System Architecture of Safety: Failsafes, Feedback, and the Human-Machine Interface in Towing

Towing a vehicle is an exercise in risk management. A mechanical failure in the hitch, a loss of electrical signal, or a separation event can turn a towed car into an uncontrolled projectile. Safety systems like the Roadmaster InvisiBrake are designed not just to stop the car during normal driving, but to handle catastrophic failure modes.

This article explores the “Architecture of Safety.” We will analyze the Breakaway Logic, the Closed-Loop Feedback provided to the driver, and the engineering required to prevent False Activations (brakes dragging). It is an investigation into the failsafes that keep the highway safe.

The Breakaway Protocol: The Ultimate Failsafe

The nightmare scenario for any RVer is the tow bar failing, sending the car careening down the highway. The Breakaway System is the last line of defense. * The Physical Link: A steel cable connects the RV frame to a switch on the front of the car. This cable is shorter than the safety chains. * The Logic: If the tow bar fails, the car drifts back. The cable pulls a pin from the Breakaway Switch. * The Circuit: This switch closes a direct circuit between the car’s battery and the InvisiBrake’s compressor. It bypasses all other logic (brake lights, ignition status). The compressor runs to maximum pressure (80 psi), locking the car’s brakes instantly. This converts the car’s kinetic energy into heat (tire friction and brake friction), bringing it to a halt before it can cause massive damage.

The Feedback Loop: The Monitor LED

A hidden braking system presents a danger: How do you know it’s working? Or worse, how do you know it’s not stuck on? * Dragging Brakes: If the system malfunctions or the pedal binds, the brakes could drag for miles, overheating the rotors, boiling the fluid, and catching fire. * The Feedback Wire: The InvisiBrake includes a monitor wire that runs from the car back to the RV dashboard. It connects to an LED. * The Signal Source: Crucially, this signal comes from the Cold Side of the Brake Switch in the car. It does not indicate that the compressor is running; it indicates that the pedal is physically depressed. This is True State Feedback. It confirms that the mechanical action has occurred.

Audio Alerts: The “Panic” Mode

The system also includes an audible alarm in the RV. * Extended Braking Logic: If the brakes are applied continuously for more than 15-20 seconds (e.g., resting a foot on the pedal, or a malfunction), the alarm sounds. This warns the driver of a potential “drag” situation, preventing thermal destruction of the braking system.

False Positive Mitigation: The Logic of Activation

The InvisiBrake must distinguish between “Braking” and “Blinkers.” * Combined Lighting Systems: On many RVs, the brake light and turn signal share the same wire (bright filament). * Pulse Logic: If the system simply looked for voltage on the wire, a turn signal (pulsing voltage) might trigger the brakes on and off repeatedly (“pumping”). * The Filter: The controller logic filters the input signal. It looks for a steady voltage (braking) versus a pulsed voltage (turning). This ensures that signaling a lane change doesn’t jerk the towed vehicle.

Conclusion: The Invisible Co-Pilot

The Roadmaster InvisiBrake is a study in systems integration. It weaves itself into the electrical, pneumatic, and mechanical fabric of the vehicle.
Its value lies in its autonomy. Once installed, it requires no setup, no box to move, no adjustments. It simply waits for the signal—from the brake lights or the breakaway switch—to execute its programming. For the user, the complexity of installation is the price paid for the simplicity of operation and the assurance of safety protocols that react faster than humanly possible.