Use of retro-reflective clothing

A Transport Canada study of fatally injured vulnerable road users found that 59% of pedestrians killed in crashes in Canada between 2004 and 2006 were stuck in dim lighting conditions (dawn or dusk) or darkness (Transport Canada, 2009). An Ontario study on pedestrian fatalities indicated that twilight or darkness conditions existed for 57% of fatal pedestrian crashes in the province in 2010 (Ontario Ministry of Community Safety and Correctional Services, 2012).

Pedestrians who are more visible are less likely to be struck. Retroreflective material, which passively reflects light back in the direction of its source, enhances conspicuity for pedestrians and increases the opportunity for drivers to detect and avoid them sooner, especially at night.

Luoma et al. (1995) conducted a field study to investigate the potential effects of retroreflector positioning on recognition of pedestrians at night. The study required subjects to press a response button when they recognized a pedestrian on or alongside a dark road, while in a car with low-beam lamps on that was driven at a constant speed. Four retroreflector configurations were tested for pedestrians who were either approaching or crossing the road. The configurations included no retroreflector, torso, wrists and ankles, and major joints. The results of the study showed that the mean recognition distance was 40 metres when no retroreflectors were used, 96 metres for torso reflectors, 156 metres for wrist and ankle reflectors, and 169 metres for major joints reflectors when a pedestrian approached the subject vehicle. When a pedestrian crossed the road, the corresponding recognition distances were 35, 136, 241, and 249 metres, respectively. The results of the study demonstrated that pedestrians were identified much sooner for all of the retroreflector configurations than when no retroreflector was used. The retroreflective markings attached to the pedestrian’s limbs resulted in significantly longer recognition distances than when the markings were attached to the torso. The study also showed that pedestrians who wore retroreflectors were seen more easily while crossing the road than while walking on the side of the road (Luoma et al., 1995).

Wood et al. (2003) conducted an experiment to assess the ability of young and older drivers to detect pedestrians at the roadside at night. Ten young (mean age 27.8 years) and ten older (mean age 67.9 years) drivers drove around a closed road circuit at night and pressed a button whenever they recognized a pedestrian. Four pedestrian clothing conditions were tested for the experiment – black, white, retroreflective vest, and retroreflective material in the biomotion configuration - in both low and high beam conditions. The results of the experiment showed that 61% of drivers identified pedestrians in the presence of glare when the headlights were on low beam and 76% in the absence of glare. Only 5% of pedestrians who wore dark clothing were identified in the glare condition. Only 48% of older drivers identified the pedestrians in the presence of glare conditions compared with 75% of younger drivers. Overall, the pedestrian recognition distances for the older drivers were 58% of those of the younger drivers. When the pedestrian wore retroreflective material in the biomotion configuration in the absence of glare, they were seen 100% of the time by both the young and the older drivers. In the presence of glare, pedestrians were recognized by 100% of the young drivers and 75% of the older drivers. The authors noted that recognition distances for pedestrians who wore retroreflective material in the biomotion configuration were improved by as high as 52 times when compared with the pedestrian wearing black clothing (Wood et al., 2003).

Tyrrell et al. (2006) conducted an experiment in open-road conditions to determine the effects that the number of reflective elements and natural pedestrian motion had on pedestrian conspicuity. Study participants were driven along a residential route at night and pressed a button when they saw a pedestrian. Pedestrians either stood still or walked in place on the right side of the road and wore black clothing or black clothing plus 304 cm2 of retroreflective material in one of four different configurations. The results of the study showed that when pedestrians were walking, all conditions with retroreflective markings on the extremities were significantly more conspicuous than the black condition (30.6 metres), with spotting distances ranging from 88.9 metres for ankles to 113.5 metres for biological motion. The authors concluded that placing retroreflective markings on the major joints of pedestrians contributed to enhanced conspicuity and that both form perception and motion perception contributed to this benefit (Tyrrell et al., 2006).

Kwan et al. (2009) carried out a Cochrane Review of 42 studies to quantify the effect of different visibility aids on pedestrian and cyclist crashes and casualties, and on drivers’ detection and recognition of these vulnerable road users. The authors did not find any studies that assessed the effect of visibility aids on pedestrian or cyclist crashes or injuries. However, the authors found studies that showed that fluorescent materials in yellow, red and orange colours improved driver detection of pedestrians during the daytime, while lamps, flashing lights, and retroreflective materials in red and yellow, particularly those with a biomotion configuration that took advantage of the motion from a pedestrian’s limbs, improved pedestrian recognition at night (Kwan et al., 2009).

Graving et al. (2009) conducted an on-road study to test the impact of retroreflected luminance on pedestrian conspicuity in the presence or absence of biological motion. Study participants pressed a button when they saw a pedestrian walking in place or standing on the shoulder of a dark road while wearing black clothing plus 200 cm2 high, medium, or low intensity retroreflective material that was either placed on the torso or the wrists and ankles. Response distances were significantly greater when the pedestrian was walking and wearing retroreflectors on the wrists and ankles (119 metres) than when walking and wearing retroreflectors on the torso (24metres). Participants observed the walking pedestrian wearing the high intensity retroreflectors at a marginally significantly greater distance (92 metres) than the walking pedestrian wearing the low intensity retrorefletors (47 metres). Responses to the standing pedestrian wearing retroreflectors on the wrists and ankles were not significantly greater than responses to the standing pedestrian wearing retroreflectors on the torso. The authors concluded that the presence of biological motion had a greater impact on increasing pedestrian conspicuity than increasing retroreflective intensity (Graving et al., 2009).

Wood et al. (2011) conducted an experiment at two open-road work sites at night-time to determine if the conspicuity of road workers at night could be enhanced through wearing clothing that had retroreflective strips across the body in a biomotion configuration. The study involved four road workers walking in place wearing a standard road worker night vest either alone, with additional retroreflective strips on thighs, with additional retroreflective strips on ankles and knees, or with additional retroreflective strips on eight moveable joints (full biomotion). Participants in stationary vehicles rated the workers’ conspicuity from three distances. The results showed that road worker conspicuity was maximized by the full biomotion configuration at all distances and at both sites (Wood et al., 2011).

Scope of the Problem

• Transport Canada (2009). Fatally Injured Vulnerable Road Users in Canada, 2004-2006. Road Safety and Motor Vehicle Regulation Directorate, Transport Canada. Retrieved from http://ccmta.ca/images/pdf-documents-english/rsrp/STRID/VRU/tc_vru_report_april_09.pdf
• Ontario Ministry of Community Safety and Correctional Services (2012). Pedestrian Death Review, A Review of All Accidental Deaths in Ontario From January 1st 2010 to December 31st 2010. Office of the Chief Coroner of Ontario. Retrieved from http://www.mcscs.jus.gov.on.ca/english/DeathInvestigations/office_coroner/PublicationsandReports/PedestrianDeathReview/DI_Pedestrian_Death_Review.html

Evidence

• Luoma, J., Shumann, J., & Traube, E.C. (1995). Effects of retroreflector positioning in nighttime recognition of pedestrians. (Report No. UMTRI-95-18). The University of Michigan Transportation Research Institute, Ann Arbor, Michigan. Retrieved from http://www.nascoinc.com/standards/hivis/u%20of%20m%20visibility%20research%20study.pdf
• Wood, J.M., Tyrrell, R.A., & Carberry, T.P. (2003). Pedestrian visibility at night: Effects of Pedestrian Clothing, Driver Age, and Headlamp Beam Setting. 2003 Annual Meeting of the Transportation Research Board, Washington, D.C. Retrieved from http://www.ltrc.lsu.edu/TRB_82/TRB2003-001537.pdf
• Tyrrell, R.A., Brooks, J., Balk, S.A., & Carpenter, T.L. (2006). Pedestrian Conspicuity at Night: How Much Biological Motion is Enough? Transportation Research Board 85th Annual Meeting. Washington D.C. Retrieved from http://trid.trb.org/view.aspx?id=777563
• Kwan I., & Mapstone, J. (2009). The Cochrane Collaboration: Interventions for increasing pedestrian and cyclist visibility for the prevention of death and injuries (Review), The Cochrane Library 2009, Issue 4. Retrieved from http://www.thecochranelibrary.com/userfiles/ccoch/file/Safety_on_the_road/CD003438.pdf
• Graving, J.S., Tyrrell, R.A., Balk, S.A., Mendel, J., Braly, N.M., Sinakhonerath, L., O’Hara, L.H., & Moore, K.S. (2009). The effect of retroreflectivity and biological motion on the visibility of pedestrians at night. Journal of Vision, August 2009, Volume 9, No. 8, Article 625. Retrieved from http://www.journalofvision.org/content/9/8/625
• Wood, J.M., Tyrrell, R.H., Marszalek, R., Lacherez, P., Chaparro, A., & Britt, T.W. (2011). Using biological motion to enhance the conspicuity of roadway workers. Accident Analysis & Prevention. Volume 43, Issue 3, May 2011, Pages 1036-1041. Retrieved from http://www.sciencedirect.com/science/article/pii/S0001457510003799