51–60 of 174 posts
For a great description of why this is so effective, see the recent freakonomics podcast: https://freakonomics.com/podcast/roundabouts/
While I don't know of the safety impact of removing left turns, the actual trip time impact in a busy city is severely understated. In my city (700k people), an old European town, city center has seen the removal of a few key left turns in the past few years. Consequences for traffic outside city center: probably none. Consequences if you want to drive from within the city center to the outside (e.g. go back from a s…
I am biased but why do we even need cars in the city center, or at the very least why should they be convenient? Could there not be a situation where you walk to the edges of the city center to pick up your car and leave from there? There are specific accessibility concerns that certainly need to be accounted for, but the idea that the average driver loses 20 minutes on a trip that should be 5-10 minutes doesn't seem…
Google maps, and other similar routing apps, should offer a no left turn option!
And while we're at it, in the UK at least they should have an option for not sending you down bidirectional single track roads. No, that 35 mile drive down twisty single track country lane with occasional passing spots will not save any time over the 40 mile motorway. Even if the road is _technically_ 60mph, you'll never reach that speed unless you're on a motorbike...
Better yet, replace intersections with roundabouts. But that would mean knocking down a lot of buildings.
That being said I absolutely love roundabouts in low/mid density areas. They finally converted the street I live on from 4 "pack cars into wait groups" stoplights and 1 "the highway just turned into an avenue and this is the first extended stoplight for that" into "never stop heaven" whether you want to just continue through or hop on the highway by putting a bunch of roundabouts and a dogbone underpass in and removing left turns for most of the avenue.
For proper city areas I'm almost certain better results would be achieved by using the space for any form of mass transit instead of more road. That and I shudder to think of roundabout traffic in a bumper to bumper scenario when one of the arteries out of the city gets blocked for 10 minutes (or months of construction).
The first photo also provides an example of a left turn lane blocked by a t-bone crash of two drivers who appear to have not been turning at the time of their crash. That's one way to stop drivers from turning left, but perhaps not the best possible traffic control strategy.
Side note - Based on a quick search of the article's tagline, this article was simultaneously broadcast across many outlets on June 2nd, 2021 [0]. Someone had a motivation to get this distributed far and wide.
[0] https://duckduckgo.com/?q=%22sick+of+dangerous+city+traffic%...
Here in Melbourne Australia, lots is being done to remove right turns (we drive on the left here) at the busiest intersections. Several "P turns" [1,2] have been introduced in the most congested areas, in which you need to go straight through the intersection, then wait to do a U-turn at a designated place, then turn left into the road you wanted to turn right into (or vice versa if you're coming from the other direc…
Earlier quoted context omitted.
And while we're at it, in the UK at least they should have an option for not sending you down bidirectional single track roads. No, that 35 mile drive down twisty single track country lane with occasional passing spots will not save any time over the 40 mile motorway. Even if the road is _technically_ 60mph, you'll never reach that speed unless you're on a motorbike...
There's this awful route Google Maps will give you, through the twisty back roads of SF because it thinks it can get you to the 101 faster. But it's sending everyone that way, so there's huge traffic on these narrow neighborhood roads. It's not a shortcut if everyone knows about it. I think map apps should be optimizing for something more complex, like least amount of directions within a five minute arrival window. S…
One issue is, as you say, that shortest-path routing can overload individual roads. There is an interesting and related concept in theoretical CS: oblivious routing. Instead of solving “What is the shortest route to my target?” locally, you try to determine a selection of routes that, if followed by every participant, minimise congestion (the maximum amount of vehicles over any road, relative to its capacity). Surprisingly, it is always possible to determine such routes, even if they are not allowed to depend on traffic conditions (how many vehicles try to go from A to B, how many from C to D, etc) ― this is what the “oblivious” refers to.
Of course, that does not solve the problem of route complexity.
Here in Melbourne Australia, lots is being done to remove right turns (we drive on the left here) at the busiest intersections. Several "P turns" [1,2] have been introduced in the most congested areas, in which you need to go straight through the intersection, then wait to do a U-turn at a designated place, then turn left into the road you wanted to turn right into (or vice versa if you're coming from the other direc…