Evaluating the Effectiveness of Roadside Instruction in Teaching Youth With Visual Impairments Street Crossings

Abstract

A single-participant multiple probe design across participants was used to evaluate the effectiveness of verbal rehearsal and graduated guidance to teach youth who were blind how to cross the street. This study replicated intervention procedures across settings along with the staggered entry of participants. Individuals learned to cross one or two intersections. Maintenance was assessed, and generalization was assessed at a third intersection. Visual analysis of graphed data indicated that verbal rehearsal and graduated guidance were effective for all participants who received instruction. The participants ranged from 13 to 20 years of age and had light perception or less. All participants who received instruction maintained at levels substantially above baseline and generalized the majority of skills to a third intersection.

Keywords

verbal rehearsal graduated guidance life skills blind or visual impairments

Orientation and mobility (O&M) is an area of instruction focusing on teaching individuals who are blind and visually impaired to orient mentally and travel physically in their environments (Hill & Ponder, 1976). O&M instruction often involves teaching individuals who are blind or visually impaired to use tools such as canes or optical devices. It also involves teaching individuals to travel in a variety of settings such as the home, school, or workplace, and the broader community that includes crossing streets (Blasch, Wiener, & Welch, 1997; Hill & Ponder, 1976; Jacobson, 1993). The ability to cross streets safely provides more opportunities for individuals to function independently in their communities (Horner, Jones, & Williams, 1985; Mowafy & Pollack, 1995). These opportunities include socializing, using public transportation to travel to work, activities, and services (Bart, Katz, Weiss, & Josman, 2008). The ability to travel and cross streets for business and pleasure increases individuals’ functional independence (Katz et al., 2005).

Street crossing is a common but dangerous activity. In 2009, approximately 63,100 pedestrians sustained injuries or were killed due to motor vehicles. Approximately 21,500 of these victims were children (National Highway Traffic Safety Administration, 2011), perhaps because they are less skilled in making decisions about traffic (Pitcairn & Edlmann, 2000). This task is even more difficult for individuals without vision who cross streets using auditory cues. Individuals who use sound cues for gap detection and intersection alignment tend to perform these tasks with reduced accuracy (Guth, Hill, & Rieser, 1989). A broad body of research, however, has investigated the effectiveness of teaching high-risk populations, children, and individuals with disabilities other than visual impairments about street crossing.

As of 2011, 17 experimental studies were identified evaluating procedures to teach children without disabilities to cross streets, and 8 experimental studies were identified evaluating interventions to teach individuals with disabilities other than visual impairments street crossing. These studies used a variety of methods and contexts, including virtual reality (Bart et al., 2008; Tolmie et al., 2005), classroom-based instruction (Batu, Ergenekon, Erbas, & Akmanoglu, 2004; Miller & Davis, 1984), roadside instruction (Thomson & Whelan, 1997; Yeaton & Bailey, 1978), or a combination of these methods (Limbourg & Gerber, 1981; Thomson et al., 1998). A total of 4 studies compared roadside instruction with classroom-based instruction and found that roadside instruction was more effective when participants were assessed with actual crossings (Collins, Stinson, & Land, 1993; Limbourg & Gerber, 1981). Most instruction of street crossing for students who are visually impaired occurs roadside (Jacobson, 1993); no studies were found evaluating methods for teaching street crossing to individuals with visual impairments.

Street crossing is a chained skill with well-defined, observable behaviors. Researchers and educators have successfully taught chained skills with graduated guidance (Schepis, Reid, & Behrman, 1996; Sisson, Kilwein, & Van Hasselt, 1988). Due to the effectiveness of graduated guidance with chained skills, it was selected as the primary approach for teaching street crossings in the current study. In addition, participants used verbal rehearsal, stating each step of the street crossing chain prior to doing the crossing. Some evidence suggests that verbal rehearsal benefits short-term (Baddeley, 1986; Bjork, 1975; Horton, Hay, & Smyth, 2008) and long-term memory (Horton et al., 2008) as well as behavioral maintenance (Baddeley, 1981).

In the current study, a protocol for teaching the chained skill of street crossing using graduated guidance paired with verbal rehearsal was evaluated. The study was implemented using roadside instruction to determine whether graduated guidance paired with verbal rehearsal was effective in teaching children with visual impairments to cross streets. Maintenance and generalization were assessed roadside. The study attempted to answer the following questions: (a) Do participants whose sole disability is light perception (LP) or less learn to cross streets accurately and safely when taught with graduated guidance and verbal rehearsal? (b) Do participants who learn to cross streets when taught with graduated guidance and verbal rehearsal maintain accurate and safe street crossings when assessed on previously instructed intersections? (c) Do participants who learn to cross streets when taught with graduated guidance and verbal rehearsal generalize these skills to intersections where they have received no instruction?

Method

Participants

This single-participant study involved four participants. Inclusion criteria were (a) demonstration of concepts related to travel and street crossing (e.g., left, right, positional concepts), (b) ability to maneuver independently with a long cane, (c) ability to detect surface changes and drop-offs, (d) LP or less in both eyes, and (e) an age between 7 and 21 years. Exclusion criteria were (a) additionally diagnosed severe disabilities, (b) prior instruction in street crossings, and (c) a functional hearing loss. Inclusion and exclusion criteria were measured by the first author, a certified O&M specialist (COMS), using portions of TAPS: An Orientation and Mobility Curriculum for Students With Visual Impairments (Pogrund et al., 2005). Medical records and assessments were reviewed. Furthermore, a COMS at the participants’ school was interviewed about participants’ current skills. This ensured that none of the participants had additional disabilities and had no prior formal education in street crossing.

Participant 1 was a 16-year-4-month-old female. She lost vision adventitiously at 14 years of age due to a brain tumor; her visual acuity was listed as LP in both eyes (OU). She had been a cane traveler for 2 years and had adequate skills to travel independently in the school and detect surface changes and drop-offs. She had a thorough understanding of directional and positional concepts. When her hearing was assessed, the results of her otoscopy and tympanometry were normal. The audiologist found that Participant 1’s hearing thresholds were within normal limits for all frequencies tested in both ears.

Participant 2 was a 14-year-10-month-old male. He was congenitally blind due to retinopathy of prematurity (ROP). His visual acuity was no LP (NLP) OU. He has been a cane traveler since 5 years of age and used the cane to travel independently in the school. He detected surface changes and drop-offs with ease in familiar environments, and had adequate understanding of directional and positional concepts. When his hearing was assessed, the results of his otoscopy and tympanometry were normal. The audiologist found that his hearing thresholds were within normal limits for all frequencies tested in the right ear but found a mild hearing loss from 2000 to 4000 Hz in the left ear. The audiologist stated that it did not meet the definition of functional hearing loss. Thresholds at all other frequencies tested were within normal limits.

Participant 3 was a 20-year-0-month-old female. She was congenitally blind due to optic nerve hypoplasia. Her acuity was NLP OU. She has been a cane traveler since 12 years of age and used the cane to travel independently in the school. She detected surface changes and drop-offs in familiar environments, and had adequate understanding of directional and positional concepts. When her hearing was assessed, the results of her otoscopy and tympanometry were normal. The audiologist found that Participant 3’s hearing thresholds were within normal limits for all frequencies tested in both ears.

Participant 4, who served as a control and did not receive instruction, was a 13-year-11-month-old female. She was congenitally blind due to ROP. Her visual acuity was NLP in the right eye (OD) and LP in the left eye (OS). She has been a cane traveler since 5 years of age and used the cane to travel independently in the school. She detected surface changes and drop-offs easily in familiar environments, and had adequate understanding of directional and positional concepts. When her hearing was assessed, the otoscopy exam revealed nonimpacting cerumen bilaterally. The tympanic membrane was partially visible in both ears. The tympanometry could not be completed because the participant did not tolerate it. The audiologist found that Participant 4 had a slight hearing loss in the left ear at 250 Hz rising to normal thresholds from 500 to 8000 Hz. The cerumen in the ear may have caused the slight hearing loss. The audiologist stated that it did not meet the definition of a functional hearing loss. In the right ear, the audiologist found normal hearing thresholds from 250 to 8000 Hz.

The COMS who typically taught the participants in the school participated as an instructor. Inclusion criteria for instructors were certification as an O&M specialist, access to a student meeting the inclusion criteria, and willingness to participate. The COMS who typically taught the students in the school was a male with a master’s degree and some doctoral work. He had 41 years of experience teaching O&M to students with visual impairments and was certified by the Academy for Certification of Vision Rehabilitation and Education Professionals (ACVREP). The first author, who provided the bulk of instruction, was a female doctoral student . She had obtained certification in O&M at the master’s degree level, had 4 years of experience teaching O&M, and was certified by ACVREP.

Setting

Assessment for inclusion criteria took place at the students’ school. Data collection for probe and instructional sessions occurred roadside at three intersections. Intersection 1 was a residential, two-lane (one lane in each direction), plus-sign intersection with little traffic. The traffic running parallel to the crossing was controlled by a stop sign; the perpendicular traffic had the right-of-way and did not stop. Participants were taught to cross this intersection when it was “all quiet” (no traffic). Intersection 2 was a busier, residential, and light commercial two-lane (one lane in each direction), plus-sign intersection. The perpendicular traffic flowed freely without control; the parallel traffic was controlled by a stop sign. Parallel traffic was rare, and perpendicular traffic was frequent. Ideally, participants would have been taught to cross the intersection with the parallel traffic surge. Parallel traffic was unreliable, so this intersection became an instance in which participants crossed when all was quiet. Intersection 3 was a residential, two-lane (one lane in each direction), plus-sign intersection with light to moderate traffic. Parallel and perpendicular traffic were controlled with stop signs (four-way stop). Participants had the option of crossing with the parallel traffic surge or when the intersection was all quiet.

Materials

A video recording of the first author teaching a sighted but blindfolded adult (second author) to cross the street using a cane was used to train the second observer and the instructor. Sessions were video recorded. Students were allowed to use their personal long canes, which were all folding canes with pencil tips.

Response Definitions and Measurement

The behaviors measured in verbal rehearsal and street crossing included finding the curb with the cane, stepping up to it, lining up for the crossing (perpendicular to the traffic), taking one step back, sweeping the area in front of the feet with the cane, holding the cane in the “ready position” (diagonally across the body), describing the parallel and perpendicular traffic, and how each was controlled, identifying a sufficient gap in traffic for the crossing, walking quickly, walking without veering left or right, finding the opposite curb, and stepping out of the street. These behaviors were compiled from O&M textbooks (Hill & Ponder, 1976; Jacobson, 1993).

All roadside sessions were video recorded. Operationalized definitions that included examples and nonexamples were used as a guide when the videos were coded. Observers watched the videos, and coded the verbal rehearsal and crossing by marking each behavior listed in the task analysis in one of six ways. The step was an unprompted correct if the participant did the behavior independently. The step was a prompted correct if a brief, general verbal prompt was given and the student did the behavior correctly (e.g., instructor asks, “What about traffic?” and the student responds). The step was an unprompted incorrect if the participant did a step incorrectly without a prompt. The step was a prompted incorrect, if the participant did a behavior incorrectly and received a prompt (e.g., participant veers to the left; instructor says, “You’re veering to your left”). The step was an unprompted no response if the participant did not do the step and did not receive a prompt. The step was a prompted no response if the participant was prompted and did not do the behavior (e.g., instructor prompts, “Tell me about traffic,” and the participant does not respond). Multiple opportunity probe trials were used, so participants always had an opportunity to complete each step of the behavior chain. Only unprompted correct responses were counted as successful attempts in terms of meeting criterion.

The first author and a doctoral student coded the video records. After receiving a copy of the protocol and definitions of behaviors, the observers trained using the same video used to train the instructor. Interobserver agreement (IOA) was measured by comparing the records from both observers (Ayres & Gast, 2010). IOA was calculated by dividing the number of agreements by the number of agreements plus disagreements and multiplying the quotient by 100. In probe conditions, IOA data were collected for a minimum of 33.3% of the sessions for each participant; it was 94.2% (R = 88.1%–100%). In instruction, IOA data were collected for a minimum of 27.3% of sessions for each participant; it was 99.8% (R = 92.9%–100%).

Procedural Fidelity

Procedural fidelity was measured using a checklist of behaviors for verbal rehearsal and the crossing, and during probe and instructional conditions (see Figure 1). In verbal rehearsal and the crossing, the coder marked whether each step was addressed and whether praise or a prompt was delivered because none should have occurred in probes and one or the other should have occurred for each step depending on participant performance in instruction. Procedural fidelity was calculated for each session by adding the number of correctly given prompts and praise, and then dividing by the total number of steps that should have been addressed using either prompts or praise and multiplying by 100. This resulted in a percentage of instructor behaviors done with fidelity. When total procedural fidelity fell below 90% for any tier, the study was halted and the instructor was retrained using video recordings. Procedural fidelity data were collected for a minimum of 33.3% of each probe condition for each of the four participants. Procedural fidelity in the probe conditions was 99.9% (R = 98.2%–100%). Procedural fidelity data were collected for a minimum of 36.4% of instructional sessions. In instruction, procedural fidelity for verbal rehearsal was 83.9% (R = 0%–100%); for crossing, it was 88.1% (R = 14.8%–100%). Procedural fidelity information organized by participant and condition is displayed in Table 1.

Figure 1.

Procedural fidelity data collection sheet.

Table 1.

Procedural Fidelity: Percentage of Correct Implementation by Condition and Participant.

	Probe 1	Instruction 1		Probe 2	Instruction 2		Probe 3	Probe 4
Participants	C	VR	C	C	VR	C	C	C
Participant 1
Percentage of agreement	100	87.7	92.6	100	73.2	78.7	100	NA
Range	100–100	74.1–100	88.9–100	100–100	40.7–100	14.8–100	100–100
Percentage of sessions measured	33.3	42.9	42.9	33.3	36.4	36.4	33.3
Participant 2
Percentage of agreement	100	61.1	69.1	100	98.8	100	98.2	100
Range	100–100	0–97.5	14.8–100	100–100	97.5–100	100–100	98.2–98.2	100–100
Percentage of sessions measured	33.3	42.9	42.9	33.3	40	40	33.3	33.3
Participant 3
Percentage of agreement	100	98.5	100	100	NA	NA	100	100
Range	100–100	92.6–100	100–100	100–100			100–100	100–100
Percentage of sessions measured	33.3	45.5	45.5	33.3			33.3	33.3
Participant 4
Percentage of agreement	100	NA	NA	100	NA	NA	100	100
Range	100–100			100–100			100–100	100–100
Percentage of sessions measured	33.3			33.3			33.3	33.3

Note. VR = verbal rehearsal; C = crossing. Verbal rehearsal was not used during probes; therefore, procedural fidelity is not reported.

There were two sessions when the procedural fidelity fell below the minimum of 90% when the principal investigator (PI) was providing instruction at the first intersection with Participant 1. When this was noted, the videos were reviewed to double check which portions of the procedure had been violated. In most cases, the problem was a lack of praise after correctly executed behaviors. The protocol was reviewed, and procedural fidelity with the PI returned to acceptable levels. The other COMS only proved instruction on 1 day. This instruction was with Participant 1 at the second intersection and Participant 2 at the first intersection. Procedural fidelity levels were unacceptably low that day: 40.7% during verbal rehearsal and 14.8% during the crossing for Participant 1, and 0% during verbal rehearsal and 14.8% during the crossing for Participant 2. The instructor provided virtually no praise or prompts during the crossing. The COMS did not provide any further instruction during data collection, so he was not retrained on the protocol. If it had been necessary for him to provide further instruction, he would have been retrained before this was permitted. The low procedural fidelity levels of the COMS brought down the total fidelity levels during instruction. Procedural fidelity without the sessions provided by the COMS was 89.5% (R = 0%–100%) for verbal rehearsal; for crossing, it was 95.2% (R = 14.8%–100%).

Experimental Design

A multiple probe design across participants and replicated across settings (intersections) was used to assess the effectiveness of verbal rehearsal plus graduated guidance. During probe conditions, each participant was assessed at each of the three intersections for three sessions. The initiation of instruction was staggered across participants to ensure that experimental control was possible if participants generalized from the first intersection to the second or third. After all participants completed the Probe 1 condition, Participant 1 received instruction on the first intersection. Criterion performance was measured as completing each step of the rehearsal and crossing with 100% unprompted accuracy during three trials per session for three consecutive sessions. When Participant 1 met criterion, Probe 2 was initiated for all participants; after Probe 2, Participant 2 received instruction on the first intersection and Participant 1 on the second. When Participant 2 met criterion, Probe 3 was initiated for Participants 2, 3, and 4; after Probe 3, Participant 3 received instruction on the first intersection. After Participants 1 and 2 met criterion on the first intersection, including the respective probe conditions, they moved to subsequent probe conditions and intersections dependent on their own performance. School closed during data collection, because of severe flooding, and no time existed for Participant 3 to receive instruction at the second intersection or for Participant 4 to receive any instruction. Therefore, Participant 4 served as a control in the study; she received street crossing instruction from her school’s COMS later.

Procedures

Probe procedures

Probe conditions occurred before and after each instructional phase. Participants’ performance on the three intersections was assessed daily for three sessions in each probe condition. Probe sessions had one trial (crossing) per intersection using multiple opportunity procedures; verbal rehearsal and graduated guidance were not used. The instructor guided the student to the intersection, so the student was directly facing the intersection approximately two steps from the curb and asked the participant to cross the street. The instructor did not provide any orientation to the intersection, instruction, or feedback before, during, or after the crossing. The instructor intervened only in cases when the participant made a decision that was considered unsafe (e.g., stepping in front of a car, veering so that the target curb was missed and subsequently walking in the parallel street). The participant was allowed to complete the entire crossing even if errors occurred early in the behavior chain. When the crossing was complete, the instructor thanked the participant.

Intervention procedures

Each session began with verbal rehearsal of the steps in safe street crossing and involved three trials (crossings) per session. In the initial session at the first intersection, the instructor stated each step to the participant. In subsequent sessions, the instructor asked the participant to state each step she or he was to do before beginning the crossing. Each time the participant stated a correct step in a logical order, the instructor delivered general praise (e.g., “good,” “correct”). If the participant made an error, the instructor stopped the student and provided a verbal prompt (e.g., “What are you going to tell me about the traffic?”).

After verbal rehearsal, the instructor said, “Let me see you do everything you just told me.” Full verbal prompting was used in the first session of the first intersection. The instructor verbally guided the student through each step by, for example, saying, “Find the curb with your cane. Good. Now step up to it. Good.” After this session, the instructor told the participant to begin the crossing and allowed the participant to do the crossing. When the participant did the steps correctly and in the correct sequence, the instructor delivered brief praise (e.g., “good,” “nice job,” “correct”) and allowed the participant to continue. If the participant paused or made an error (e.g., forgot to describe the traffic), the instructor immediately corrected the student verbally (e.g., “Be sure to tell me about traffic”). All prompts began as verbal prompts; however, physical prompts were used if the participant did not successfully complete the behavior (e.g., did not understand how to sweep the cane correctly) or if the participant was in danger. The intervention continued until the participant completed each step of the rehearsal and crossing with 100% unprompted accuracy during three trials per session for three consecutive sessions.

Results

Acquisition, Generalization, and Maintenance of Street Crossing Chains

The performance of the participants on Intersections 1, 2, and 3 is shown in Figures 2 to 4, respectively. Instruction (verbal rehearsal and graduated guidance) for Intersection 1 was introduced in a time-lagged fashion across participants. Specifically, after Probe Condition 1, Participant 1 received instruction on Intersection 1, and Participants 2, 3, and 4 did not receive instruction. When Participant 1 performed at criterion-level responding on Intersection 1, Probe Condition 2 was implemented. After Probe Condition 2, instruction was applied to Participant 1 on Intersection 2, Participant 2 on Intersection 1, and Participants 3 and 4 did not receive instruction. When Participant 2 performed at criterion-level responding on Intersection 1, Probe Condition 3 was implemented for Participants 2, 3, and 4. After Probe Condition 3, Participant 2 received instruction on Intersection 2, and Participant 3 received instruction on Intersection 1; Participant 4 did not receive instruction. Participants 1 and 2 were taught at two intersections (Intersections 1 and 2), Participant 3 was taught only at Intersection 1, and Participant 4 served as a control participant and was not taught at any intersection.

Figure 2.

Percentage of street crossing behaviors completed correctly by each participant at Intersection 1.

Figure 3.

Percentage of street crossing behaviors completed correctly by each participant at Intersection 2.

Figure 4.

Percentage of street crossing behaviors completed correctly by each participant at Intersection 3.

Prior to instruction, as shown in Figures 2 to 4, none of the participants performed above 50% correct on any of the intersections. The introduction of instruction (verbal rehearsal and graduated guidance) resulted in abrupt positive increases in participants’ unprompted correct responses, which were characterized as positive-level shifts and accelerating trends (see Figures 2 –4). No overlapping data occurred between preinstructional probe conditions and subsequent instructional conditions for Participant 1 on Intersection 1, Participant 2 on Intersections 1 and 2, and Participant 3 on Intersection 1. The only instance of overlapping data from preinstructional probe conditions to instructional conditions occurred for Participant 1 on Intersection 2; the percentage of nonoverlapping data was 90.9% (1 of 11 intervention data points). Thus, a functional relation was shown between the instruction and the percentage of unprompted correct performance for Participants 1, 2, and 3 on Intersection 1, and was replicated for Participants 1 and 2 on Intersection 2. Furthermore, no substantial shifts occurred in the percentage of unprompted correct performance across probe conditions for any of the intersections for Participant 4 who did not receive instruction.

Following instruction on any intersection for Participants 1, 2, and 3, performance in subsequent probe conditions of untreated intersections or intersections where instruction had not yet occurred showed increases in correct performance (see Figures 2 –4) as a result of generalizing skills learned at the previous intersections; however, this increase in correct performance was not to criterion-level responding. Thus, after instruction on Intersection 1, generalization occurred to untreated intersections, but that generalization was not sufficient to forego instruction of those intersections. In probe conditions after instruction on any given intersection, participants’ performance in postinstruction probe conditions (i.e., maintenance) was above that of preinstruction probe conditions. However, this performance tended to be slightly lower than criterion-level performance.

Types of Errors

Although the crossing was considered a chained behavior, it contained different elements in which errors were possible, including (a) setting up for crossing (finding the curb, aligning for crossing, moving back to be one step from the curb, sweeping with the cane to identify obstructions and holes, and holding the cane in the ready position), (b) describing traffic patterns, (c) starting to walk at a sufficient traffic gap to cross safely, (d) veering (out of the cross walk) during the crossing, (e) walking quickly or the duration of crossing, and (f) completing the crossing (finding the opposite curb and stepping out of the street). Results are presented below for Participants 1, 2, and 3 in three situations: before instruction on any intersection, after instruction on the instructed intersections (maintenance), and after instruction but on intersections in which instruction had not yet occurred (generalization).

Before instruction, all three participants made errors on setting up for a crossing and describing the traffic patterns. Participants 2 and 3 made errors in veering, walking too slowly, and completing the crossing. Participants 1 and 3 made errors in discriminating when to walk. For maintenance, all participants made errors in describing the traffic patterns. Participant 1 made occasional errors in veering, and Participant 2 made occasional errors in veering and completing the crossing. For generalization, all participants made errors in describing the traffic patterns, veering, walking quickly enough, and completing the crossing. Participants 1 and 2 made errors related to discriminating when to start walking.

Discussion

The purpose of this study was to evaluate the effectiveness of verbal rehearsal and graduated guidance in teaching participants with LP or less to cross streets safely and independently. Maintenance and generalization of the steps involved in street crossing were also measured. From the study, three major findings emerged. First, the combination of verbal rehearsal and graduated guidance produced criterion-level responding (i.e., 100% unprompted correct crossings for three consecutive days) at the intersections in which instruction was provided. This finding replicates earlier research on the benefits of verbal rehearsal (Baddeley, 1986; Horton et al., 2008) and graduated guidance that had been conducted primarily with students with intellectual disabilities (e.g., Foxx & Azrin, 1973; Schepis et al. 1996; Sisson et al., 1988). In previous graduated guidance research, however, physical prompts were used exclusively; in this study, the prompts were almost exclusively verbal. This appears to confirm the assumption that the controlling nature of the prompt and the timing of removal are the critical elements in the transfer of stimulus control rather than the type of prompt (physical, verbal, model) used during instruction (Wolery, Ault, & Doyle, 1992). When questioned, Participant 1 indicated that the praise for steps completed correctly (a critical element of graduated guidance) was the most helpful aspect of the instruction. After instruction at the first intersection, Participant 1 expressed frustration during probe sessions at the second and third intersections, because she said she wanted feedback and correction on what she was doing wrong. Participant 1 noted that the verbal rehearsal became redundant as she mastered the skills for crossing the street; however, she said it was “necessary” for her in the beginning “to get the steps in her head.” During instruction at the first intersection, Participant 3 indicated that talking through the steps (the verbal rehearsal) before crossing made her “feel better.”

Second, the verbal rehearsal and graduated guidance produced maintenance of the steps involved in street crossing but not at criterion-level performance, in most probe sessions. Strategies for promoting maintenance include thinning reinforcement schedules, overlearning (having stringent criterion levels), and verbal mediation (Cooper, Heron, & Heward, 2007). The reinforcement schedule was not systematically thinned in this study, and this is an area in which additional research could be conducted. Students had a fairly high criterion (i.e., 100% unprompted correct across 3 days), but this amounted to 9 consecutive crossings over 3 days. Perhaps a more stringent criterion of 15 or 20 consecutive crossings over multiple days is necessary. With safety skills, high criterion levels to maximize overlearning are often warranted, because errors can result in drastic consequences. For example, initiating the crossing in an insufficient traffic gap could result in injury or death. During maintenance, the errors were in describing traffic patterns (all participants), veering (two participants), and completing the crossing (two participants). Clearly, veering and completing the crossing are critical steps; however, describing the traffic patterns gives important clues about when crossings should occur. Prior research documented that individuals who are blind often cannot align adequately based only on auditory cues (D. H. Ashmead, R. Wall Emerson, & D. W. Grantham, personal communication, June 16, 2010; Guth et al., 1989). Describing the traffic patterns, in addition to finding the curb with the cane, may help in alignment that, over time, may assist with veering.

Third, although generalization occurred once instruction was given on the first intersection, performance was not at criterion levels. Each participant had higher percentages of unprompted correct responses on untreated (generalization) intersections after learning to cross another intersection. The analysis of errors, however, suggests this generalization, although desirable, was not adequate for safe crossings. Participants made errors on critical elements of safe crossing, including discriminating when to cross, veering, walking too slowly, and completing the crossing. Any of these errors could result in an unsafe crossing.

Future Research

Future research should focus on a number of issues related to teaching safe and independent street crossing. Children without disabilities and individuals with disabilities other than visual impairments have benefited from using maps and models when learning to cross streets (Batu et al., 2004; Page, Iwata, & Neef, 1976). Studies involving participants with visual impairments found that spatial awareness and cognitive mapping abilities were improved when tactile maps and models were used (Sapp, 2003; Ungar, Blades, & Spencer, 1996; Ungar, Blades, Spencer, & Morsley, 1994). Perhaps incorporating tactile maps or models prior to roadside instruction as well as using verbal rehearsal and graduated guidance would add conceptual understanding for students with visual impairments and reduce errors, particularly those associated with describing traffic patterns. In probe sessions, participants sometimes veered and failed to find the opposite curb, and proceeded to walk down a parallel street until the instructor intervened; however, the participants never seemed to notice they had been walking too long. Perhaps initial instruction with a tactile map or model, or instruction in time/distance estimation would have given them the expectation that after a certain distance, they should encounter a curb; otherwise, they had made an error in crossing. Similarly, the errors of participants walking too slowly might be alleviated by having the student cross the street using a human guide technique and counting the number of seconds required for the crossing. This count could be built into the verbal rehearsal. This technique would be less abstract than using a map or model, but the goal of orienting the participant to the intersection prior to direct instruction in crossing would be the same.

Another direction for future research is related to1:1 versus small group instruction. Currently, almost all O&M instruction is provided one-on-one. For children without disabilities, teaching a triad of students has been more successful than 1:1 instruction (Tolmie et al., 2005). The authors theorized that this was because the students worked together to solve the problems through small group consensus building, proposing ideas, and debating solutions. This approach may encourage participants to problem solve rather than to simply follow instructions from an adult. Small group instruction may provide participants with the skills needed in generalizing to new intersections. A variation of small group instruction may be to include peer tutors who were competent in crossing streets (Blew, Schwartz, & Luce, 1985).

Future research should also focus on studies with younger children who are crossing streets. The participants in this study were much older than the participants in the literature about children without disabilities who learned to cross streets. It is currently unknown whether there is an age at which it is typical for an individual with a visual impairment to learn to cross streets.

Finally, research is needed on training others to use the procedures of this study when teaching street crossing. The researcher (T.S.W.) attempted to train a practicing COMS to use the procedures through written and verbal instructions, and showing a video. However, most of the procedural errors in the study were done by the practicing COMS. It is unclear whether more instruction and feedback would have resulted in higher levels of fidelity. The current study does not bear on how to teach untrained individuals (e.g., university students) to use these procedures.

Limitations

This study, as with others, has limitations. One limitation focuses on the difficulties in finding appropriate intersections for teaching. An ideal intersection would include a sidewalk, a clean, identifiable curb line, an opposite curb positioned directly across from the beginning curb, and consistent traffic to serve as auditory cues. In this study, the traffic flow was unreliable, which may have contributed to the participants’ difficulties in describing traffic patterns. In addition, the curb at the second intersection was rounded with a small amount of damage to the pavement at the curb, so participants had to step just to the left of the curb to find a straight tactile cue and avoid stepping on uneven pavement. Another weakness related to the use of the video camera in recording the crossings. Although it was useful in many aspects, on some occasions it was limiting because it was hard to hear the participants and it did not capture the entire milieu in which participants were crossing. Finally, closure of school due to flooding precluded having more replications of the effect.

In this study, verbal rehearsal and graduated guidance delivered roadside resulted in participants learning to cross intersections, and produced high levels of maintenance at intersections where participants received instruction and led to some generalization to untrained intersections. This suggests that the combination of verbal rehearsal and graduated guidance are effective methods of teaching adolescents with visual impairments and no additional severe disabilities to cross streets when instruction is delivered roadside. The finding, however, is limited to cane users who have the inclusion criteria noted earlier. This study was the first experimental investigation examining how to teach individuals with visual impairments to cross streets. Given the high-risk nature of street crossing and its value to individuals with visual impairments, additional studies are needed to replicate this study, and identify other effective and efficient methods for teaching safe, independent, and generalized street crossing.

Footnotes

Declaration of Conflicting Interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

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