If you plan on actually putting this in a vehicle I suggest your group goes through the following. Automotive electronics is very nasty.
There is a good app note AN2689 by ST on automotive electronics. reading it will help you a lot.
https://www.st.com/resource/en/application_note/cd00181783-protection-of-automotive-electronics-from-electrical-hazards-guidelines-for-design-and-component-selection-stmicroelectronics.pdf
Also take a look at this: Distilled Automotive Electronics Design | Analog Devices and then there is this one.
Transient Voltage Suppression in Automotive Applications