查看更多>>摘要：The purpose of this study was to determine how pavement markings influence bicyclist and motorist positioning, particularly how far bicyclists travel from parked cars. The research examined the effects of the sequential addition of the component markings of a bicycle lane on a road with on-street parking in Cambridge, Massachusetts. The data measured were the distance that cars parked from the curb, the distance that bicyclists rode from the curb, and the distance that traveling motor vehicles drove from the curb. Data on bicyclists and moving motor vehicles were gathered by videotaping. The three pavement marking treatments—an edge line demarcating the travel lane, the edge line and bicycle symbols, and a full bicycle lane—were all effective at influencing bicyclists to ride farther away from parked cars than when no pavement markings were present. All three treatments significantly increased the percentage of cyclists riding more than 9 and 10 ft from the curb; these distances were used as benchmarks for where cyclists should ride to be farther from the opening-door zone of a parked car. There was variation between the signalized and the uncontrolled intersections. Before-and-after intercept surveys of cyclists and motorists were administered. In the before survey, cyclists most often responded that the best way to improve bicycling on Hampshire Street was to add bicycle lanes. Cyclists also rated the full bicycle lane most favorably in the after survey. There was no change in cyclist comfort levels between the before and the after surveys. When motorists were asked what made them most aware of cyclists on the street; the most common response in the before survey was "nothing." In the after survey, the most common response was "the bicycle lane."
Mary Paul MeletiouJudson J. LawrieThomas J. CookSarah W. O'Brien...
p.15-21页
查看更多>>摘要：The northern Outer Banks coastal area in North Carolina is well suited to drawing bicycle tourism because of its geography, climate, and attractions. In 2003, the North Carolina Department of Transportation commissioned a study to examine the value of public investment in bicycle facilities that have been constructed in this area over the past 10 years at a cost of approximately $6.7 million. A particular challenge in conducting this study was that tourists visited the Outer Banks for a variety of reasons, not just for cycling. Thus, the collection of information on the amount and nature of bicycling activity and on the spending patterns of bicyclists in the area was critical for the development of an economic impact analysis. Researchers surveyed cyclists using the bicycle facilities (shared-use paths and wide paved shoulders) and obtained data from self-administered surveys of tourists at visitor centers during the primary tourist season. The data collected were then used to determine the economic impact of bicycling visitors to the area. Seventeen percent of tourists to the area reported that they bicycled while there; this translates to 680,000 people annually. The economic impact of bicycling visitors is significant: a conservative annual estimate is $60 million, with 1,407 jobs created or supported per year. This is almost nine times greater than the one-time expenditure required to construct the facilities. Continued investment in bicycle facilities is expected to increase this favorable economic impact and is therefore recommended.
查看更多>>摘要：The current state of the practice for traffic signal timing does not account for bicyclists in determining the minimum green times or clearance intervals. Like pedestrians, bicyclists need sufficient time to cross an intersection safely. However, this need must be balanced against possible delays for motorist traffic. Accurate estimates of crossing times for bicyclists are thus essential to the safe and efficient design of traffic signals. This paper presents data on bicycle crossing times for different crossing distances near the campus of the University of California at Davis and provides a methodology for measuring bicycle crossing times that other researchers can use. The crossing time and speed data collected for this project can be used to develop guidelines, in conjunction with AASHTO equations, for estimation of minimum green times and clearance intervals as a function of crossing distance. Ten signalized intersections with various motorist and bicycle traffic volumes were videotaped for a total of approximately 11 h. The observed crossing times and calculated speeds for standing, rolling, and quasi-rolling starts are presented. The importance of the physical design of intersections is briefly discussed. Important findings are that the crossing tunes vary widely for each crossing distance and that the 2nd and 15th per-centile speeds are considerably slower than the speeds suggested by AASHTO. These slower speeds may suggest that longer crossing times should be used in signal design to ensure that 98%, or even 85%, of bicyclists will be able to clear an intersection safely.
Joseph E. HummerNagui RouphailRonald G. HughesShannon J. Fain...
p.28-36页
查看更多>>摘要：Shared-use paths are becoming increasingly busy across the United States. Path designers need guidance on how wide to make new or rebuilt paths and on whether to separate the different types of users. The current guidance is not specific, has not been calibrated to conditions in the United States, and does not accommodate the range of modes found on a typical path. The purpose of this project, sponsored by FHWA, was to develop a level-of-service (LOS) estimation method for shared-use paths that overcomes these limitations. The focus of this paper is on the collection of the perceptions of path users and the development of a model relating those perceptions to operational and path variables. Companion papers describe the efforts made to develop equations explaining path operations and to develop an LOS estimation tool based on the perception model. For this effort, the project team collected the perceptions of 105 volunteers viewing 36 video clips from 10 paths. Analysis showed that variables related to path operations and the path width had the strongest relationships to the overall quality of the trail experience. The recommended model for overall rating included terms for path width, the number of meeting and passing events, and the presence of a center-line. The model was statistically sound; it should be easy to use. Analysts should be able to use the model and the procedure for determination of the LOS, which is based on the model, with confidence, knowing that it is well grounded on the perceptions of a large sample of trail users.
William W. HunterJohn R. FeaganesRaghavan Srinivasan
p.37-44页
查看更多>>摘要：This paper examines the operational effects of converting a 14-ft-wide curb lane to an 11-ft-wide travel lane with a 3-ft-wide undesignated lane at various locations in Broward County, Florida. Six midblock sites with various configurations were selected for study. Two of the midblock sites had previously been striped with the 3-ft undesignated lane, and these served as comparison sites. Videotapes were taken of bicyclists riding through the midblock and intersection locations before and after placement of the 3-ft undesignated lane striping. At the locations where the 3-ft stripe was already in place, the videotaping was done to examine whether changes were occurring over time. Software was used to extract images at all midblock locations so that before and after lateral spacing measurements could be obtained. After the new striping, (a) bicycles were ridden, on average, 7 to 9 in. further away from the gutter pan seam; (b) motor vehicles were driven, on average, 6 to 12 in. farther away from the gutter pan seam; (c) passing motor vehicles were driven, on average, 3 to 5 in. closer to bicycles at curb and gutter sites; conversely, passing motor vehicles were driven, on average, 4 to 5 in. farther away from bicycles at the sites where the stripe was already in place; and (d) the addition of the stripe at new locations had the effect of reducing the amount of motor vehicle encroachment into the adjacent lane on these multilane roadways.
查看更多>>摘要：Simple and reliable tools for estimating and predicting the amount of bicycling in an area would be useful for a variety of investment and policy decisions. Previous efforts to develop such tools have typically tried to develop demand estimates from basic descriptors of the population, land use, and bicycling facilities of an area. This paper takes an alternative approach by using the idea of deriving estimates of the likely range of total bicycling demand in an area on the basis of census commute-to-work data. The paper makes three contributions. The first is a general discussion of the total amount of bicycling in the United States and how it varies across places, on the basis of a number of surveys and some original data analysis. The second is the development of an argument that predictive models based on land use and transportation factors are unlikely to ever be accurate or useful because of a number of intractable problems. Third, a simple model is developed for estimation of a range of current levels of bicycling in a given geographic area with reasonable and known accuracy and by use of easily available data. While this model stops short of predicting bicycling levels or demand on specific facilities, it is an important first step in reaching these objectives. There is such a high degree of local variation in bicycling rates in the United States that attempts to predict bicycling levels directly without accounting for current levels are unlikely to be consistently successful.
Theodore A. PetritschBruce W. LandisPeyton S. McLeodHerman F. Huang...
p.55-62页
查看更多>>摘要：This paper documents a study performed to develop a level-of-service (LOS) model that accurately represents pedestrians' perceptions of crossings at signalized intersections. This model incorporates perceived safety and comfort (i.e., perceived exposure and conflicts) and operations (i.e., delay and signalization). Data for the model were obtained from an innovative Walk for Science field data collection event and video simulations. The data consist of (a) participants' perceptions of safety, comfort, and operations as they walk through selected signalized intersections and (b) the design and operational characteristics of these intersections. The resulting model provides a measure of the pedestrian's perspective on how well an intersection's geometric and operational characteristics meets his or her needs. The pedestrian LOS model for intersections described in this paper is based on Pearson correlation analyses and stepwise regression modeling of approximately 800 combined real-time perceptions (observations) from pedestrians walking a course through signalized intersections in a typical U.S. metropolitan area. The resulting general model for the pedestrian LOS at intersections is highly reliable, has a high correlation coefficient (R~2 = .73) with the average observations, and is transferable to the majority of metropolitan areas in the United States. Primary factors in the pedestrian LOS model for intersections include right-turn-on-red volumes for the street being crossed, permissive left turns from the street parallel to the crosswalk, motor vehicle volume on the street being crossed, midblock 85th percentile speed of the vehicles on the street being crossed, number of lanes being crossed, pedestrian's delay, and presence or absence of right-turn channelization islands.
查看更多>>摘要：Recent advances in pedestrian push-button design, led by the development of accessible pedestrian signals (APSs), have created a new method of communicating traffic control information to pedestrians. Some APS devices have beaconing features or verbal (speech) message capabilities obtained by pressing and holding the pedestrian push button for approximately 3 s. Other features, such as the extension of the walk interval, may also be activated with an extended press of the push button. Recent research has suggested that 3 s may be excessive because it is hard for some users to hold the push button for this long. Additionally, most pedestrians may not hold the push button for this length of time. The problem lies in determining how long the APS push button should be pressed for a push-button information message or special accessibility features to be obtained. The primary objective of the research described in this paper was to develop a time distribution of typical pedestrian push-button activation durations. Data were obtained by attaching a voltage recorder to the pedestrian push-button circuit inside traffic signal controllers at eight locations in three cities in Wisconsin and Massachusetts. This device recorded the amount of time, to the nearest 1/100 of a second, that each pedestrian push button was pressed. A total of 1,439 push-button presses were recorded. The average push-button press duration was 0.2 s. More than 95% of all push-button presses recorded were less than 1.0 s. Only four push-button presses exceeded 3.0 s. The results show that the duration of an extended push-button press needed to obtain additional crossing information can be reduced to approximately 1 s without a significant number of false calls. A 1-s press will minimize the effort required for pedestrians to actuate special accessible features, while it will minimize unnecessary noise and vehicular traffic disruption.
Alan C. ScottLinda MyersJanet M. BarlowBillie Louise Bentzen...
p.69-76页
查看更多>>摘要：Push-button-integrated accessible pedestrian signals (APSs) provide audible information from the push-button housing on both the location of the push button and the onset of walk intervals. APS systems must provide clear, unambiguous information on which crosswalk has the walk interval. Push buttons in the United States, including push-button-integrated APSs, are inconsistently located, and APSs do not use consistent sounds to convey the "Walk" indication. The present research (NCHRP Project 3-62) investigated the effects of push-button placement and the type of audible "Walk" indication on visually or cognitively impaired participants' ability to determine which of two streets had the "Walk" signal. Participants performed this task most quickly and most accurately when each push-button-integrated APS was mounted on its own pole, the poles were placed along the outer line (farthest from the center of the intersection) of the associated crosswalk, each pole was located within a few feet of the curb, and the audible "Walk" indication from each APS was a fast tick (percussive sound) at 10 repetitions per second. The results further indicate that where two push buttons are installed on a single pole, verbal "Walk" messages (e.g., "Seventh; walk sign is on to cross Seventh") result in greater accuracy than two different sounds (fast tick and cuckoo) to signal the two crossings.
Robert J. SchneiderRobert S. PattenJennifer L. Toole
p.77-90页
查看更多>>摘要：Federal funding for pedestrian and bicycle transportation has increased over the past 15 years, with a resulting increase in shared-use pathways, paved shoulders, bicycle lanes, and sidewalks in many parts of the United States. This has caused communities to ask questions: Where is pedestrian and bicycle activity taking place? What effect does facility construction have on levels of bicycling and walking? What are the characteristics of nonmotorized transportation users? How many miles of pedestrian and bicycle facilities are available? Where are existing facilities located? This paper provides a summary of recent research that was sponsored by FHWA and the Pedestrian and Bicycle Information Center to review and evaluate bicycle and pedestrian data collection methods throughout the United States. It uses a case study approach to evaluate pedestrian and bicycle data collection in 29 different agencies throughout the country in communities ranging in size from 6,000 residents (Sandpoint, Idaho) to 8 million residents (New York City). These case studies are analyzed in the following data collection categories: manual counts, automated counts, surveys targeting nonmotorized transportation users, surveys sampling a general population, inventories, and spatial analyses. The results provide information about the methods and the optimum timing for pedestrian and bicycle data collection; emerging technologies that can be used to gather and analyze data; the benefits, limitations, and costs of different data collection techniques; and implications for a national data collection strategy.
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