AutoBlinkers Lite v1.1 by heartgg
https://www.gta5-mods.com/scripts/auto-blinkers-lite

[Features]
Manually switch your blinkers on and off
Automatically turn off your blinkers.
Manually switch your hazard lights on and off.
Automatic brake lights when you are stopped.
Expect little to no performance loss from this mod (hence Lite)

[How to use (with default key binds)]
Press Shift and a turn key (A or D) to turn on the respective blinker.
Press T to manually turn off all blinkers.
Press X to turn on hazard lights (and turn them off with T).

[How to install the mod]
Download ScriptHookV. Open "bin" and drag dinput8.dll and ScriptHookV.dll to your GTA main game directory. Create a "scripts" folder in your main game directory as well (without the quotation marks of course).
Download ScriptHookVDotNet. Drag ScriptHookVDotNet2.dll, ScriptHookVDotNet.ini, and ScriptHookVDotNet.asi to your GTA main game directory.
Download this mod and place the autoBlinkersLite.dll and autoBlinkersLite.ini into your "scripts" folder.
Edit the ini file to your liking (I strongly recommend using Shift and Turn keys to turn signals on.)

[INI Stuff]
brakeLightOffSpeed is a setting to check what your speed is to turn on the brake lights. For instance, if its set to default (0.5), then the brake lights will turn on when your GTA speed is below 0.5. 
