Vehicular accident reconstructions are often conducted to answer questions about automobile accidents that may arise in lawsuits. Forensic engineers are frequently employed to conduct in-depth collision analysis and reconstruction to identify the collision causation and contributing factors in different types of collisions, including the role of the driver(s), vehicle(s), roadway and the environment. The laws of physics and engineering principles such as the conservation of linear momentum, work-energy methods, and kinematics are the basis for these analyses, and the engineer may make use of software to calculate useful quantities.