Road traffic fatalities by light conditions: a comparative analysis between the US and the UK

Introduction

The number of pedestrian fatalities in the United States has risen steadily since 2009 (Sanders, Schneider, and Proulx 2022; Ferenchak, Gutierrez, and Singleton 2022; Wang and Cicchino 2020). A key risk factor in these pedestrian deaths is darkness (Ferenchak, Gutierrez, and Singleton 2022; Sanders, Schneider, and Proulx 2022). Despite less pedestrian flow at night, three-quarters of pedestrian fatalities in the US occur in the dark. Also, the rate of pedestrian deaths in the dark in the US is increasing.

Several questions arise:

Is the number of fatality cyclists increasing as much as the number of pedestrians? And how does the darkness influence fatality in cyclists?
Is the increase in pedestrian fatalities and darkness a trend unique to the US or is it also happening in other Western countries like the United Kingdom?

Using road safety data and travel data from the US and UK, this study estimates and compares trends in the risk of travelling in the dark by modes of transport (pedestrians, cyclists, and other road users) between the US and the UK.

Data and method

Data

Road safety data

US Fatality Analysis Reporting System (FARS) data – National Highway Traffic Safety Administration (NHTSA)
UK Road Safety Data (STATS19) – Department for Transport (DfT)

Travel data

US National Household Travel Survey – Federal Highway Administration (FHWA)
UK National Travel Survey – DfT

Method

$$ \text{Risk ratio (dark)} = \text{num. fatalities (dark)}/\text{Bkm travelled (dark)}$$

Results

Road traffic fatalities by light conditions and type

US 2011-2020 (FARS data)

Table 1. Road traffic fatalities by light conditions and type, US 2011-2020

Type	Light conditions	Light conditions in detail	Num.	%
Pedestrians	Daylight	Daylight	7676	20.96
Pedestrians	Dark	Dark - Lighted	14316	39.09
Pedestrians	Dark	Dark - Not Lighted	12821	35.00
Pedestrians	Dark	Dark - Unknown Lighting	472	1.29
Pedestrians	Dark	Dawn	603	1.65
Pedestrians	Dark	Dusk	739	2.02
Cyclists	Daylight	Daylight	2482	48.33
Cyclists	Dark	Dark - Lighted	1257	24.47
Cyclists	Dark	Dark - Not Lighted	1110	21.61
Cyclists	Dark	Dark - Unknown Lighting	43	0.84
Cyclists	Dark	Dawn	103	2.01
Cyclists	Dark	Dusk	141	2.75
Others	Daylight	Daylight	94891	52.80
Others	Dark	Dark - Lighted	27897	15.52
Others	Dark	Dark - Not Lighted	47816	26.61
Others	Dark	Dark - Unknown Lighting	1092	0.61
Others	Dark	Dawn	3527	1.96
Others	Dark	Dusk	4495	2.50

Figure 1. Road traffic fatalities by year and type, US 2011-2020

Figure 2. % of road traffic fatalities by light conditions, year, and type, US 2011-2020

UK 2011-2020 (STATS19 data)

Table 2. Road traffic fatalities by light conditions and type, UK 2011-2020

Type	Light conditions	Light conditions in detail	Num.	%
Pedestrians	Daylight	Daylight	1985	46.00
Pedestrians	Dark	Darkness - lights lit	1466	33.97
Pedestrians	Dark	Darkness - lights unlit	79	1.83
Pedestrians	Dark	Darkness - no lighting	705	16.34
Pedestrians	Dark	Darkness - lighting unknown	80	1.85
Cyclists	Daylight	Daylight	808	74.13
Cyclists	Dark	Darkness - lights lit	157	14.40
Cyclists	Dark	Darkness - lights unlit	10	0.92
Cyclists	Dark	Darkness - no lighting	110	10.09
Cyclists	Dark	Darkness - lighting unknown	5	0.46
Others	Daylight	Daylight	7446	61.81
Others	Dark	Darkness - lights lit	1859	15.43
Others	Dark	Darkness - lights unlit	93	0.77
Others	Dark	Darkness - no lighting	2450	20.34
Others	Dark	Darkness - lighting unknown	199	1.65

## `summarise()` has grouped output by 'YEAR'. You can override using the
## `.groups` argument.

Figure 3. Road traffic fatalities by year and type, UK 2011-2020

## `summarise()` has grouped output by 'YEAR', 'Type'. You can override using the
## `.groups` argument.

Figure 4. UK % of road traffic fatalities by light conditions, year, and type, UK 2011-2020

Dicusssion

Conclusions

References

Ferenchak, Nicholas N., Risa E. Gutierrez, and Patrick A. Singleton. 2022. “Shedding Light on the Pedestrian Safety Crisis: An Analysis Across the Injury Severity Spectrum by Lighting Condition.” *Traffic Injury Prevention* 23 (7): 434–39. .

Sanders, Rebecca L., Robert J. Schneider, and Frank R. Proulx. 2022. “Pedestrian Fatalities in Darkness: What Do We Know, and What Can Be Done?” *Transport Policy* 120 (May): 23–39. .

Wang, Jin, and Jessica B. Cicchino. 2020. “Fatal Pedestrian Crashes on Interstates and Other Freeways in the United States.” *Journal of Safety Research* 74 (September): 1–7. .

saturnlighting / road-traffic-fatalities-by-light-condition

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