It is perfectly logic to not specify the LED manufacturer the voltage where the led will consume 200mA. You have to make the current limiting with a proper circuit. The voltage is relevant to that circuit. One may design a pulsed current source that needs 20 volts to produce 200mA flow and another designer a better circuit that can work on 5 Volts. The LED has to be limited to 200mA and the voltage at its leeds will be managed by itself (I bet it wont be more than 3,5 Volts).

By pulsing you will not gain in brightness more than DC driving. The total dissipation of the LED should be the same in any circumstance. You can just vary the brightness. So you can simulate the normal red tail light and STOP light.

Ioannis