A hazard sign is performed by turning on both side of turn signal light in the same time. This type of sign is usually availabe in car but not in motor cycle. But, if you want your motor cycle has this kind of sign, then you can add this circuit to your motor cycle.
This is how this circuit works:
When the switch of turn signal is turned on for right sign, there is an electric current flow through D1 then to C1 and to R1 when the flasher blinking. Electric current from resistor R1 used to activate transistor TR1. When the flasher light, C1 will be charged, so when the flasher turned off, there is an electric charge inside C1 to keep remain TR1 on.
If the switch is used to turn the right sing light in usual way, then there is no difference in how turn signal light lit, it is only the right side light lit. But it the switch is switched to turn left sign, then when the flasher lit, TR2 is also activated by the current flow through R2. If the swaping switch is quick enough, then at that time TR1 is still active because the charge inside C1 is not yet empty. So, relay will turned on, and because this relay is used to paralleling the right sign switch, then the right light is also lit. This will also recharge C1 so that R1 will be kept active as long as turn signal switch is still turn left position.
If then the switch is turned off, so TR2 will also off, and relay will off too, so there will no recharge for C1, then TR1 will also off.