Lighting for Night Driving within the Urban Context

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Zhuofei Ren

N00336663

12/10/2013

Lighting for Night Driving within the Urban Context

Night driving has arisen as a critical issue for the society. Lighting in night driving is

essential for the driver’s orientation and detection. Nowadays high-performance

automobile lamps have been designed and used with the development of modern

automotive industry. Driving manners regarding how to use lighting equipment have been

added to driver’s manuals to avoid accidents. However, the strategies to ensure night

driving safety should not just focus on the quality of automobile lighting and by regulating

driver’s behaviors. More efforts should be made for the interaction between automobile,

pedestrians, streets, near-road buildings and the night time city. The lighting condition in

night time driving is complicated with changing variations. Lighting for night driving

should be planned with comprehensive consideration of multiple factors and carefully

designed to achieve a safe, discernible and harmonious night time environment.

For long people’s idea to improve night driving condition have been focused on the

performance of automobile lighting and the drivers’ awareness to enhance night driving

safety. From 1906 till now, the automobile headlights have been rapidly developed from

the candle, incandescent, halogen, high intensity discharge to LED.1 The life span is

getting longer and the intensity of the lamps has increased as twice as it was before.2 To

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great extent people are relying on automobile lighting for night driving. In most areas

within the United States, the highway is not installed with street lights, which are

considered as costly in money and could cause distraction from the driver. Instead, the

headlights are seen as only effective tools for illuminating the highway at night.

On the other hand, instructions regarding driving manners at night have been

incorporated in the driving manual in each state. The NYS Driver’s Manual_MV21

mentions that the law requires the driver to use the headlights when visibility is less than

1,000 feet.3 The headlights must be on low beam when the driver is within 500 feet of an

oncoming vehicle or within 200 feet of vehicle ahead.4 If light from street lights makes it

hard for the driver to see the road, the driver is supposed to adjust the visors to reduce

glare from the street lights above.5

However the limitation of drivers’ ability for detection at night cannot be solved just by

improving the performance of automobile lighting and regulating driver’s manners. There

are unpredictable cases that are not controlled by any rules or technologies. For example,

for driving on the highway, there would be some cases that some animals cross the road

or the weather turn to be undesirable. Also, when automobile increases the speed, the

driver’s vision angle will become narrower. When the driver switches from the high beam

to low beam for oncoming cars or crossing pedestrians, the eyes will appear blind for a

short time, which takes several seconds for adaptation.6 Furthermore, within a day the

driver’s mental state varies from time to time.7 At night the driver would easily become

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fatigue and distracted.8 At late night he or she would become even more fatigued

because of biological clock. Meanwhile the driver would also become less vigilant by

relying on the advanced headlights and assuming less activities on road during the

night.9

Besides the driver and the automobile, there are a variety of objective factors in the

surrounding environment that also have impacts on night driving. A study named “Effects

of the viewing context on target detection” uses The Small Target Visibility (STV) model

as a reference to “evaluate the impact of the complex background and apparent motion

on the driver’s target detection performance in mesopic vision”.10 It appears that both the

spatial context and the apparent motion will negatively impact the driver’s ability to detect

peripheral target.11 The more dynamic or informative the context is, the poorer the

driver’s detection is. The streets, public spaces and people’s movements are key

elements that contribute to the complexity of the environment. Light pollution, road

lighting and pedestrians are three main variations showing impacts of the environment on

night driving.

Light pollution in the city is a major factor that affects the driver’s concentration.

Today some highly industrialized and densely populated areas in the United States are

having a problem of light pollution--an excessive illumination from building exterior and

interior lighting, advertising, commercial properties, offices, factories, streetlights, and

illuminated sports venues. These autonomous lighting from different organizations have

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become random factors within the city and “those responsible for it don’t take into

account all the other light that is present in the city, from illuminated buildings and all

kinds of incidental situations that produce light.”12Glare, which is one type of light

pollution, would cause loss of contrast and leads to unsafe driving conditions. Another

type of light pollution-light clutter caused by street lights and advertising surrounds the

roadways intend to distract the drivers as well.

The road lighting is another factor within the context. The poor design of street light

can lead confusion or distraction for drivers. The inappropriate lamp intensity or paving

materials would cause glare for the driver. The street light with poor capability to

penetrate fog will impair the driver’s judgment, reaction speed and intensify the driver’s

mental strain. But on the other hand, if without the road lighting at all, the driver’s vision

would be limited within the range that the headlights could reach. The strong contrast

between the background and the target will impair the driver’s detection for periphery

environment. Therefore a good design for road lighting is a key to balance the luminance

level and create harmony environment. Due to the complexity of the road situations, it is

difficult to compare different cases and generalize a principle to improve the road lighting

for night driving.

Another factor affects night driving in the context is the pedestrian. For the driver, it is

essential to be aware of the pedestrian’s existence and movement. According to a recent

study, the driver’s ability to recognize pedestrians at night is based on the driver’s age,

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pedestrians’ clothing configuration, headlamp beam and the glare.13 The study shows

that pedestrians wearing in black are most challenging to be seen while those wearing

retroreflective clothing are most apparent in vision.14 The result implies a new way to

think about garment designs for walking people that benefit night time drivers.15 On the

other hand, from the pedestrian’s perspective, the automotive lighting condition is also

critical for them to detect the traffic. As the driver would suffer from the glare, distraction

and short time blindness due to the changing light conditions outside of the cars,

pedestrians will experience the similar problems from the automobile lighting at the same

time. Only when people have a clear sense of orientation, should they choose the right

way and time to walk. This will in turn minimize the conflicts between the automobiles and

the pedestrians.

As mentioned above, there are a variety of factors affecting night driving, more

flexible solutions for a comfortable and safe driving condition should be established to

adapt to the changes. According to the article Light Zone City: Light Planning in the

Urban Context, “in many European countries there are guidelines for public lighting.”16

The European norm called Standard EN-13201 regarding road lighting has been

established in 2008. It categorizes the wide variety of traffic situations into different

classes, defines road luminance parameters and specifies the measurement of lighting

installations.17 The selection of the class is decided by the number of cyclists and the

need for recognition of faces.18

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Moreover, in terms of relationship between automobile lighting and road lighting,

some studies have been focused on the combining effort of the two systems. In a recent

study about optimization of luminous environment by simulating traffic lighting, an

advanced measuring tool-ProMetric 1400 for road lighting luminance measurements is

used to analyzes “the lighting conditions in night-time traffic, where both the fixed road

lighting and automobile lighting are contributing to the luminance scene.19 It is based on

the methods of luminance calculations and measurements from the European guideline

EN13201-3.20 This measuring method can be used to “control and secure the quality of

road lighting installations”.21 Meanwhile a CAD software for simulation of automobile

headlight reflector and lens is suggested to use in the real scene, where the geometric

data of the standard road will be input to the computer for simulation.22 “The database

contains all complex processes such as absorption, scatter, reflection, etc”.23 This

simulation tool can help the design process to be more efficient with decreases in costs

and the developing period.24 The study eventually concludes that it “is important to

consider the combined effect of fixed road and street lighting and automobile lighting

when analyzing and optimizing the visual environment in night-time driving.”25

From the result of the studies, the potential has been seen to combine the design of

automobile lighting and road lighting with simulation to ensure the safety of night driving.

A more automated and interactive program to adjust lighting to the specific condition and

unexpected changes at night is expected to be developed in the future.

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Some other suggestions are going to be discussed in the following for further

development of lighting for night driving.

In addition to the high technology of lighting system, adjustable programs could be

set up to help the driver to get through the unavoidable physiological phenomena. For

example, in order to address the issue of short time blindness when shifting between

headlight beams, there could be a transition phase to allow extra time for eye adaptation.

Also since the driver’s vision field is narrowing with the speed increases, the headlights

could be designed more intelligent to recognize the change of speed and adjust the

intensity or range of the beam to compensate the change of the driver’s view.

Another perspective for automobile lighting design is to think from the outside of the

automobiles. From the view of city planning, automobile lighting should be considered in

a similar way with that for building illumination. Like architecture, the automobile provides

an enclosed private space for the passenger and the driver. It also has a façade which

should be easily identified from outside. It is as the micro moving architecture shuttling

within the urban environment. Therefore some guidelines for illumination of buildings

could also be applied to design the automobile lighting. In the article Light Zone City:

Light Planning in the Urban Context, the author talks about general principle for building

illumination: The illumination should not have a disturbing effect on the surroundings or

strike any false notes;26 “One illumination should not be allowed to overwhelm

another”;27 “More light is not always better, particularly when it increases contrasts”;28

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“…not only the façade should be illuminated, but the depth should also be

accentuated”;29 “In general, the lighting of buildings must be moderate”, etc.30 If these

suggestions from architectural lighting could be applied to automobile lighting, the identity

of vehicles would be enhanced and a more balanced and aesthetic lighting effect would

be realized. Hence people walking at night will feel easy and comfortable to detect the

orientation and movement of vehicles, which will in turn ensure the safety of night driving.

“Lighting for night driving is essential to create an optimal visual environment and to

ensure the safety for road users.”31 Right now the methods on how to keep a good

lighting condition for night driving are limited, among which are to apply

high-performance headlights to automobiles and to regulate the driving manners by

manuals or laws. Some opinions on the road lighting points out that it is unnecessary to

install road lighting for highway due to the distraction from the driver and the huge cost.

There has been little effort to combine the effect of automobile lighting, the road lighting

and the lighting planning for the city. In order to make the design and dimensioning of

lighting more efficient and optimal for road users, urban planners, lighting designers and

engineers should consider human factors at night time as well as the interactions

between lighting, automobiles, people and the context. Some recent guidelines and

studies have been established to set up standard methods for luminance measurements

and calculations and correspondingly incorporate these parameters to the design of

headlight reflectors and lens. These achievements provide a guide for further

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development of intelligent lighting system taking into account the factors of the driver, the

automobile, the pedestrians and the environment are able to adapt to changes in the

context. Another aspect to think about lighting for night driving is from the perspective of

the pedestrians or from the urban environment outside of the automobiles, which is

considered as a macro moving architecture that some of the strategies for building

illumination could also be applied to. With all these efforts to improve lighting for night

driving, some efficient, economic solutions could be proposed to enhance safety and

orientations for users and provide a comfortable lighting environment for the whole

circumstance.

Endnotes

1 Yu Shiqiang, "Introduction of Automobile Lighting History and Related Knowledge." 09

21, 2009.Trans. Zhuofei Ren Accessed December 05, 2013.

http://news.bitauto.com/qichezhishi/20090921/1005041269.html. 2 lbid 3 Office of Communications, New York State Departement of Motor Vehicles, "NYS

Driver’s Manual_MV21." Last modified 10 2011. Accessed December 3, 2013.

http://www.dmv.ny.gov/broch/MV21.pdf for the Internet 10/2011.82. 4 lbid., 83. 5 lbid., 83. 6 Yun Liu, and Cailiang You, "Safety and Hazard Analysis of Night Driving," Safety and

Health, 8 (2006): 23-24, Trans. Zhuofei Ren

http://www.cqvip.com/QK/86710X/200608/22638781.html (accessed December

08, 2013). 7 Xiaofeng Fu, "Potential Accident Analysis of Night Driving." Road Traffic Management.

3 (2000). Trans. Zhuofei Ren

http://www.cnki.com.cn/Article/CJFDTotal-DLJG200003009.htm (accessed

December 05, 2013). 8 lbid. 9 lbid.

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10 Mayeur, Anais, Roland Bremond, and J.M. Bastien Christian. "Effects of the viewing

context on target detection. Implications for road lighting design." Applied

Ergonomics. no. 3 (2010): 461.

http://www.sciencedirect.com/science/article/pii/S0003687009001379 (accessed

December 2, 2013). 11 lbid., 467. 12 Christa Santen, Light Zone City: Light Planning in the Urban Context, (Basel:

Publishers of Architecture, 2006), 40. 13 Joanne Wood, Richard Tyrrell, and Trent Carberry, "Limitations in Drivers' Ability to

Recognize Pedestrians at Night," Human Factors: The Journal of the Human

Factors and Ergonomics Society , 47, no. 3 (2005): 644,

http://hfs.sagepub.com/content/47/3/644.short (accessed December 3, 2013). 14 lbid 15 lbid 16 Santen, 40. 17 lbid. 18 lbid.,43. 19 Aleksanteri Ekrias, Marjukka Eloholma, Liisa Halonen, Xian-Jie Song, Xin Zhang, and

Yan Wen, "Road lighting and headlights: Luminance measurements and

automobile lighting simultions," Building and Environment, 43, no. 4 (2008): 531,

http://www.sciencedirect.com/science/article/pii/S0360132307000157

(accessed December 1, 2013). 20 lbid., 530. 21 lbid., 531. 22 lbid., 534. 23 lbid. 24 lbid. 25 lbid., 535. 26 Santen., 72. 27 lbid., 74. 28 lbid. 29 lbid., 78. 30 lbid. 31 Mayeur, Bremond, Bastien, 535.

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Bibliography

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of Architecture, 2006.

Mayeur, Anais, Roland Bremond, and J.M. Bastien Christian. "Effects of the viewing

context on target detection. Implications for road lighting design." Applied

Ergonomics. no. 3 (2010): 461-468.

http://www.sciencedirect.com/science/article/pii/S0003687009001379 (accessed

December 2, 2013).

Ekrias, Aleksanteri, Marjukka Eloholma, Liisa Halonen, Xian-Jie Song, Xin Zhang, and

Yan Wen. "Road lighting and headlights: Luminance measurements and

automobile lighting simultions." Building and Environment. no. 4 (2008): 530-536.

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Wood, Joanne, Richard Tyrrell, and Trent Carberry. "Limitations in Drivers' Ability to

Recognize Pedestrians at Night." Human Factors: The Journal of the Human

Factors and Ergonomics Society . no. 3 (2005): 644-653.

http://hfs.sagepub.com/content/47/3/644.short (accessed December 3, 2013).

Liu, Yun, and Cailiang You. "Safety and Hazard Analysis of Night Driving." Safety and

Health. (2006): 23-24. Trans. Zhuofei Ren.

http://www.cqvip.com/QK/86710X/200608/22638781.html (accessed December

08, 2013).

Fu, Xiaofeng. "Potential Accident Analysis of Night Driving." Road Traffic Management.

3(2000). Trans. Zhuofei Ren.

http://www.cnki.com.cn/Article/CJFDTotal-DLJG200003009.htm (accessed

December 05, 2013).

Shiqiang, Yu. "Introduction of Automobile Lighting History and Related Knowledge." 09

21, 2009.Trans. Zhuofei Ren Accessed December 05, 2013.

http://news.bitauto.com/qichezhishi/20090921/1005041269.html.