Book excerpt: Vehicle-bridge interaction happens all the time on roadway bridges and this interaction performance carries much useful information. On one hand, while vehicles are traditionally viewed as loads for bridges, they can also be deemed as sensors for bridges' structural response. On the other hand, while bridges are traditionally viewed as carriers for vehicle weight, they can also be deemed as scales that can weigh the vehicle loads. Based on these observations, a broad area of studies based on the vehicle-bridge interaction have been conducted in the authors' research group. Understanding the vehicle and bridge interaction can help develop strategies for bridge condition assessment, bridge design, and bridge maintenance, as well as develop insight for new research needs.This book documents fundamental knowledge, new developments, and state-of-the-art applications related to vehicle-bridge interactions. It thus provides useful information for graduate students and researchers and therefore straddles the gap between theoretical research and practical applications.