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1.
This paper presents the results of an observation study of interactions between bicyclists and buses on shared bus lanes. The aim of the paper is to analyse bicyclists’ safety on bus lanes shared with bicyclists. Straight sections of two bus lanes shared with bicyclists in Belgium are observed. All interactions between bicyclists and buses over two full weeks are recorded and analysed. Additionally, the lateral position and riding speed of bicyclists that are in interaction with buses are compared with the behaviour of bicyclists that are not in interaction with buses. One of the observed bus lanes is in line with road design guidelines in a number of countries that state that a sufficiently narrow bus lane (<3.5 m) is hypothesised to be safer than a somewhat wider bus lane; the other observed bus lane is deemed too wide according to these guidelines and is hypothesised to lead to close overtaking manoeuvres.The results show that close interactions between bicyclists and buses are relatively frequent on both types of analysed bus lanes. Close overtaking manoeuvres (a bus overtakes a bicyclist with a lateral distance less than 1 m) as well as close bicycle-following situations (a bus drives behind a bicyclist with a time gap less than 2 s) are quite common on both analysed bus lanes. The analyses could not confirm the hypothesis that a sufficiently narrow bus lane is safer than a wider bus lane. On the contrary, close interactions seem even slightly more common on the narrower bus lane. Slightly more close overtaking manoeuvres take place on the narrower bus lane, but the difference is not statistically significant. Additionally, more bicycle-following situations take place on the narrower bus lane because overtaking is more difficult. The results show that buses often maintain a close time gap in these situations. The overtaking speed of the buses is, however, significantly higher on the wider bus lane compared to the narrower one.Moreover, the presence of a bus has an influence on the behaviour of bicyclists. Bicyclists who get overtaken by a bus ride more closely to the edge of the road than bicyclists who are not in interaction with a bus. While the road design guidelines assume that bicyclists take up a width of one meter from the edge on bus lanes shared with bicyclists, the observations show that bicyclists take up much less space while being overtaken. The presence of a bus does not have a significant influence on the standard deviation of the lateral position of the bicyclist. On the narrower bus lane, some findings suggest that bicyclists who are involved in an interaction with a bus ride faster than bicyclists who are not involved in an interaction with a bus.  相似文献   

2.
A safe headway to the lead vehicle is important to reduce conflicts with merging vehicles from highway on-ramps. Previous research has outlined the advantage of gap metering strategies to yield sufficient space to merging vehicles and improve highway capacity during peak hours. However, prevailing gap metering systems fail to indicate the minimum required gap and leave it to the drivers’ judgment to adjust their headway. This paper proposes a new Active Gap Metering (AGM) signalization that helps outer lane drivers to adjust their headway to the lead vehicle when approaching highway ramps with incoming vehicles. This AGM signalization represents a combination of pavement markings and an innovative Variable Message Sign (VMS). The AGM system was tested alone and in combination with additional variable speed limits (VSL) in distinct environments of the Doha Expressway in the State of Qatar using a driving simulator. The driving behavior of 64 drivers was analyzed using repeated-measures ANOVA. The results showed that the AGM effectively influenced the drivers’ behavior on the right stream lane. Drivers did gradually increase the distance to the lead vehicle, which resulted in optimal headways to merging on-ramp vehicles. Most importantly, the minimum time-to-collision (TTCmin) to the merging vehicle was increased by an additional 1–1.5 s as compared to no treatment. The proposed AGM signalization can, therefore, be considered by policymakers to influence drivers’ headways at critical merging sections.  相似文献   

3.
Presently, the collection and analysis of naturalistic data is the most credited method for understanding road user behavior and improving traffic safety. Such methodology was developed for motorized vehicles, such as cars and trucks, and is still largely applied to those vehicles. However, a reasonable question is whether bicycle safety can also benefit from the naturalistic methodology, once collection and analyses are properly ported from motorized vehicles to bicycles. This paper answers this question by showing that instrumented bicycles can also collect analogous naturalistic data. In addition, this paper shows how naturalistic cycling data from 16 bicyclists can be used to estimate risk while cycling. The results show that cycling near an intersection increased the risk of experiencing a critical event by four times, and by twelve times when the intersection presented some form of visual occlusion (e.g., buildings and hedges). Poor maintenance of the road increased the risk tenfold. Furthermore, the risk of experiencing a critical event was twice as large when at least one pedestrian or another bicyclist crossed the bicyclist’s trajectory. Finally, this study suggests the two most common scenarios for bicycle accidents, which result from different situations and thus require different countermeasures. The findings presented in this paper show that bicycle safety can benefit from the naturalistic methodology, which provides data able to guide development and evaluation of (intelligent) countermeasures to increase cycling safety.  相似文献   

4.
Advancements in technology are bringing automated vehicles (AVs) closer to wider deployment. However, in the early phases of their deployment, AVs will coexist and frequently interact with human-driven vehicles (HDVs). These interactions might lead to changes in the driving behavior of HDVs. A field test was conducted in the Netherlands with 18 participants focusing on gap acceptance, car-following, and overtaking behaviors to understand such behavioral adaptations. The participants were asked to drive their vehicles in a controlled environment, interacting with an HDV and a Wizard of Oz AV. The effects of positive and negative information regarding AV behavior on the participants’ driving behavior and their trust in AVs were also studied. The results show that human drivers adopted significantly smaller critical gaps when interacting with the approaching AV as compared to when interacting with the approaching HDV. Drivers also maintained a significantly shorter headway after overtaking the AV in comparison to overtaking the HDV. Positive information about the behavior of the AV led to closer interactions in comparison to HDVs. Additionally, drivers showed higher trust in the interacting AV when they were provided with positive information regarding the AV in comparison to scenarios where no information was provided. These findings suggest the potential exploitation of AV technology by HDV drivers.  相似文献   

5.
Research in cycling safety seeks to better understand bicycle-related crashes and injuries. The present naturalistic cycling study contributes to this research by collecting data about bicyclists’ behavior and impressions of safety–critical situations, information unavailable in traditional data sources (e.g., accident databases, observational studies). Naturalistic data were collected from 16 bicyclists (8 female; M = 39.1 years, SD = 11.4 years) who rode instrumented bicycles for two weeks. Bicyclists were instructed to report all episodes in which they felt uncomfortable while riding (subjective risk perception), even if they didn’t fall. After data collection, the bicyclists were interviewed in detail regarding their self-reported safety–critical events. Environmental conditions were also recorded via video (e.g., road surface, weather). In total, 63 safety–critical events (56 non-crashes, 7 crashes) were reported by the bicyclists, mainly due to interactions with other road users – but also due to poorly maintained infrastructure. In low-visibility conditions, vehicle-bicycle and bicycle-bicycle events were the most uncomfortable for the bicyclists. Self-reported pedestrian–bicycle events primarily consisted of pedestrians starting to cross the bicycle path without looking. With one exception, all crashes found in the study belonged to poorly maintained road and infrastructure. In particular, construction work or obstacles in the bicycle path were reported as uncomfortable and annoying by the bicyclists. This study shows how naturalistic data and bicyclists’ interviews together can provide a more informative picture of safety–critical situations experienced by the bicyclist than traditional data sources can.  相似文献   

6.
In Europe, the use of electric bicycles is rapidly increasing. This trend raises important safety concerns: Is their use compatible with existing infrastructure and regulations? Do they present novel safety issues? How do they impact other traffic? This study sought to address these concerns, using instrumented electric bicycles to monitor e-cyclists’ behavior in a naturalistic fashion. Data was collected from 12 bicyclists, each of whom rode an instrumented bicycle for two weeks. In total, 1500 km worth of data were collected, including 88 critical events (crashes and near-crashes). Analysis of these critical events identified pedestrians, light vehicles and other bicycles as main threats to a safe ride. Other factors also contributed to crash causation, such as being in proximity to a crossing or encountering a vehicle parked in the bicycle lane. A comparison between electric and traditional bicycles was enabled by the availability of data from a previous study a year earlier, which collected naturalistic cycling data from traditional bicycles using the same instrumentation as in this study. Electric bicycles were found to be ridden faster, on average, than traditional bicycles, in addition to interacting differently with other road users. The results presented in this study also suggest that countermeasures to bicycle crashes should be different for electric and traditional bicycles. Finally, increasing electric bicycle conspicuity appears to be the easiest, most obvious way to increase their safety.  相似文献   

7.
In recent years, more use of narrow lanes as a temporary traffic management scheme (TTMS) on UK motorway roadwork sections has been made. The rationale is to free up carriageway space, especially for sites with high traffic demands needing repairs. What remains to be determined is the impact of this work on traffic operation. This is important due to the need to manage traffic operational turbulence which could affect the capacity as well as safety levels in roadwork sections. Site observations (mainly using camcorders from overhead bridges) were made which uncovered two discernible patterns of driving behaviour where narrow lanes are implemented at roadworks, especially when heavy goods vehicles (HGVs) are present: (i) “avoiding” passing/overtaking HGVs travelling in the adjacent lanes and (ii) lane “repositioning” while passing/overtaking which might cause some turbulence to traffic operation. From one site, almost half of the passenger car drivers (including small vans) who were following a HGV on the adjacent lanes were avoiding passing that HGV. Also, nearly three quarters of the observed passenger cars, the passenger car drivers tried to position their vehicles as far away as possible, laterally, from the adjacent HGV while passing/overtaking that HGV in order to widen the lateral gap between their vehicles and the HGV. This resulted in driving too close to the edge of the road markings of their current lane away from the HGV. Therefore, this paper aims to report on the “avoiding” and lane “repositioning” behaviours to help inform traffic management teams/designers using narrow lanes as TTMS and make them aware of such behaviours (especially for motorway sections carrying high percentages of HGVs). Also, the finding from these observations were used in the development of a new micro-simulation model in order to evaluate the effect of such turbulence.  相似文献   

8.
The Geller typology, which categorizes the population into four types of bicyclists (strong and fearless, enthused and confident, interested but concerned, and no way no how) has gained considerable popularity amongst researchers and planners. One large U.S. study used a survey-derived approach to categorize respondents into Geller’s typology, and found the majority of Americans were “interested but concerned”. While the U.S. findings are widely cited in planning documents, there has yet to be an assessment as to whether this indirect survey-derived categorization into Geller’s typology corresponds with how bicyclists perceive themselves. Using a mixed methods approach, we explored the Geller typology from the view of bicyclists themselves. Our specific objectives were to assess whether the survey-derived categorization method aligned with bicyclists’ perceptions, and to also examine bicyclists’ interpretations of Geller’s typology. We conducted a cross-sectional survey of bicyclists (n = 281) and interviews with a subset of participants (n = 25). According to the survey-derived categorization, the distribution of the sample (n = 25) was: 4% strong and fearless, 12% enthused and confident, and 84% interested but concerned. In the interviews we learned there was only a match between survey-derived and self-perceived bicyclist type for seven of twenty-five (28%) participants. When asked, participants were more likely to categorize themselves to strong and fearless (24% overall) or enthused and confident (52% overall). Our findings suggest that the category titles are intuitive, however, the survey-derived categorization does not necessarily match with how bicyclists perceive themselves. This suggests that, at least for those who currently bicycle, a direct approach of asking people which type of bicyclist they identify with may be preferable.  相似文献   

9.
Cars overtaking cyclists have been identified as a source of crashes and subjective risk. Several studies investigated the passing distance for different road types. There has been less research concerning cyclists’ expectations concerning the passing distance at different road types. Thus, we aim at contrasting cyclists’ expectations about the passing safety for different speed limits and cycling infrastructures with the passing distances observed at corresponding urban road types. For this purpose, we show participants images of a predefined set of survey zones in a web-based survey, and ask them about the expected passing safety of cars overtaking them when imagining riding their bikes at these locations. We measure the observed passing distances at the same survey zones with a bike-mounted sensor. We find that cars meet the German legal minimum passing distance of 1.5 m in towns in only 30% of all observed events. In 30 km/h speed zones, passing distances at roads featuring dedicated cycling infrastructure (e.g. bike lanes, cycling boulevards) are decreased as compared to those featuring no cycling infrastructure. In contrast, people estimate that the passing safety on roads with dedicated cycling infrastructure is safer than without cycling infrastructure. This effect is even more pronounced on living streets. Situations where oncoming cars (e.g. living streets, ‘opposite’ roads) must be passed in close distance are apparently not perceived as particularly dangerous. Cycling tracks in 50 km/h speed zones increase both the observed passing distance and the corresponding expectations about passing safety. Taken together, the qualitative comparison of the two datasets implies that cyclists’ expectations about cars passing them in a more adequate and safe distance in streets with reduced speed limits and dedicated cycling infrastructure are not justified in light of the actually observed passing distances. Possible explanations for the contradicting patterns could be that cyclists prefer situations where space is explicitly dedicated for bikes, that they account for the anticipated car traffic volume, and that they assume oncoming cars as less dangerous to pass.  相似文献   

10.
Correctly designed roundabouts proved to have positive safety and functional performances. However, they are also affected by peculiar disadvantages. In particular, they are difficult to manoeuvre, especially for heavy vehicle drivers. Despite these concerns, there are currently no driving workload metrics devoted to roundabouts.A novel methodological approach is proposed for trying to quantify workload impinging on heavy vehicle drivers when manoeuvring through complex at-grade intersections. Proper acquisition of input data constitutes the starting point for future research about ascertainment of workload for these particular road scenarios. The described procedure enables recording steering wheel angles performed by a driver when manoeuvring an articulated lorry through a complex at-grade intersection. A field trial was carried out for verifying the practical feasibility of proposed method in capturing driver’s steering behaviour. Dynamic data acquired via global navigation satellite system instrumentation were related to actual driver’s steering wheel behaviour captured by camera frames. As a complement to the experiment, selected steering behaviour metrics were calculated. Steering Entropy attributed a high difficulty level to the manoeuvres performed through the roundabout, whereas High Frequency Component and Steering Reversal Rate showed intensity and occurrences of driver’s corrections needed for controlling position of the semitrailer at the ring. It appears that even a single roundabout may represent an arduous task for drivers. The study concludes with recommendations for further research about workload imposed by roundabouts to heavy vehicle drivers, with special attention to successions of closely spaced roundabouts.  相似文献   

11.
IntroductionThe lateral clearance distance of a motorized vehicle while overtaking a cyclist is a key indicator of safety. This lateral clearance distance has never been measured for cyclists transporting a child. Therefore the aim of this study was to investigate the behaviour of motorized vehicles in overtaking cyclists with and without a child on the same bicycle.MethodsThe lateral clearance distance of the overtaking manoeuvres of motorized vehicles was measured using an instrumented bicycle when performing 19 cycling trips on one single road with two different types of cycling infrastructure (a bike lane and shared lane marking) in the Brussels Capital Region (Belgium). Mixed effect regression was used to examine the effect of cycling condition (cyclist without a child [control], cyclist with a child bike seat and cyclist with a child bike trailer) and secondary independent variables (i.e. cycling infrastructure, peak traffic hours and traffic density) on the lateral clearance distance.ResultsThe mean lateral clearance distance in ‘cyclists without child’ was significantly smaller (117.3 cm) than in ‘cyclists with child’ (128.8 cm) (95%CI [7.2;15.9]). Looking at ‘morning peak traffic hours’ (i.e. 7:00 to 9:00 a.m.) a cyclist with child bike seat was overtaken at greater lateral clearance distances than a cyclist with a child bike trailer or a cyclist without child (p=0.041). Furthermore, the percentage of passing manoeuvres under 100 cm was significantly higher in ‘cyclist without child’ (35.3%) in comparison to ‘cyclist with child bike seat’ (21.8%) and ‘cyclist with child bike trailer’ (21.8%) (Chi2=29.19, p<0.001). No significant differences were found between a shared lane marking and bike lane.ConclusionDrivers of motorized vehicles do adapt their overtaking manoeuvre when they overtake cyclists transporting a child, keeping greater and therefore safer lateral clearance distances. In morning peak traffic hours and/or crowded circumstances the child bike seat can be considered as the safest way to transport a child in terms of lateral clearance distance. In general, with 25.3% overtaking manoeuvres under 100cm, police should monitor compliance with the traffic rules with regard to cyclists, and motorists should be more aware of the overtaking traffic rules.  相似文献   

12.
The research explored the relative merits of several forms of overtaking lane delineation and signage treatments in the safe and controlled environment of a simulated driving task. The experiment compared the effects of three lane marking and signage treatments across six different overtaking sites. At sites where forward visibility was restricted due to the topography or road geometry, there were pronounced differences in drivers’ lane position, speed, and the number of vehicles overtaken. The presence of a continuity line used in the diverge portion of two of the treatments was successful in moving more drivers to the left (slow) lane. A continuity line at the end of the merge portion of one treatment delayed drivers’ merging and was associated with shorter headway distances.  相似文献   

13.
An experiment tracked drivers’ gaze patterns as they made judgements about the manoeuvring intentions of a bicyclist at a T-junction. The stimuli involved a factorial manipulation of the bicyclist’s arm-signals and gaze cues, as well as whether the participant viewed the bicyclist from the major road or the minor road. When making their decisions, there was a strong tendency for participants to direct their gaze, and so presumably their attention, to the bicyclist’s face before any other relevant area, including the arm when it was used for signalling. Moreover, participants not only spent longer looking at the face than any of the other aspects of the bicyclist that were considered, but this effect was particularly pronounced in situations where the bicyclist was effectively making eye-contact with the participant. These findings support the idea that encountering a bicyclist is a fundamentally social interaction and suggest that drivers exhibit an attentional bias, such that they are particularly likely to seek out the face upon seeing a vulnerable road user. In light of the substantial literature on reflexive processing that seems to occur when faces are viewed, this bias may help explain slow driver decision responses to bicyclists seen in previous studies.  相似文献   

14.
15.
The current research set out to measure the moderating effect that urban design may have on bicyclist physiology while in transition. Focusing on the hilly City of Wuppertal, Germany, we harnessed bicyclists with mobile sensors to measure their responses to urban design metrics obtained from space syntax, while also adjusting for known traffic, terrain, and contextual factors. The empirical strategy consisted of exploratory data analysis (EDA), ordinary least squares (OLS), and a local regression model to account for spatial autocorrelation. The latter model was robust (R2 = 68%), and showed that two statistically significant (p < 0.05) urban design factors influenced bicyclist physiology. Controllability, a measure of how spatially dominated a space is, increased bicyclist responses (i.e., decreased comfortability); while integration, which is related to accessibility and connectivity, had the opposite effect. Other noteworthy covariates included one-way streets and density of parked automobiles: these exerted a negative influence on bicyclist physiology. The results of this research ultimately showed that nuanced urban designs have a moderate influence on bicycling comfort. These outcomes could be utilized by practitioners focused on implementing appropriate interventions to increase bicyclist comfort levels and this mode share.  相似文献   

16.
The preference to maintain a certain desired speed is perhaps the most prevalent explanation for why a driver of a manually driven car decides to overtake a lead vehicle. Still, the motivation for overtaking is also affected by other factors such as aggressiveness, competitiveness, or sensation-seeking caused by following another vehicle. Whether such motivational factors for overtaking play a role in partially automated driving is yet to be determined. This study had three goals: (i) to investigate whether and how a driver's tendency to overtake a lead vehicle changes when driving a vehicle equipped with an adaptive cruise control (ACC) system. (ii) To study how such tendencies change when the headway time configuration of the ACC system varies. (iii) To examine how the manipulation of the speed and speed variance of the lead vehicle affect drivers' tendencies to overtake a lead vehicle. We conducted two different experiments, where the second experiment followed the first experiment's results. In each experiment, participants drove three 10–12 min simulated drives under light traffic conditions in a driving simulator under manual and level one (L1) automation driving conditions. The automation condition included an ACC with two headway time configurations. In the first experiment, it was 1 sec and 3 secs, and in the second, it was 1 sec and 2 secs. Each drive included six passing opportunities representing three different speeds of the lead vehicle (−3 km/h, +3 km/h, +6 km/h relative to the participant), with or without speed variance. Results show that drivers tended to overtake a lead vehicle more often in manual mode than in automated driving modes. In the first experiment, ACC with a headway time of 1 sec led to more overtaking events than ACC with 3 secs headway time. In addition, the relative speed of the lead vehicle and its speed variability affected overtaking tendencies. In the second experiment, the relative speed of the lead vehicle and its speed variability affected overtaking tendencies only when interacting with each other and with driving configuration. When the speed of the lead vehicle was +3 km/h and included variability, more overtaking events occurred in manual mode than both automation modes. This work has shown that driving with ACC might help reduce overtaking frequencies and more considerable when the headway time is set to 3 secs.  相似文献   

17.
In a recent study, Vansteenkiste et al. (2014) described how low quality bicycle paths cause an apparent shift of visual attention from distant environmental regions to more proximate road properties. Surprisingly, this shift of visual attention was not accompanied by an adaptation in cycling speed. The current experiment investigated to what extent these findings are applicable for young learner bicyclists (aged 6–12 years). Since young learner bicyclists do not yet have mature visual and motor skills, it was expected that the implications of a poor road surface would be larger for them than for experienced adult bicyclists. In general, children looked less to the road and more to task irrelevant regions, but the magnitude of the shift of visual attention when cycling on a low quality bicycle track was similar to that of adults. Although children cycled slower than adults, they did not cycle slower on the low quality track compared to the high quality track. Overall, our results suggest that children displayed a different visual-motor strategy than adults, characterized by lower cycling speeds and a different visual behaviour, and that they responded in a similar way to a low quality bicycle path as adults.  相似文献   

18.
Understanding how road environments stress bicyclists (and prospective bicyclists) has important implications for road design and network planning. With the rise of wearable bio-sensing technology, the potential for measuring real-time environmental acute stress is emerging. In this naturalistic cross-over field experiment, we investigate bicyclist stress through heart rate variability (HRV). We examine the relationship between HRV and the road environment through a series of multilevel statistical models. Results suggest that participants’ HRV are only certain to differ on one (the local road) of five road environments tested. The differences in participants’ HRV between two collectors and two arterials are far more tenuous. We discuss the validity of HRV and other biometrics for assessing stress and discuss how HRV and other biometrics might help improve our understanding of bicyclists’ perceptions of road environments.  相似文献   

19.
An important factor in single-sided accidents of older cyclists is that they ride off the cycle path onto the verge. Two experiments were performed to assess the feasibility of using virtual 3D objects in the verge to affect the lateral position of bicyclists. In the first experiment, different virtual objects were placed in the shoulder and 1150 passing bicyclists were observed using a fixed camera. The (standard deviation of the) lateral position and speed in four conditions with virtual objects differing in colour, structure, or 3D effect were compared with a control condition in which no virtual objects were applied. In a second experiment, the behaviour of 32 bicyclists aged 50 years or older was measured by mounting two digital action cameras with GPS on the participants’ bicycles. The participants cycled a route of approximately 12 km in which several locations were passed, one of these contained 15 virtual objects similar to the ones used in the first experiment placed in the shoulder of the cycle path. Cyclist behaviour was compared with behaviour at a control location consisting of a solitary two-way cycle path with a grass shoulder. Results indicate that the virtual objects in the tested format had little overall effect on cyclists’ behaviour. However, bicyclists were positioned closer to the virtual objects and the shoulder when they looked at the objects or when they reported that they saw them while cycling. This suggests that the overall visibility of the object design may have been too conservative.  相似文献   

20.
As cities make concerted efforts to become more bicycle-friendly through policy changes and infrastructure, it is important that such efforts ultimately support people who currently bicycle and remove barriers that may prevent more people from bicycling. Travel surveys can reveal the nature and distribution of bicycling trips, but perceptions and behaviours of bicyclists are better understood through qualitative methods. In particular, developing cycling cities are unique settings to examine how the built environment supports bicycling as changes are made to increase bicycling levels. Through semi-structured interviews, this research explores the case of Hamilton, Ontario and the factors that influence route choice from the perspective of regular bicyclists. Major themes were identified using thematic analysis: (i) exclusion from road space; (ii) infrastructure; and (iii) streetscape. Bicyclists highly value infrastructure and seek routes that minimize interactions with cars, while avoiding many arterial roads that prioritize motorists. Routes that appear to be more human-oriented or that have nature are also attractive. Many regular bicyclists report that current bicycle infrastructure does not meet their preferences. Despite building nearly half of the planned infrastructure network, our findings suggest the built environment is not perceived to be oriented to bicycling. This study provides policy and practice recommendations for developing cycling cities in North America as they transition towards established cycling cities.  相似文献   

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