I own an early full-size PHEV that has no noisemaker. It is a surprisingly large sedan that, even today, people are surprised to discover gliding silently on th

I own an early full-size PHEV that has no noisemaker. It is a surprisingly large sedan that, even today, people are surprised to discover gliding silently on the road behind them. I cannot tell you how many times, while being fully alert and creeping at low and safe speeds that people walking in the middle of the road or in a garage have suddenly become shocked - SHOCKED - that there had been a full-size sedan rolling silently behind them. My other option is honking, which will startle them - perhaps, to their death.