Development and Validation of a Paratransit Skills Assessment for Adults on the Autism Spectrum

Background: There is a wide body of literature that focuses on transportation for persons with developmental and cognitive disabilities, though there is limited published literature regarding transportation needs and barriers of autistic adults. The studies conducted on adults with autism are frequently mode specific and focused on driving, public transit, pedestrian, and travel training. The research focused on individuals with autism, or all developmental disabilities, using paratransit services is limited.

Objectives: The Paratransit Skills Assessment (PaSA) was developed in 2011 to assist individuals on the autism spectrum in accessing public paratransit services. The PaSA is a criterion-referenced assessment which was designed with three hierarchical sections for the three different paratransit service types as well as a trip planning and scheduling section (see Figure 1). It is composed of discrete 37 tasks that are used to make a determination if an individual can use paratransit independently. This report is on the validation of the PaSA.

Methods: The validation process was conducted with 98 study subjects who participated in the PaSA of which 86 were retested with 60 retests with non-paratransit users through in-vehicle trips and 26 current users through interviews about their revealed experiences in using paratransit services.

Results: The results of the data analysis find a high level of confidence in the PaSA results. The Kappa Statistic was generated after each vehicle trip to ensure that the blind-observers were in agreement on their observations. The majority of the observations were in almost perfect agreement while the lowest scores were in the moderate agreement range. The accuracy rate was 96.4%. The correlation coefficient was 0.995 illustrating high positive correlation with a strong linear and homoscedastic relationship. For a better understanding of the accuracy rate and correlation the Response Outcomes were analyzed, which found four tasks error rates exceeded the error rate of 0.05. These four tasks are: providing identification, time window, emergency: interacting with strangers, and emergency: lost off the vehicle. The accuracy rate for each discrete task was analyzed using the Wilcoxon signed-rank test indicating the results are significant. The Kuder-Richardson analysis found the 98 PaSA study participants result in a ρ = 0.894 indicating high reliability while not being homogeneous. The retests on the 60 in-vehicle participants and the 26 current users result in a ρ = 0.519 signifying the participants have moderate reliability while not being homogeneous. The cluster and dendrogram analyses illustrate the strong relationships within each group type as well as the overlap between the those with the highest skill set and the current paratransit riders. It should be noted that the accuracy rate for those who tested with only the six basic skills required tested significantly lower than those that tested in the other study groups.

Conclusions: The research findings including the high accuracy rate provide validation that the PaSA is a reliable method for predicting one’s ability to use paratransit services independently. These results can be useful for transit providers, transportation experts, and professionals working on issues with transportation disadvantaged population.