What is the primary difference between the Type 179 and 170 controllers?

Answer: B — Microprocessor used

The primary difference between the Type 179 and 170 traffic signal controllers lies in the microprocessor used. The Type 170 controller utilizes a less sophisticated microprocessor compared to the Type 179, which generally has enhanced processing capabilities. This difference in microprocessor technology means that the Type 179 can handle more complex traffic signal operations and programming, allowing for features like improved timings and better management of traffic flow. The Type 170 controllers, while still effective, are often limited in terms of advanced functions and adaptability compared to the Type 179. This distinction is crucial for understanding the evolution of traffic control technology and how advancements in microprocessor design can significantly impact signal performance and management.