In Australia, pedestrian injury is a leading contributor of child mortality and a prevalent cause of disability among five to nine year old children. While parent involvement is fundamental for the development of safer road user behaviors among children, few studies have examined the extent to which parents participate in and implement program activities and how this is linked to study outcomes.

This study conducted a process evaluation on the three-year Walk with your Kids (WWYK) Project involving a cohort of 621 four-year old children and their parents from 13 elementary schools located in socio-disadvantaged areas in Perth, Australia. The purpose was to investigate the extent of implementation and satisfaction with a comprehensive school and home-based pedestrian safety intervention and the extent to which implementation was associated with changes in parents' pedestrian safety behaviors and knowledge. Process and outcome data were collected at four time points using teacher self-report questionnaires, teacher implementation monitoring logs, parent self-report questionnaires and student-parent work samples. Mixed-effects models were used to analyze the association between implementation dose and outcomes.

Variability in the extent of implementation was evidenced by teachers and parents, with the highest rates of implementation occurring in the first year. Individuals receiving higher doses of the WWYK intervention showed the strongest improvements in parent pedestrian safety knowledge and behaviors. These associations were more pronounced for the first year and cumulatively over the three years. Parent activities dose was positively associated with study outcomes over and above the classroom activities dose, signifying that the parent component may explain more of the changes in parent's behavior and knowledge than the classroom component.

These findings highlight the importance of process evaluation, not merely to monitor implementation, but to also examine the relationships between implementation and study outcomes to strengthen the outcome evaluation findings. The value of including a parent component in school-based pedestrian safety programs was demonstrated with parents having the capabilities of effectively providing the required practical road crossing training with young children. Further development of standardized guidelines for the concepts and measurement of process evaluation will facilitate more rigorous and consistent monitoring of implementation.