Keep a Strong and Reliable Bluetooth Connection to Provide Prompt Alerts for Unattended Children Left in Car Seats.

NHTSA Tested Seven Different Types of Driver Alert Systems for Unattended Children.

Date Posted

Testing of Unattended Child Reminder Systems

Summary Information

New systems and technologies have been invented to prevent caregivers from leaving children unattended in a vehicle. These systems can alert caregivers with displays or give audio alerts. In the summer of 2020 seven different types of original equipment manufacturer (OEM) systems were tested to assess if each technology successfully reminded caregivers and functioned as designed. 

These systems included: 

  1. The child restraints system (CRS) chest clip system - consisted of a clip sensor and a wireless receiver connected to the on-board diagnostic (OBD) port.
  2. Global Positioning System Smartphone Application - reminder feature enabled in the smartphone.
  3. Pressure Sensor – consisted of a pressure sensor pad, driver seat belt clip, and a cigarette (CIG) lighter display.
  4. Temperature Monitor – clip attached to child and paired to a smartphone which read temperature.
  5. Radar based - sensing system equipped into vehicles under development by suppliers.
  6. Rear door logic - detected an unattended occupant in the rear seat by sensing rear doors being opened within a specified time of the vehicle being turned off.
  7. Rear-Door Logic and Ultrasonic System – used both the rear door logic and an ultrasonic sensor to detect whether the rear seat was occupied. All the technologies were tested in this study with the use of an infant baby doll except for the ultrasonic system.

Lessons Learned

The following lessons learned summarize the findings from testing the seven types of systems for the unattended driver reminder systems.

  • Keep a strong and reliable Bluetooth connection. The reliability of radio and Bluetooth connectivity is dependent on the area and the possible interference from nearby radio sources. Since this study was conducted outdoors with the use of smartphones, a strong and reliable Bluetooth connection was needed for the smartphone applications. Strong connection would provide prompt alerts for unattended children in the car seat.
  • Check whether all scenarios in the rear-door logic systems effectively warn if an occupant is still in the vehicle. It was found in this study that the system could not detect the occupant and provide warnings to the driver in certain scenarios. Since the rear-door logic was based on a sequence of door openings, it did not consider a child being in the front seat.
  • Monitor whether the smartphone applications alert the caregiver if the application is not running. It was found that if the phone was turned on, but the application was not running, the caregiver would not receive an alert.
  • Consider the limitations of the rear-door logic and the CRS clip systems. The systems were only able to activate when the vehicle reached a speed of at least five miles per hour. For the rear door logic and ultrasonic system, the doors must all be locked for the sensor to activate. However, the rear-door logic functioned when the doors were left unlocked (without the combination of the ultrasonic sensor).
System Engineering Elements

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