[mike-the-mikado]

Interesting - I have believed for many years that it was around 17 MPH. I felt that this tallied with my observations - as traffic levels increase, vehicles slow down (increasing total capacity) until it falls to a critical speed (when slowing down reduces capacity) and then it changes to stop/go.

In my experience (on UK roads) this critical speed is around 17 MPH - but it might be a little different elsewhere.

[namibj]

Freeway capacity chokes at the limit giving rise to basically overpacked lanes slumping from metastability; systemic control with ramp meters or I66 (within the Washington D.C. Metro area) style real-time dynamic pricing lets freeways flow properly around peak capacity if properly implemented.

There are roads that regularly suffer from acutely insufficient capacity in many metro areas; specifically, repeatedly at times _the dynamic pricing toll that would discourage enough people from using it to stay uncongested_ would overshadow the price of a rental-with-driver (Uber-style) during off-peak times. It's not that the people shouldn't get through; it's that most people won't need more than a backpack worth of luggage with them and could thus be packed 3~4 passengers for each driver. Splitting the toll would be the reason to do so.

Unfortunately only really dynamic congestion tolls would really fix the concept of rush hour traffic jams. And the necessary surveillance system would bring severe mass surveillance/tracking concerns with it at least in central Europe.

[rangestransform]

I don’t think the surveillance needs to be cameras, a combination of radars (for velocity) and induction loops or the axle-counting rubber hoses (for counting) should do the trick

[namibj]

The problem is less from the full coverage measurements of congestion this scheme would need, and more due to the billing of almost all vehicles on almost all roads which could be used for bypassing major roads when driving congestion-relevant commutes. So main thoroughfares/arteries, pretty much anything you'd visually classify as "highway" (unless it's a dead-end), and Autobahn/Interstate.

Without cameras: How do you do the billing then? Like, what else other than ALPR or the privacy-basically-equivalent RFID tag/token stuck to the windscreen (and correlated with a camera or similar to catch vehicles with inoperable RFID tags)?

If you'd cover old-built urban cores, you could further punish the driving-in-circles tactic of avoiding multi-story parking garages that hopes to either find a surface spot during their brief empty lifetime, or even to stall until a former passenger has ran an errand and can be picked up again.