ESP32 Traffic Light Controller PCB (24/7, Relays, Watchdog, Failsafe)

I need an experienced electronics/PCB engineer to design a reliable, 24/7-operating traffic light controller PCB.
This is a safety-critical system (not a hobby project).

SYSTEM:
• MCU: ESP32
• Load: 220VAC traffic light LED modules
• Outputs: ~19 relay-controlled channels
• Operation: Continuous (24/7)

RELAY CONTROL:
• Relay outputs driven via 74HC595 shift registers (SPI-style)
• 3 × 74HC595 chained
• OE pin must have hardware pull-up (outputs OFF at boot)
• ESP32 enables outputs only after startup
• Relay drivers with proper flyback protection

FAILSAFE / SAFETY:
• Master relay/contactor that cuts power to ALL lamp outputs
• Must drop on:
- ESP32 crash
- Watchdog timeout
- Power instability
• Safe power-up and fail behavior is mandatory

fuse.

WATCHDOG & RESET:
• External hardware watchdog + reset supervisor
• ESP32 provides heartbeat signal
• Watchdog disables outputs and drops master relay on failure
• Do not rely only on ESP32 internal watchdog

LAMP FAILURE DETECTION:
• Detect CURRENT flow
• Group-level detection is acceptable


POWER:
• Input: 12V DC

PCB & SAFETY:
• Proper 220VAC clearance/creepage
• Clear separation of HV and LV sections


WHO SHOULD APPLY:
• Experience with ESP32 hardware
• Experience with AC mains / industrial electronics
• Comfortable designing fail-safe systems
• easy eda