Traffic Giant is a simulation computer game wherein the player is tasked to build a transport system. Set during the 1850's the player develops a transport system for an entire country. This is done while at the same time gaining a fair share of profit from transport passengers and freight. As a simulation game, the transport system is managed over time until it evolves to what it is in the modern world. The game covers a variety of transportation forms depending on the era. For example, horse carts in the 1850s and modern trains in the 90s. The game world is rendered in isometric view, allowing the player to see the environment from above. Most of the main functions are displayed on the left side of the screen as icons. The player's profit is displayed on the bottom portion of the screen. This profit can be used to upgrade the entire transport system, from repairing railways to building roads and highways.
Transport Giant features a variety of factors that may affect the profitability of the transport system. Examples are season changes and the country's economic stability. When the economy is achieving growth, more in-game citizens may buy cars instead of using public transportation vehicles such as trains and buses.