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93 tested in this research generally served their intended pur- pedestrians who are blind that they are leaving the pedestrian pose; however, the selected type of material evaluated proved way and entering the vehicular way. Also, planting strips along to be too quiet given the high ambient noise at the test site. the sidewalk serve as a barrier that discourages pedestrian The biggest problems with the treatment arose when vehicles access to the roadway at places other than the crosswalk and were traveling very slowly and the audible cues from the sound make it less likely that a blind pedestrian will inadvertently step strips were not noticeable. from the paved walkway into the paved roadway at any point The use of a pedestrian signal at the CTL is a possible treat- other than the crosswalk or begin crossing from the wrong ment that can be tied in with the existing signal control at the point without realizing the intersection is a roundabout. They main intersection. There are some challenges to tying the CTL also provide a trailing surface that long cane users can use to signal into the existing controller, especially when an intersec- locate the crosswalk. tion has multiple CTLs that are to be signalized. But an exist- The splitter island should be wide enough for pedestrian ing signal phasing strategy is to use vehicle overlap phasing refuge and to enable a two-stage crossing. Note that splitter with a pedestrian signal across the crosswalk. If adding the CTL islands that are not raised islands but are simply painted on signal to an intersection with a long cycle, the expected pedes- the pavement are not detectable to blind pedestrians. trian delay may be high and needs to be assessed in the context Several blind pedestrians commented that landscaping of the total pedestrian crossing. At a busy intersection such and trees on the splitter island (at the two-lane roundabout) as the test site, a diagonal pedestrian crossing (e.g., from the blocked some of the sound from the lane behind them when southeast to northwest corner) would entail the use of four sig- they were crossing from the island to the curb. This helped nalized crossings (CTL, main road, side road, CTL). Signalized with sound separation and discrimination of the traffic com- CTLs have been observed in several cities across the United ing toward them from the traffic going away from them, and States and are rather common in other countries. may therefore be beneficial for single-lane roundabouts as In addition to a standard pedestrian-actuated signal, a well. Landscaping on the splitter islands should not block the PHB may be another alternative for CTLs. The advantages of view of the crosswalk for drivers. the allowable vehicle movements during the "Flashing Red" phase are reduced with shorter crossings and associated shorter Two-Lane Roundabouts "Flashing Don't Walk" phases. However, some vehicle delay savings are expected to remain. The allowable provision in The two-lane roundabout design should promote low speeds the MUTCD to let the pedestrian display at the PHB rest in a at the crosswalk through geometric design, where possible, or dark mode may be considered for CTLs since many (sighted) through supplemental traffic-calming treatments (bulb-outs pedestrians may not require the added assistance provided by or raised crosswalks). The raised crosswalk design showed the signal. potential at the tested location and resulted in significantly reduced pedestrian delay and interventions; however, there is concern related to observed multiple threat conflicts, and more Single-Lane Roundabouts research is need to clarify risk. The impact on traffic operations The design of single-lane roundabouts should encourage is believed to be directly related to the design of the raised cross- low vehicle speeds in the vicinity of the crosswalk. Low speeds walk (vertical elevation and transition slope). In the tested are shown to correlate with increased yielding behavior and installations, vehicle impacts were reasonable. More testing is reduced injury in case of a collision. There is some concern that necessary to ensure that this treatment has broader applica- lower speeds (and associated lower vehicle noise) may reduce tion to other geometries and traffic patterns. the ability of a blind pedestrian to detect crossing opportunities The use of a PHB showed promise at the tested location in (yields), which is a question that deserves the attention of terms of reducing pedestrian delay and interventions, but was researchers. associated with some misunderstanding and/or noncompli- The design of a single-lane roundabout should encourage ance on the side of drivers and blind study participants. A narrow (or standard) lane widths in the vicinity of the cross- simulation-based sensitivity analysis showed that the use of the walk. Lanes that flare out too early unnecessarily increase the PHB phasing, a two-stage crossing, and an offset exit portion crossing distance for pedestrians and further may allow vehi- of the crosswalk all result in improvements to vehicular oper- cle passing in the vicinity of the crosswalk, thereby creating a ation compared to a standard one-stage pedestrian-actuated potential multiple-threat situation. This was observed at one signal. If signalization is considered at a two-lane roundabout, of the three tested single-lane roundabouts and resulted in these alternate signalization strategies should be considered. some near-interventions. Detectable warnings complying with the draft PROWAG Detectable warnings complying with the draft PROWAG are required at both curb and island ends of crosswalks to warn are required at both curb and island ends of crosswalks to warn pedestrians who are blind that they are leaving the pedestrian