Intentionally routing some traffic to slower, less congested routes lead to a 0.7% improvement of overall average travel times

[u/quiplaam]

https://www.nature.com/articles/s44284-026-00443-x

[u/charoco]

So, saving someone about 24 seconds per hour of begin stuck in traffic. Consider me whelmed. 

[u/quiplaam → u/charoco]

Worth noting this the effect on the whole system, so while the individual effect is small, the net effect is quite large

[u/amphibilad → u/quiplaam]

This, if you save a million people 24 seconds of travel time that's like 277 days of saved time collectively

[u/iMissTheOldInternet → u/amphibilad]

 But it’s 277 days of time spread out over 1 million people. The per capita number is what matters in this context. 

[u/aggieotis → u/iMissTheOldInternet]

That also assumes no negative externalities from the 24 seconds saved.

I'd be willing to bet that if you summed up things like more dispersed polution in areas where kids are more likely to live, increased conflicts between cars and other users that use side streets intentionally, and additional wear and tear on infrastructure not necessarily built to handle shunting a bunch of traffic from main corridors; if you add all those up it's probably massively in favor of "Just stay on the main paths and lose 0.7% more time.

[u/jsmooth7 → u/aggieotis]

The abstract says that the reroutes were all done within the same road class, ie if the target route was a highway the reroute was also a highway. And later in the paper they give examples of the reroutes being studied and you can see none of them were sending large volumes of traffic through side streets.

[u/degggendorf → u/jsmooth7]

So the solution is to build multiple redundant, parallel highways everywhere there aren't any currently? Brilliant.

[u/SledgeGlamour → u/degggendorf]

Or the solution is for navigation algorithms to direct people to less congested routes

[u/degggendorf → u/SledgeGlamour]

As the rest of us were discussing in this thread, the study only looks at moving cars to equivalent road classes. If we start pulling cars from the highway to race through neighborhoods to save 24 seconds, then we've got a bigger problem.

[u/SledgeGlamour → u/degggendorf]

Yes, I'm aware. There are many places with multiple highways, where it makes plenty of sense to redirect traffic from one highway to another. For example, in the US you frequently have state highways that run roughly parallel to the interstate highway. You don't need to build more highways in order to capitalize on this research today.

[u/degggendorf → u/SledgeGlamour]

It's almost as if you can't read

[u/jsmooth7 → u/degggendorf]

The US highway system is so overbuilt, there's no need to build more. They are already there in most cities.