Convert video to timelapse

Hi,
I've searched but haven't found this specific question:
I have around 30 min. of 30fps video (dashboard cam style) that I want to shrink to around 15 sec.
Is there a way to do so apart from increasing the clip to ludicrous speed?
I was wondering if I there is a an automatic way to substract frames to reduce the size of the files, basically making a timelapse out of 30fps?

And yes, I know I should have just done a timelapse instead.

I would simply change the clip playback speed to something much faster. E.g. 4000pct or more.

I'm not sure what you are expecting from a timelapse. If you shot video, not time delayed stills, than "increasing the clip to ludicrous speed?" is pretty much the only way to make a timelapse. That's is what a timelapse is...condensing a long period of time into a short period of time, by increasing the playback speed.

The issue with just increase the speed is that you will have the shutter at 1/48th or thereabouts: if you want to also increase the perceived exposure time, i think you can:
Increase the speed to the stupid number
Set the motion blur to bigger numbers. That will blend multiple images together as if you had something like 1 sec exposure

If you want to get stupid, add a very very very little flicker to it and might be a little, very little camera jitter.

Just a thought.

(Did not try myself, going from intuition)