Remove left turns for less dangerous city traffic • Hacker News Board

Re: Remove left turns for less dangerous city traffic

#171

Post by aliasEli » Wed, Jun 09, 2021, 2:25 PM UTC

kibwen wrote: post #116

burlesona wrote: post #51

One of the best ways to eliminate left turns is to replace four way intersections with roundabouts. This has the advantage of working even where there isn’t a grid to facilitate the “3 right turns” strategy. For a great description of why this is so effective, see the recent freakonomics podcast: https://freakonomics.com/podcast/roundabouts/

As a pedestrian and a cyclist, please, no. I don't trust crossing a lane of traffic unless traffic is fully stopped, and nobody expects to stop in a roundabout, so I don't even feel safe using the crosswalks and hoping that the traffic will yield. Let cars come to a complete stop.

It depends a lot on the country you are in. In the Netherlands pedestrians and cyclists normally get priority, because the car is making a right turn while the other groups are continuing in a straight fashion. What probably also helps is that when a car is involved in an accident with a pedestrian/cyclist the default assumption is that the car driver is guilty.

Re: Remove left turns for less dangerous city traffic

#172

Post by aliasEli » Wed, Jun 09, 2021, 2:38 PM UTC

jakubp wrote: post #129

mschuetz wrote: post #40

Earlier quoted context omitted.

> As someone who doesn’t live in the city center, and has no easy means of mass transportation to get there, my response is: fine I just won’t go then. You lose my money. The bussiest city centers tend to be the least car and most pedestrian friendly ones. Park the car at the border of the center, then walk into the center.

When you say "then walk into the center", you do realize you are talking about a (edit) 20-30 minute walk one-way. A car could cut that in 2 minutes. In my lifetime I was a driver in a city where it took exactly 5 minutes door-to-door from my home to ANY location in the city (at night). During the day it was maybe 8 minutes. Then some years went by. I now live in a city where at night it's 20 minutes, and during the…

Don't you ever use public transportation? Most larger European cities have quite acceptable transportation. Also one of the reasons it takes longer is probably that there far more cars on the road and everybody is using their car even for short trips.

Re: Remove left turns for less dangerous city traffic

#173

Post by Fire-Dragon-DoL » Thu, Jun 10, 2021, 1:30 AM UTC

rjsw wrote: post #104

Zababa wrote: post #88

Earlier quoted context omitted.

As a French, it's really surprising to see how other people from other countries aren't used to roundabouts. I really like how diverse roundabouts are here. Some are arranged like gardens, some have flowers, some have sculptures, some have decorations made by the local school. A funny anecdote: we used to go to Pontarlier from time to time because our grandparents had a house here. Every time we went, we saw that [1]…

The French are not very good at using roundabouts IME, they don't indicate which exit they intend to use.

I drive in Italy and Canada, the signaling is very different. In Italy you would signal left to indicato "entering", then signal right when about to leave.

In Canada you signal before entering, and signal right when you plan to exit right, left when left, nothing when going straight.

This assumption doesn't work for Italy wherte there are roundabouts with 5 or more roads involved.

Re: Remove left turns for less dangerous city traffic

#174

Post by raffraffraff » Sun, Jun 13, 2021, 3:45 PM UTC

Kim_Bruning wrote: post #148

whatevertrevor wrote: post #144

Earlier quoted context omitted.

What if they moved the bike/pedestrian crossings to further along the lanes away from the roundabout? This would give more room for the cars to exit the roundabout without encountering immediate cross traffic, and more "collection space" on the exit itself so if a driver does have to stop to let a pedestrian/cyclist through they don't impede the roundabout traffic.

Posted video link of this type of roundabout in action just above ( https://news.ycombinator.com/item?id=27415631 ) There's just sufficient space for 1 car to tuck in each time. Note that the priority here is not necessarily to maximize car throughput at all costs; but to ensure safety for all modes of traffic; and to do so inside a given amount of space and cost. Given a different set of parameters, a different inte…

It seems to work during that 5 minute segment, but at 1.45 it looks like this system could get gridlocked. If vehicles are blocked from exiting a roundabout for long enough, there's a risk that the whole thing will fill up. When this happens, it can only get unblocked quickly if the vehicles blocking the exits wish to leave via those exits. Edit: nope, the system can continue to move, but when more exits are blocked, the system throughput drops sharply to zero. I'd love to see this roundabout during rush hour.

For cyclists safety, this system works because the cycle lane is so far outside the vehicle lane, and it is right before pedestrian crossing. Most of the roundabouts with bicycle lanes that I have encountered, they just used a different coloured tarmac at the edge to show cyclists where they should risk their lives. They're not at 90 degrees to the cars, they're literally side-by-side. In that situation, cyclists are in greater danger of getting side-swiped by a car exiting the roundabout.