Car Brake LEDs

I don't understand 2 things : why do you need a bypass resistor ? Why is there 2 voltage sources ?

1:The bypass resistor is there to tune the low brightness, so people can see you while driving. The momentary switch is representing your brake pedal, when depressed your LED goes into high brightness to let everyone know you're slowing down. 2: There are two sources on a 2009 Honda civic's brake bulb on each side, totaling four all together. This vehicle uses a dual filament bulb, One source for the low filament and a second source for the high filament both share a common ground . Hope that helps. 3: There are many different ways this can be setup. My goal was really simple and least amount of parts capable of safely doing the job.

I understood the break pedal switch. I didn't know that Honda Civic keeps light on low mode while running. When speaking about sources I meant voltage sources so I spoke about batteries :)

http://everycircuit.com/circuit/5754319197437952

updated schematic in the link above, that has a lot of improvements for inevitable failures that can happen.

This example is almost complete, except for the lamp that must be constantly lit in the circuit, and it would be better if you solved this problem by using small car lights, that is, when the pedal is pressed, this system is activated. And the desired lamp should be used through the small lights of the car and as a rear warning light