The "Safe Routes Improvement Act" amends title 23, United States Code, to establish a new requirement for states participating in the Safe Routes to School program. Each state must now designate a dedicated coordinator for the program, ensuring a clear point of contact for its implementation and management. This coordinator's primary duty is to serve as the official point of contact for the Safe Routes to School program within their state. States are permitted to utilize existing employees for this role and can fund the coordinator's salary using existing federal allocations under sections 133(h) or 148. To ensure transparency and accessibility, each state is required to publish the coordinator's contact information on its department of transportation website, and any vacancy in the position must be filled within 180 days.