short circuit on the output of a linear voltage regulator
For load-dump info, I suspect that ISO 7637-2 and ISO 16750-2 are two documents you may want to consider.

For protection, as well as distributing the dissipation load, perhaps something along these lines?







simulate this circuit &ndash; Schematic created using CircuitLab

The above is more a concept than a crafted design. I just picked one possible series of TVS you might use. There are others, of course. And I didn't point out which voltage to use there. I'd probably recommend that you examine the details of the 78L33's maximum input specification and find a TVS voltage that keeps you comfortable. I added a couple of small caps, too.

The zener pre-regulator section was just pasted in, from memory. I picked 6.2 V because that seems high enough to satisfy the dropout of your regulator and it will distribute some of the dissipation onto \$R_1\$ and \$R_2\$. I chose two resistors there for two reasons -- (1) if one opens then the other is still there and (2) also for dissipation, in case it matters. You could further complicate that by arranging things so that if a screwdriver shorts one out there is still more, by adding a series resistor, too. Up to you.

The exact values of those two resistors does matter. I picked ones that set up about \$50\:\textrm{mA}\$ each, for a total of \$100\:\textrm{mA}\$. However, the zener I selected is only tested at most for about \$40\:\textrm{mA}\$. So again, you need to think this through on your own end. You may need to set up an added dummy load (and/or add a BJT emitter follower for it after first selecting a 6.8 V zener.) Again, this is conceptual and you need to think it through on your own. I just wanted to call your attention to the idea of adding this kind of section.

The PI filter is mostly for RF. I'm not sure if it is needed and I also don't know how the 78L33 will handle the preceding PI. But it is there to make you at least think about the subject, in case it matters to you.

Finally, your 78L33. You might also consider adding a PNP BJT bypass around it, too.

So:


Input protection section for load dump events.
Possible pre-regulation section.
Possible filter for RF.
Linear regulator, with an optional PNP BJT bypass.


You can pick and choose. But consider including the TVS protection and perhaps the PNP BJT bypass to shift some dissipation away from the TO-92 regulator.