How Pizza Tycoon simulated traffic on a 25 MHz CPU

Context I've been working on Pizza Legacy, an open-source reimplementation of the 1994 DOS game Pizza Tycoon. The game has a close-zoom street view of the cities, and when you scroll around it you can see a steady stream of cars driving through the streets. Maybe 20 or 30 tiny sprites at a time, but they navigate the road network, queue behind each other at intersections, and generally look like a living city. Yes, it was a bit buggy because sometimes they would drive through each other, but it.