What resistor values are needed for wiring LED taillights with a SPDT relay?

[RamSST]

Hi. New here. I'm not necessarily a newb at wiring I've used solder before and have wired up other simple wiring diagrams. I'm hoping someone can help me with a task I'm looking at doing. I'd like to wire up a set of LED taillights. 48 red led's in the brake circuit and about 24 in the turn signal circuit. The brake light will require a SPDT relay to switch from being illuminated and braking. I have a diagram but have no idea what kind of resistor values I will need. It's a 12V system. Any help is much appreciated
These are the specs on the red LED's I have:
Specifications:

Material: InGaN
Emitting Colour: Red
Lens Type: Water clear
Reverse Voltage: 5.0 V
DC Forward Voltage: Typical: 1.9 V Max: 2.3 V
Wave Length: 625-635nm
Luminous Intensity: Typ: 15,000 mcd
DC Forward Current: 20mA
Viewing Angle: 20±5degree
Lead Soldering Temp: 260oC for 5 seconds
Intensely Bright

This is the wiring diagram I intend to use:

 

[Emicro]

The problem that you are going to have with someone responding to your request, is that you are messing with a safety system on a vehicle. There is not only a liability issues, but also a moral issues. If you want to do the math yourself it is very straight forward. What you are trying to do is all covered in ohms law. You can use the resistors as current limiting devices, so you only have to worry about the voltage drop across the resistors you are going to be designing with. Also another thing to consider is the safety where your circuit will be located. Will it get wet? Will it get dirty? Will it be able to withstand the physical jarring of normal vehicle travel?