Gran Turismo 4 was originally planned for a 2003 release but was delayed by over a year and a half during development. Its promised online multiplayer mode was removed before launch, a decision that drew considerable criticism given how prominently online features had been marketed. A limited online test version was later distributed to approximately 5,000 selected players in Japan and South Korea in 2006 to evaluate infrastructure intended for Gran Turismo 5, with public online service running from June 1 to September 1, 2006. A separate public beta was held for North American PlayStation Gamer Advisory Panel members during the same period.
Gran Turismo 4 expanded the series' car and track roster substantially. The game features 721 cars from 80 manufacturers spanning production years from the 1886 Daimler Motor Carriage to 2022 concept vehicles. Fifty-one tracks are available, with many being new circuits or revised versions of existing Gran Turismo locations. Notable real-world additions included circuits not previously present in the series.
The primary driving mode, A-Spec, awards points up to a maximum of 200 per race event based on how outmatched the player's car is relative to the AI competition. Points from a given event can be improved by re-entering the race with a less advantaged car. Thirty-four Driving Missions each award 250 points and structure specific challenges such as overtaking within a set distance, managing slipstream drafting against identical opponents, or recovering from a time penalty within a single lap.
B-Spec mode, new to the series, places the player in the role of a racing director rather than a driver. The player issues instructions about aggression level and pit timing to an AI driver while monitoring tire wear and fuel consumption. Race time can be accelerated up to three times normal speed, making endurance events feasible within a single session. B-Spec unlocks harder events as the AI driver's skill improves across three categories.
Photo Mode allowed players to position a virtual camera at trackside locations including the Grand Canyon and capture screenshots at resolutions up to 1280x960.
Physics improvements over Gran Turismo 3 included body pitch and roll during braking, more accurate weight transfer behavior, and barrier friction tuned to reduce the effectiveness of wall-riding shortcuts. Graphical fidelity improved significantly from its predecessor despite running on identical PlayStation 2 hardware.
Gran Turismo 4 received generally favorable critical response. Its physics model, car roster, and visual presentation were highlighted as strengths. Recurring criticisms included AI opponents that drove preset lines without acknowledging the player's position, the absence of online play that had been promised during development, and the inability to inflict rendered crash damage on vehicles.
Jeremy Clarkson of Top Gear conducted a real-versus-game comparison at Laguna Seca, finding the simulation's lap times faster than achievable in real life due to the absence of mechanical risk and driver feedback. Automotive journalist Karl Brauer conducted a similar structured comparison with professional racing driver A.J. Allmendinger, reaching parallel conclusions about the gap between in-game performance and real-track results.
The game received the E3 2003 Game Critics Award for Best Racing Game during its preview cycle and was ranked among the top PlayStation 2 games by IGN.
Gran Turismo 4 sold over one million units in Japan by February 2005 and exceeded six million worldwide by March 2005. Final shipped figures reached 1.27 million in Japan, 3.47 million in North America, 6.83 million in Europe, and 180,000 in Asia. It received a Double Platinum award from the Entertainment and Leisure Software Publishers Association for exceeding 600,000 UK sales. It ranks as the third highest-selling Gran Turismo game, trailing only Gran Turismo 5 and Gran Turismo 3: A-Spec.
Gran Turismo 4 served as a technical and content bridge between the PlayStation 2 generation and the forthcoming PlayStation 3 era. Its B-Spec director mode represented an experiment in passive racing engagement that did not carry into subsequent series entries. The game's Photo Mode established a precedent for in-game photography tools that became a recurring feature across later Gran Turismo titles. The accompanying Chinese, Japanese, and South Korean releases were bundled with a 212-page driving guide, reflecting the franchise's positioning as an educational racing resource alongside an entertainment product.