Designing a Smart Traffic Light Control System

Suppose you are working in an engineering department for a city and your team is tasked with upgrading the city’s traffic infrastructure. The system to be implemented uses smart sensors to detect vehicles and pedestrians, and control the lights using combinatorial logic and Boolean functions.

The system inputs are vehicle detected at intersection ([latex]V[/latex]), pedestrian waiting to cross ([latex]P[/latex]), timer expired (i.e., minimum green light duration met ([latex]T[/latex])), and emergency vehicle detected ([latex]E[/latex]).

The system outputs are green light for vehicles ([latex]G[/latex]), a walk signal for pedestrians ([latex]W[/latex]), and a red light for vehicles ([latex]R[/latex]).

Define the following logic conditions:

1. Vehicles get a green light if a vehicle is detected, no pedestrian is waiting, and the timer has expired.
2. Pedestrians get a walk signal if a pedestrian is waiting and no emergency vehicle is detected.
3. A red light is shown if an emergency vehicle is detected or if the walk signal is active.

Task 1

Write the Boolean expressions for each of these logic conditions.

Task 2

Create truth tables for each output based on all combinations of inputs. This helps verify the logic and ensure no conflicting signals are given.

Task 3

Design a combinatorial circuit using AND, OR, and NOT gates to implement the Boolean functions. Minimize the number of gates using Boolean algebra simplification.

Task 4

Describe three real-world considerations for this smart traffic light control system.