While a variety of labels appear in the literature, the overriding goal of these works is to determine and
predict conditions for safe bicycling based on different cyclists perceptions of safety. The culmination of
these works can best be described under the banner of Level of Service models, originally developed in
1987 in Davis, California and level of service (LOS) models (Epperson 1994; Landis, Vattikuti et al.
1997). The participants of this study were of diverse demographic and skill backgrounds and cycled 30
roadway segments. Including the variables of traffic volume per lane, posted speed limit weighted with
the percentage of heavy vehicles, adjoining land use, width of outside through lane, and pavement
conditions, the researchers were able to explain almost 75% of the variation. The model consists of four basic factors—pavement conditions, traffic speed, lane width, and traffic volume per lane which aim to
serve as a tool for predicting accident along roadways between automobiles and bicycles.
The bulk of the existing literature on bicycle level of service and perceived safety focuses primarily on
through mid-block roadway segments. It rarely separates bicycle lanes from other shared use conditions
(wide curb lanes or paved shoulders) and rarely considers the role of intersections. While stretches of
roadways are important, often the most significant and complex design and safety challenges occur at
street intersections (Jackson 2002). In response to this void, two recent research papers have aimed to
shed light on this matter (Landis 2003; Krizek and Roland 2004). Landis’ recent work (2003) derived a
model to evaluate the perceived hazard of bicyclists riding through intersections. Again, with a highly
varied demographic and cyclist ability sample, this study produced a model with a high degree of
explanatory power (R
2
=0.83) for bicycle intersection level of service. Significant variables included
motor vehicle volume, width of the outside lane, and the crossing distance of the intersection. In this
study there was no control for the presence or absence of a bicycle lane, but the width of the outside lane
variable did include the bicycle lane were it present. The research by Krizek and Roland (2004) analyzed
the severity of instances where existing bicycle lanes and the corresponding physical characteristics.
Using multi-variate analysis, the findings suggest that bicycle lane discontinuities ending on the left side
of the street, with increased distance of crossing intersections, having parking after the discontinuity, and
wider width of the curb lane are statistically elements that contribute to higher levels of discomfort for the
cyclist.
The degree to which perception of safety translates into actual increased safety, however, is still debated.
It proves difficult to translate perceived measures of safety into quantifiable or economic estimates. We
therefore turn to discussing research showing correlations between bicycle facilities and accidents which
yields far from a clear picture.
There is evidence to support the notion that collision-type accidents are lower on off-road paths
(Aultman-Hall and Kaltenecker 1999). Using before and after analysis, Garder’s research (1998) found
raised bicycle crossings to be more appealing and safer for cyclists than at-grade crossings. However,
there exists an equal, if not greater body of research suggesting no relationships or relationships in the
opposite direction. Research examining conflicts at approaching intersections on bike lane and wide curb
lane segments determined that both facilities improve riding conditions for bicyclists, but that the two
facilities themselves are not different in safety (Hunter, Stewart et al. 1999). Smith and Walsh analyzed
before and after accident data for two bike lanes in Madison, Wisconsin finding no statistically significant
difference (Smith and Walsh 1988). Also, Hunter’s analyses of bike-boxes in Eugene, Oregon (Hunter
2000) and blue bike lanes in Portland, Oregon (Hunter, Harkey et al. 2000) demonstrate that no bike-car
conflicts took place while the boxes were used as intended, but that the bike boxes did not seem to
improve the number of conflicts in general (Hunter 2000).
There appears to be good reason for the existing debate over the safety benefits of bicycle facilities. While
there is considerable literature suggesting cyclists perceive greater safety with facilities—and advocates
certainly argue for such—the bottom line is that there little conclusive evidence to suggest such. For this
reason, it is extremely difficult to prescribe guidelines, though, the research methodologies certainly exist
as described above.
ในขณะที่ความหลากหลายของป้ายชื่อปรากฏในวรรณคดี เป้าหมายทำเลที่เหมาะสมของงานเหล่านี้คือการ กำหนด และทำนายสำหรับปั่นจักรยานปลอดภัยอิงนักปั่นต่างรับรู้ความปลอดภัย สุดยอดของผลงานเหล่านี้สามารถอธิบายได้ภายใต้แบนเนอร์ของรุ่นระดับการบริการ พัฒนาในที่สุด ปี 1987 ในเดวิส แคลิฟอร์เนียและระดับของบริการ (LOS) โมเดล (Epperson 1994 แลนดิส Vattikuti et al1997) . ผู้เข้าร่วมการศึกษานี้ได้มีภูมิหลังทางประชากรศาสตร์และทักษะ และขี่จักรยาน 30ส่วนถนน รวมทั้งตัวแปรปริมาณต่อเลน โพสต์จำกัดความเร็วเฉลี่ยกับใช้เปอร์เซ็นต์ของรถถังหนัก สวน ความกว้างของภายนอกผ่านเลน และทางเท้าเงื่อนไข นักวิจัยได้อธิบายเกือบ 75% ของการเปลี่ยนแปลง แบบจำลองประกอบด้วยปัจจัยสี่พื้นฐาน — สภาพถนน ความเร็วการจราจร ความกว้างเลน และปริมาณจราจรต่อเลนซึ่งจุดมุ่งหมายเพื่อทำหน้าที่เป็นเครื่องมือทำนายอุบัติเหตุทางถนนระหว่างรถยนต์และจักรยาน จำนวนมากของวรรณคดีที่มีอยู่บนจักรยานระดับของบริการและความปลอดภัยรับรู้เน้นเป็นหลักในผ่านส่วนบล็อกกลางถนน มันไม่ค่อยแยกจักรยานจากเงื่อนไขอื่น ๆ ที่ใช้ร่วมกัน(เลนกว้างขอบทางหรือไหล่ลาดยาง) และพิจารณาบทบาทของแยกไม่ค่อย ในขณะเหยียดถนนมีความสำคัญ ใหญ่การออกแบบที่ซับซ้อน และสำคัญมากที่สุดและความปลอดภัยความท้าทายเกิดขึ้นในstreet intersections (Jackson 2002). In response to this void, two recent research papers have aimed toshed light on this matter (Landis 2003; Krizek and Roland 2004). Landis’ recent work (2003) derived amodel to evaluate the perceived hazard of bicyclists riding through intersections. Again, with a highlyvaried demographic and cyclist ability sample, this study produced a model with a high degree ofexplanatory power (R2=0.83) for bicycle intersection level of service. Significant variables includedmotor vehicle volume, width of the outside lane, and the crossing distance of the intersection. In thisstudy there was no control for the presence or absence of a bicycle lane, but the width of the outside lanevariable did include the bicycle lane were it present. The research by Krizek and Roland (2004) analyzedthe severity of instances where existing bicycle lanes and the corresponding physical characteristics.Using multi-variate analysis, the findings suggest that bicycle lane discontinuities ending on the left sideof the street, with increased distance of crossing intersections, having parking after the discontinuity, andwider width of the curb lane are statistically elements that contribute to higher levels of discomfort for thecyclist.The degree to which perception of safety translates into actual increased safety, however, is still debated.It proves difficult to translate perceived measures of safety into quantifiable or economic estimates. Wetherefore turn to discussing research showing correlations between bicycle facilities and accidents whichyields far from a clear picture.There is evidence to support the notion that collision-type accidents are lower on off-road paths(Aultman-Hall and Kaltenecker 1999). Using before and after analysis, Garder’s research (1998) foundraised bicycle crossings to be more appealing and safer for cyclists than at-grade crossings. However,there exists an equal, if not greater body of research suggesting no relationships or relationships in theopposite direction. Research examining conflicts at approaching intersections on bike lane and wide curblane segments determined that both facilities improve riding conditions for bicyclists, but that the twofacilities themselves are not different in safety (Hunter, Stewart et al. 1999). Smith and Walsh analyzedbefore and after accident data for two bike lanes in Madison, Wisconsin finding no statistically significantdifference (Smith and Walsh 1988). Also, Hunter’s analyses of bike-boxes in Eugene, Oregon (Hunter2000) and blue bike lanes in Portland, Oregon (Hunter, Harkey et al. 2000) demonstrate that no bike-carconflicts took place while the boxes were used as intended, but that the bike boxes did not seem to improve the number of conflicts in general (Hunter 2000). There appears to be good reason for the existing debate over the safety benefits of bicycle facilities. Whilethere is considerable literature suggesting cyclists perceive greater safety with facilities—and advocatescertainly argue for such—the bottom line is that there little conclusive evidence to suggest such. For thisreason, it is extremely difficult to prescribe guidelines, though, the research methodologies certainly existas described above.
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