ZCars is an open-source vehicle physics project focused on realistic ground vehicle simulation.
It is currently in development, but will be released for Garry’s Mod and s&box in the future.

Follow the development in our Discord community:
 https://discord.gg/tHSkbBJzxG

Features:

• Drivetrain system that simulates interaction between drivetrain components and distributes torque between them using an impulse-based physical model. 
• Suspension kinematics system that calculates the position of the suspension and wheel hub, allowing simulation of arbitrary mounting geometry and dynamic adjustment of camber, toe, and hub position based on suspension travel and steering angle.
• Tire physics model using a multi-raycast approach, simulating tire behavior as interaction between bristles and the surface, with force distribution across the contact patch, accounting for vertical load and grip limits through a friction ellipse. 
• Transient tire dynamics simulation, allowing realistic delay in tire response and loss of traction. 
• And much more.