Visibility aids for pedestrians and cyclists: a systematic review of randomised controlled trials
Introduction
Road traffic crashes account for over a million deaths and some 10 million permanent disabilities a year worldwide (Murray and Lopez, 1996). Nearly three-quarters of road deaths occur in low and middle-income countries (Odero et al., 1997), predominantly as a result of cycle and pedestrian injuries. In 2000, there were 42,033 pedestrian and 20,612 bicyclist casualties in the UK (DETR, 2001).
One of the basic driver errors responsible for collisions is the late detection of other road users (Rumar, 1990). Pedestrian casualties are over-represented at night, partly due to reduced visibility (Owens and Sivak, 1993). Night time cycling is two–five times more dangerous than cycling in daylight and 40% of the bicyclists fatalities occur during the hours of darkness (Jaermark et al., 1991).
Walking and cycling are essential modes of travel for many in low and middle-income countries, and are also promoted for their environmental, economic and health benefit. Visibility aids such as reflective garments enhance the conspicuity of the pedestrians and cyclists, thus attracting the driver’s attention to their presence. The efficiency of visibility aids depend on whether they can visually alert the drivers in time to avoid a collision. Many factors affect conspicuity, including object contrast, size, movement, illumination, background ‘clutter’ and road condition, also the cognitive process of the driver and his/her responses in detection and recognition. To assess the effect of visibility aids on pedestrian and cyclist safety and on drivers’ responses in detection and recognition, we conducted a systematic review of randomised controlled trials of visibility aids.
Section snippets
Identification and selection of trials
We identified relevant randomised controlled trials and controlled before-and-after trials from 1963 to May 2001 by computerised searches of the Cochrane Controlled Trials Register, the specialised register of the Cochrane Injuries Group, MEDLINE, TRANSPORT, National Research Register and PsycINFO. A randomised controlled trial was defined as a trial in which the subjects were assigned prospectively to one of the two (or more) interventions by random allocation or some quasi-random method of
Results
Our search strategy found 1991 potentially eligible reports (Fig. 1). We did not find any trials quantifying the effect of visibility aids on the occurrence of pedestrian and cyclist–motor vehicle collisions and injuries. However, we identified 29 papers reporting 37 trials which assessed the effect of visibility aids on drivers’ and observers’ responses in detection and recognition, involving 882 participants aged between 17 and 77 years. These 37 trials were conducted in seven countries and
Discussion
We did not find any randomised controlled trials or controlled before-and-after trials which compared the effect of visibility aids on the occurrence of pedestrian and cyclist–motor vehicle collision. The effect of visibility aids on pedestrian and cyclist safety therefore remains unknown. However, results of the trials reviewed do suggest that visibility aids influence drivers’ reaction, detection and recognition. For daytime, fluorescent materials in yellow, red and orange colours improved
Acknowledgements
A full version of this review (Kwan and Mapstone, 2002) has been published in the Cochrane Library, where it will be regularly updated to take account of new data and comments. Contributors: Irene Kwan and James Mapstone independently screened the electronic search results, applied inclusion criteria and extracted data. Irene Kwan developed the protocol, contacted authors, entered data into RevMan and wrote the review. James Mapstone commented on the review and helped to write the review. We
References (39)
- et al.
Experimental evaluation of alternative conspicuity-enhancement techniques for pedestrians and bicycles
J. Saf. Res.
(1986) - et al.
Effects of experience with retroreflectors on recognition of nighttime pedestrians: comparison of driver performance in Finland and Michigan
Transportation Res.
(1998) - et al.
Effects of retroreflector positioning on nighttime recognition of pedestrians
Accident Anal. Prev.
(1996) - et al.
Identifying controlled evaluation studies of road safety interventions: searching for needles in a haystack
J. Saf. Res.
(2001) - et al.
Actual pedestrian visibility and the pedestrian’s estimate of his own visibility
Am. J. Optometry Arch. Am. Acad. Optometry
(1970) - et al.
Reflectorisation for nighttime conspicuity of bicycles and motorcycles
J. Saf. Res.
(1978) - et al.
A field trial of attention and search conspicuity
Hum. Factors
(1984) - CPSC, 1997. The Bicycle Reflector Study Data: The Effect of Helmet Reflectivity...
- DETR, 2001. Transport Statistics Bulletin. Road Casualties in Great Britain: Main Results 2000...
- Gale, A.G., Cairney, P., Catchpole, J., 1996. Patterns of perceptual failures at intersections of arterial roads and...
Vision, visibility and perception in driving
Perception
Can the conspicuity of objects be predicted from laboratory experiments?
Ergonomics
Visible distances in simulated night driving conditions with full and dipped headlights
Ergonomics
Safety clothing for human traffic obstacles
Ergonomics
Cited by (65)
The effect of rear bicycle light configurations on drivers’ perception of cyclists’ presence and proximity
2024, Accident Analysis and PreventionHow do bicyclists respond to vehicles with adaptive headlamp systems? A nighttime study in an immersive virtual environment
2024, Journal of Safety ResearchSafety in fluorescent numbers: An observational study on speeding
2022, Journal of Transport and HealthMacro-level literature analysis on pedestrian safety: Bibliometric overview, conceptual frames, and trends
2022, Accident Analysis and PreventionUsing latent class clustering and binary logistic regression to model Australian cyclist injury severity in motor vehicle–bicycle crashes
2021, Journal of Safety ResearchCitation Excerpt :By increasing the visibility and conspicuity of cyclists, they may be more easily recognized and subsequently avoided by drivers when scanning the road scene. Further, the ability of drivers to respond in time is greater when cyclists or pedestrians make use of visibility aids (Kwan & Mapstone, 2004). Also, increased cyclist visibility can have important implications regarding the severity of injuries suffered in the event of a crash.