Highway Interchange

Lore & Background

The focus on realistic traffic mechanics stems from Colossal Order's background with the Cities in Motion series. When pitching the city simulation concept, publisher Paradox Interactive initially hesitated due to the market dominance of SimCity. This changed only after the critical failure of the 2013 SimCity game provided an opportunity for a competing franchise. The team aimed to create a system where citizens navigate roads based on the fastest available route, taking into account transit systems and road density. If a route is changed mid-transit, the simulated person is teleported back to their origin rather than recalculating from their current location. This logic ensures that visual traffic jams accurately reflect the efficiency of the player's design. The developers found that specific intersections, such as the single-point urban interchange or diverging diamond interchange, could be effectively modeled to demonstrate roadway efficiency.

In Their Own Story

The morning rush in a thriving district reveals the impact of road design on nearly a million unique citizens. As vehicles navigate the node-based graph created by the player's transportation system, they adhere to seven rules regulating behavior in traffic, such as slowing down on tight curves or adjusting speed along slopes. A well-placed interchange prevents the cascading problems that occur if players adjust roads in real-time while ignoring distant locations. The visual indication of congestion becomes an easy-to-comprehend sign of larger design flaws. When a commercial store increases its development level due to educated nearby residents, it relies on this efficient flow to hire more employees and generate tax revenue. Without these optimized connections, the city's economic growth stalls as traffic bleeds into residential zones, proving that the road system is fundamentally tied to the city's success.

Reader's Guide

To manage high-volume traffic flows, players must utilize the robust transportation system based on Colossal Order's previous work. Roads can be built straight or free-form, with the zoning grid adapting to the shape of adjacent roads rather than forcing a square plan. For major connections, players should employ variant road types like avenues with trees or highways with sound barriers to reduce noise pollution and increase property values. The game allows for various public transportation forms, including buses, taxis, trams, trains, ferries, and metro systems, which can be augmented along these routes. If the standard 25-tile limit restricts a player's vision, they can use Steam Workshop modifications to open all 81 tiles (324 square kilometres) of the map. Additionally, pre-packaged mods like 'Unlock All' allow players to bypass population tier unlocks and access complex road networks immediately.

Did You Know?

• The game engine was designed to simulate the daily routines of nearly a million unique citizens.
• If a citizen's route changes while they are in transit, they are teleported back to their origin instead of calculating a new path from their current location.
• Colossal Order used the market opportunity created by the critical failure of SimCity (2013) to greenlight development after initial rejections.
• The developers specifically tested the model on less common intersections like the single-point urban interchange and diverging diamond interchange to demonstrate efficiency.
• Players can use Steam Workshop modifications to expand the buildable area from 8 parcels up to the entire map of 81 tiles.