Pat Kerr, a programmer who worked on the vehicle system for the original Grand Theft Auto, has released a playable driving physics demo. He recreated the prototype concepts from nearly 30 years ago using JavaScript and gave the visuals a moderate update.
Obbe Vermeij, a former Rockstar employee, recalled that the driving experience in the early stages of the original game's development was poor. Kerr, who was not yet part of the project team at the time, added some driving code that improved car handling. Vermeij believes the feel of the new demo is still very similar to the original game, especially the handbrake effect. These early development details come from the memories of those involved.
Kerr stated that he wrote the 2D physics simulation over a weekend in late August 1996, which later became the foundation for the game's vehicle system. Its core used 2D rigid body dynamics to handle rotation and torque, followed by the addition of a vehicle system simulating tire behavior. Kerr admitted that the latter did not fully adhere to real-world physics but met the design needs of the time.
The demo also includes visual markers to showcase vehicle movement and changes in tire grip. Kerr specifically noted that he created this demo independently, with no affiliation to Rockstar, Take-Two, or the official Grand Theft Auto projects.