In general I'm opposed to using traffic cams to ticket people who don't stop at lights or intersections, but I think I'd allow it in this instance.

Also, only like 50% of cars stop for those stop signs!

edit: damn it! I typed and submitted the comment RIGHT BEFORE he said it in the video!

Well, the video already mentioned the cost of getting traffic lights as well as laying down miles (or Kilometres) of electric cables, so this is a rural area (otherwise a city/town would've certainly found the money to do it)... installing traffic cams will need to lay those same cables.

They could do a roundabout maybe? UK & EU are fond of those...

Solar powered traffic cams with, you know, internets and stuff?
Or kickstarter the 100k and stagger the junction right now.

or... put a 4-way stop, where the main road (and cyclists in danger) would have to stop as well.

Or create a new sign "Cyclists, look left for arseholes"

Even if you don't put a 4-way stop, could certainly have a solar-powered (battery at night) LED "flasher" on the stop signs that would blink when detects movement on main road. A raspberry-pi has enough cpu power. Might cost $20k to install a pole to mount 2 cameras and solar panel(s). This "blinking stop sign" would be so rare, that it would catch drivers attention and they'll be more likely to stop.
(I'm not suggesting raspberry pi are reliable enough for this application, but my point is the computer vision can be done in < 10W, which can easily be handled by a solar panel, even in England)

I would thing a strategically placed, fairly large mirror would correct a fair amount of the problem. Suppose that starts getting into "too expensive" territory pretty quickly though, with inevitable vandalism and whatnot.