1. Overview

Living standards in Vietnam are continuously improving, becoming more affluent and modern. Consequently, the number of vehicles in traffic has increased significantly in both quality and quantity. However, alongside modern development, there persists a common habit among citizens of stopping in the wrong lanes or overstepping stop lines, particularly in major Vietnamese cities. This behavior negatively impacts the image of Vietnam in the eyes of international friends.

The project "Traffic Stop-Line Violation Warning System" aims to contribute to a more organized and civilized traffic environment in Vietnam. We hope this project will gradually instill better habits in people participating in traffic.

2. Current State of Research (Domestic and International)

Currently, there are many articles, projects, and initiatives aimed at building a better traffic culture. However, projects specifically focused on reminding commuters to stop at the correct designated road lines are very scarce, both domestically and internationally.

In Vietnam: As of 2013, the total length of the national road network exceeded 258,200 km. The number of motorcycles and mopeds alone grew rapidly from 21,721,282 units in 2007 to 33,906,433 units in 2013, and statistics suggest this number will continue to rise. Given the "high population density" situation, traffic education is currently limited to propaganda through banners, slogans, loudspeakers, television, and newspapers. There has not yet been a specific technical system dedicated to warning vehicles about stopping in the wrong lanes.

Internationally: Due to differences in infrastructure and transportation modes compared to Vietnam, there have been no documented projects or works addressing this specific issue to date.

3. Hardware Block Diagram

Figure 1. System Block Diagram

• Ultrasonic Sensor: Responsible for detecting vehicles stopping in the wrong lane and sending signals to the control circuit for processing.

• Control Circuit: Receives signals from the ultrasonic sensor to manage other circuits within the system.

• Audio Circuit: Receives signals from the control circuit and plays a recorded voice reminder.

• Power Supply Circuit: Provides electricity to the entire system.

• Traffic Light Model: Simulates the traffic signal state.

4. Algorithm Flowchart

Figure 2. Algorithm Flowchart

• Explanation:

  When the red light is on, the control circuit activates the Trigger pin. While the red light is active, if the Echo pin returns a signal that remains consistent across three consecutive measurements, the MSP430G2553 microcontroller will trigger the audio circuit to play the reminder. Conversely, the system will check if the red light is still on and repeat the process.

To distinguish between a pedestrian crossing the line and a motorist stopping incorrectly, the project employs a specific method: verifying the Echo pin values over three measurements. If the distance recorded in these three instances is identical or within an allowable tolerance (the difference between the 3rd and 1st measurement is less than 3cm on the model), the system concludes that a vehicle is improperly stopped and issues a reminder. If the three measurements vary significantly, the reminder is suppressed.

• Distinguishing between individual and group pedestrians:

  At traffic signals in Vietnam, the majority of pedestrians use the designated crosswalks. In cases where a group of pedestrians walks outside the crosswalk, the sensor relies on the measured distance. Since the interval between moving people varies, it is rare for three consecutive measurements to capture identical distances (as people do not step perfectly in sync relative to the sensor). Therefore, the probability of the ultrasonic sensor triggering a false alarm for pedestrians is extremely low.