Design Criteria for Crosswalk Width and Position at Signalized Intersections

Existing optimization methodologies for intersection operations assumes a fixed geometric design, however the geometry and operational system should be simultaneously optimized to produce the best performance. Signalized crosswalks are complex and critical pedestrian facilities. Their geometry and configuration directly affect the safety, cycle length and resulting delays for all users. As crosswalks become wider or they are placed further upstream, the cycle length will increase due to the all-red time requirement, which deteriorates the overall mobility levels of signalized intersections. In contrast, when crosswalk width decreases, the required minimum pedestrian crossing time increases due to the bi-directional pedestrian flow effects, which leads to longer cycle length. Furthermore, existing manuals and guidelines do not offer any specification for the required crosswalk width under various pedestrian demand conditions. This study aims to propose new criteria for designing crosswalk width at signalized intersections, which can optimize the performance from the viewpoint of vehicular traffic and pedestrians. The proposed methodology considers pedestrian demand and its characteristics （such as bi-directional flow effects）, vehicle demand and the geometric characteristics of the intersection The concept of optimized crosswalk width is proposed and demonstrated through a case study. Moreover, a comprehensive discussion regarding the merits and drawbacks of existing strategies on positioning crosswalks is presented. It was found that at signalized intersections, which are characterized by low pedestrian and high vehicle demands, crosswalk width of 2 meters is appropriate to minimize cycle length and resulting delays for all users including pedestrians.

Delays for Both Pedestrians Classified and Vehicles at a Signalized Crosswalk

Delays of both pedestrians,who are classified according to whether complying with traffic law,and vehicles at a signalized crosswalk are analyzed in this paper.The truncated Adams' model is applied to generate the probability and mean of delay of pedestrians non-complying with traffic law.Using the section-based traffic queuing-theory and the stochastic decomposition property of M/G/1vacation system with exhaustive service,the mean delay of vehicles is formulated.A multi-objective optimization model simultaneously minimizing the delays of pedestrians and vehicles during a signal period is proposed.The effects,which several model parameters have on the delays and the optimal solution of the model,are illustrated by numerical examples.

Study of pedestrian hybrid beacon's effectiveness for motorists at midblock pedestrian crossings

Pedestrian signals, particularly at signalized, midblock crossings, delay drivers, which is termed ＂unnecessary delay＂ in this study. A pedestrian hybrid beacon was proven to be effective in decreasing this unnecessary delay to the drivers at midblock pedestrian crossings when compared to standard signalized midblock crossings. Two pedestrian hybrid beacons were installed at midblock pedestrian crossings in Lawrence, Kansas. A study was conducted at these two locations to determine the effectiveness of the pedestrian hybrid beacon in decreasing the unnecessary delay to drivers by comparing them with a signalized midblock on Massachusetts Street, Lawrence, Kansas. In addition to the delay measurements for drivers at pedestrian hybrid beacon and signalized treatment at midblock pedestrian crossings, other parameters such as driver compliance rate, pedestrian compliance rate, and other driver and pedestrian characteristics were also studied. Video cameras were used at these test locations and the effectiveness of the pedestrian hybrid beacon was analyzed from the video. A more than 90% reduction in delays was observed for the drivers at the pedestrian hybrid beacon at midblock crossings compared to the signalized crossing. Further, a better driver compliance rate was also recorded at the pedestrian hybrid beacon. Information about reductions in unnecessary delay to drivers and improvements to driver and pedestrian compliance rates from the use of pedestrian hybrid beacons would be useful to engineers, decision makers, and researchers to determine an optimum treatment at desired pedestrian crossings.