The power of collaboration: How we can reduce traffic congestion

> For this study, the Google Maps algorithm was modified to prefer alternative routes with similar travel times and segment types, effectively guiding trips away from the pre-selected congested segments

> Over a six month period, we adopted a city-wide switchback (also known as crossover) experimental design, alternating between this treatment and the control (unaltered) routing algorithm over consecutive days to appropriately measure the effect of this intervention

> Averaged across cities, we observe a median increase of around 2% in driving speeds on targeted segments, corresponding to a median decrease of 0.5% to 1.0% in fuel consumption rates

The cities were: Atlanta, Boston, Chicago, Los Angeles, Miami, New York, Philadelphia, Salt Lake City, San Francisco, Seattle.

The data and code is also available (https://github.com/google-research/google-research/blob/mast...) from the paper (https://www.nature.com/articles/s44284-026-00443-x).

Kudos Google! Nice to see this kind of work. That said, let's just build more trains?

Why cant we have smart stop lights. Nothing more annoying than sitting on a street with nobody coming and a red light for some arbitrary time period that's totally incorrect for the time period I'm currently in

One of the things this type of intervention doesn't take into account is that different roads are built with different levels of hardiness based on the amount of traffic they are expected to receive.

For instance, a few years ago, a segment of I-495 in Delaware needed to be unexpectedly shut down for emergency repairs. Drivers were rerouted. But because of the increase in traffic on the less-hardy detour route, that route needed repairs and repaving soon afterward, much more quickly than it would have ordinarily required.

So yes, drivers can be better dispersed to ease congestion, but we also need to consider the secondary effects to the roadways themselves.

Traffic apps only know about congestion if someone running the app goes down the congested road. Because of this, I've always suspected that the apps, from time to time, will route someone down a route they haven't gathered data on in a while, just to collect the data, and even if the route is likely to be suboptimal.

If we could copy the traffic laws of a country like Germany to the US, I think that would have the biggest + cheapest effect. I am OK with automated/elevated enforcement if it means stop & go traffic evaporates into free flowing conditions.

We should also take the idea from Finland where the traffic fines scale with each person's ability to pay. $100 for camping the passing lane or failing to maintain a reasonable following distance is not a big consequence for a lot of people. $100k covers the edges a lot better.

https://www.theguardian.com/world/2023/jun/06/finnish-busine...

When Google Maps routes me using a smaller secondary road instead of the main road that I would otherwise have used , I've always wondered whether that significantly changes the amount of traffic that smaller road sees. It's funny to consider that arbitrary black-box changes to the routing algorithm can have a noticeable effect to people that live there.

Interesting, I always just assumed they were already doing this.

>During “treatment” days, the modified routing guided all trips that encountered the pre-selected congested segments toward alternative routes with similar travel times.

Why would they specifically need to route people away from congested segments? Presumably if a segment gets congested enough, it'd be considered slower and therefore won't get picked in the first place?

Where isn't there traffic congestion?

Hey I patented this idea about a decade ago:

https://patents.google.com/patent/US20170184409A1

(I'm not saying I'm the first or only person to think of it, but I did patent it, as well as the extra claim of compensating those people sent on the slower route).

For over a decade, I imagined that if I ever landed a job at Google, this would be my most significant project. It made me chuckle a bit when I read the announcement, they finally built it! confirming that my thoughts weren’t entirely delusional XD

The way to maximise traffic congestion would be to remove trucks off the road during peak times, banning trucks from the fast lane at all times, making it the social norm to toot someone in the fast lane so they move over.