widely applied to the rear of commercial vehicles, but appear to have a number of pitfalls. Usually applied as an inverted-’V’ to the vehicle rear only, the intention is to encourage approaching vehicles around each side. However, according to Killeen, they can blur body edge discrimination and disrupt distance perception. Killeen also suggested that the way the eye works, which is by scanning horizontally, leads to slower recognition of vertical or diagonal patterns. Another scientist and his team (L Tijerina et al (2003)) separately agreed that multi-colour rear end chevron markings may actually reduce conspicuity by camouflaging the rear of the vehicle!
What About the Sides of Vehicles?
Tested in New Brunswick, Canada by a wide sample group to represent the profile of licensed drivers in the province, a continuous white stripe of reflective tape around the perimeter of a trailer was found to be the most effective of a selection of nine different marking schemes. The European Commission has a specific standard, UNECE R104, which specifies stripes of 50-60 mm width covering not less than 80% of the vehicle length in retroreflective white, yellow or red.
Reflective Graphics on Vehicle Sides
Now, I’m no expert on this but looking at the above data, findings and research, it appears that adorning the side of a vehicle with reflective graphics could provide additional safety margins. In daylight, providing the colours don’t clash, the graphics will enhance visibility and give a perspective of vehicle size. At night, the reflected white light will be easily seen by the human eye and therefore the vehicle will be more visible leading to enhanced safety. I am not suggesting that the usual contour graphics be replaced by this, quite the opposite in fact, where it could be used to perhaps ‘frame’ the branding graphics.
From the brief research I have conducted, I think that it may be prudent to conduct more work regarding the efficacy of safety markings. There seems to be some conflicting opinion and bearing in mind how important this topic is in protecting drivers and the general public, I think maybe, this should be looked at again…by scientists who can guide our fleet managers and graphics companies.