I imagine this code as a sandbox that mirrors how an actual 4‑way intersection would behave with sensors and V2X communication. In the simulation I use fixed positions for each stop sign and start position, but in reality I’d replace those constants with data from a LIDAR or camera pipeline: each vehicle’s GPS or relative pose is fed into a state machine that keeps track of which lane has a front‑car at the intersection. The logic in my `Car` class (approach, waiting, crossing, done) mirrors what a car would do once it receives a “go” signal from V2X. LIDAR gives me a 3D point cloud; I project each vehicle onto the road plane and compute its distance to the stop sign using vector subtraction (`dist = (stop_sign - pos).length()`). When the distance drops below a threshold, I set `state='waiting'` and start a timer (analogous to `STOP_WAIT_MS`). An ultrasonic sensor on the curb can double‑check that the car is truly at the stop line by measuring its range; if it confirms the position I keep the waiting state. V2X radio packets carry the direction, queue index, and “green” flag: when a vehicle receives a “green” message it changes to `crossing` and moves forward until it leaves the intersection rectangle (the code uses `intersection_rect.collidepoint`). The queue logic (`queues[d]`) is essentially a priority queue that my controller uses to decide which direction gets green next; I compute this by looking at the front car in each lane, checking its waiting time (`now - wait_start >= STOP_WAIT_MS`), and if all others are idle or already crossed, the controller broadcasts “green” via V2X. The math behind it—vector arithmetic for target positions, distance thresholds, and timing loops—remains unchanged; only the data sources change from hard‑coded coordinates to sensor outputs. Thus my code’s architecture could be a blueprint for integrating real‑world sensors: LIDAR for precise position, V2X for inter‑vehicle coordination, ultrasonic for proximity confirmation, all feeding into the same state machine that decides when each vehicle should move.