Choosing to walk instead of using private cars or public transit has many direct benefits for the individual and collective benefits for urban populations indirectly (e.g., in the reduction of air pollution). In this study, walking preferences are analyzed taking into account the built environment, network design, and safety features for 15 intermediate-sized Iranian cities. Using a stated preference survey, a sample of more than 3600 work-trip cases was created and multinomial logit modeling was employed to determine significant contributing factors to a preference to walk. The findings indicate that network design variables have the greatest impact on the changes in walking mode choices, and improving them will increase walking choices by more than double. Safety variables increase walking choices by about 12%. Built environment factors only increase walking by about 9%. The results demonstrate that variables such as the level of traffic stress, intersections traffic control, pedestrian utilities, street network connectivity, and marked crosswalks and pedestrian bridges have the most influence on choosing to walk. Also, the modal shift analysis shows that changes in the quality of the variable groups have substantial effects on the choice to walk. Investments in upgrading the built environment, network design, and safety could lead to more than 47% of trips shifting from buses and private cars to walking. The proposed choice behavior analysis framework can be applied to active travel planning and policy evaluation. This research contributes to the growing debate about how to best assess, and model different approaches to active travel development for better public policy.