Something I've always wondered is how people actually do the backwards alphabet test. I don't think I could efficiently do it sober, but I do have an O(n^2) algorithm for doing it; sing the ABCs in your head, and only say the letter before the one you've already said.

So like, abcdefghijklmnopqrstuvwxyZ, abcdefghijklmnopqrstuvwxY, ...

You can also use this algorithm to reverse a linked list, though you will not get the job if you do. I'm wondering if the cops are as picky as Google interviewers.

A few years back for fun, I learned to say the alphabet backwards as quickly as I could. I used basically the same technique I use as a musician to learn complex phrases; start with a short sequence (like "z y x w") and repeat it over as slowly as you need, and increase the speed as you get better at it, then either extend it a few more letters (e.g. "z y x w v u t") using the same strategy or learn the sequence starting with the next letter separately ("v u t s r q") and then "glue" them together when you're proficient with both. It took me only a few minutes of practice to get the whole alphabet this way, and it's stuck fairly well despite not really ever practicing it other than to occasionally show people as a party trick. Strangely, the letters seem to work better in that order for me; I can actually say the alphabet faster backwards rather than forwards, although it's hard for me to to tell if that's actually due to the sounds blending better objectively or due to the fact that I tend to have a bit of trouble with enunciating clearly in general and the "backwards" route skipping some learned bad habits that the forwards route uses.

Since I don't drink any alcohol and don't drive, I can't imagine I'd ever have a chance to use this in a field sobriety test, but I also suspect that a cop who pulled me over wouldn't find it particularly amusing, so I wouldn't be eager to try it anyways.

I’ve always assumed a gotcha here is when the driver says “officer, I don’t think I could do this sober” and now they’ve admitted guilt.

Look up the field sobriety test Steve Martin does in LA Story - hilarious

Is this online anywhere? I took a look but couldn't find a snippet on youtube.

Funny you mention that since the first time I heard them sung backwards involved a field sobriety test that the driver passed.

I decided that it was a useful skill. Later when our kids were born and the long early morning hours were filled with rocking chairs noises, diaper changes, feeding and burping I took the opportunity to add that version to my song list. Sometimes I ended up singing every song that I knew any words from so it helped a lot when I was tired to focus on one tune.