An application note from Richtek on buck converter used in automotive application. Link here (PDF)
Automotive environment can be quite harsh and designing electronics that need to work reliable in this environment takes special care, and often requires automotive qualified parts.
When designing voltage regulators that need to step down an intermediate voltage from the car battery supply, the car battery voltage fluctuation needs to be taken into regard.
The full operating temperature range needs to be considered for all aspects of the design, and all component parameters have to be checked over temperature.
The car radio receiver is nearby, which means that any switch-mode converter radiated emission needs to be minimized to avoid switch noise being coupled into the car radio receiver.