Vehicle interaction with zeds

[Max N]

Hello fellow mod gods/zomboid god devs.

I have a little question regarding vehicle scripts/events that affects behaviour when vehicle stumbles a zed.
Basically, i want to to tweak some numbers on a logic that decreases speed whenever we crush into zed - i have traversed through lots of files and found everything but logic that handles the speed change on zed hit.

Example of what i am trying to achieve - so currently if i am riding 60mph on a heavy-duty jeep car and hit zed, so my speed drops to 30mph or lower (so at this point we have lost 30mph), but i want to tweak those logic, so my speed drops only to 50mph (so we have lost only 10mph there).

Is that possible? if yes, where i should look for? 

Thanks a lot for the answer