[circuit10]

As someone who doesn’t drive but has done a UK theory test - aren’t you supposed to stick to the “slow lane” (no matter how fast you’re going) unless you’re overtaking? And that’s why it’s not actually called the “fast lane” but the “passing lane”. So I don’t see why you would be in the passing lane unless you’re going faster than others anyway. And there are plenty of lorries and coaches (trucks and buses in US terms?) that are physically limited to below the speed limit anyway

Though I’ve heard people treat it differently in the US

[toast0]

The slow lane and passing lane dichotomy makes sense in a rural highway with two lanes in your direction.

It makes less sense in an urban environment with 5 or more lanes in your direction. Vehicles will be traveling at varying speeds in all lanes, ideally with a monotonic gradient, but it just doesn't happen, and it's unlikely to.

In California, large trucks generally have a lower speed limit (however many trucks are not speed governed and do exceed the truck limit and sometimes the car limit) and lane restrictions on large highways. Waymo may do well if it tends toward staying in the lanes where trucks are allowed as those tend to flow closer to posted car speed limits. But sometimes there's left exits, and sometimes traffic flow is really poor on many right lanes because of upcoming exits. And during commute time, I think the HOV lane would be preferred; taxis are generally eligible for the HOV lane even when only the driver is present, but I don't know about self-driving with a single or no occupant.

[circuit10]

Isn’t the situation you’re describing where speeds vary due to queues going to be in heavy traffic where cars aren’t getting close to the speed limit anyway?

(also it’s kind of amazing that 5 parallel lanes is considered normal in the US… I think the most I’ve ever personally seen in the UK is 4 and that’s only on very major routes, and we don’t have any exits on the wrong side of the motorway)

[toast0]

> Isn’t the situation you’re describing where speeds vary due to queues going to be in heavy traffic where cars aren’t getting close to the speed limit anyway?

Not necessarily. I've seen things like the left two lanes at free flow (speed limit or above) and the right two lanes at full congestion (~ 10 mph), and the middle lane(s) somewhere in between. But then you also have sometimes where the left lane is only doing 60 for some reason, but the next two lanes are at or above the speed limits. It's a complex system.

Wrong side exits for interchanges between highways are common, depending on site details and relative flows. When there's congestion on a left exit, you then get situations where the right lanes are flowing faster than the left lanes (sometimes much faster). I don't think interchanges as left exits are necessarily awful.

Wrong side exits to surface streets have been discouraged for new construction for quite some time, but there's a fair number of "legacy exits" in some areas. They're not so bad when there's only two lanes in your direction; but when there's been highway expansion, it can get pretty hard to use. And inevitably rebuilding to current standards would causes a lot of confusion and delay, it's postponed. My exemplar of the worst left exits, the Milwaukee Zoo Interchange, was rebuilt in 2012-2022 and I can't find pictures of what it was before, but you had a sizable interchange with right and left exits to other highways, combined with several surface street exits and entrances on both sides, and I think two through lanes. It was a mess.

[TulliusCicero]

5 each way is decently big imo but it really depends on the area. A freeway near a really large metro that's particular car-dependent can easily go higher.

[jjfoooo4]

Yes. People do in fact safely drive the speed limit.

If "we'll have too many cars on the freeway following the speed limit" ranks as a serious concern, I think we've really lost the plot.

I recently drove by a fatal accident that had just happened on the freeway. A man on the street had been ripped in half, and his body was lying on the road. I can't imagine the scene is all that unlike the 40 thousand other US road deaths that happen every year.

As a driver I'm willing to accept some minor inconvenience to improve the situation. As a rider I trust Waymo's more than human drivers.

[iteria]

It depends on where you are. There was a protest in in Atlanta about the speed limit. What did they do? They got in every. Single. Lane. As did the speed limit. This backed up traffic for miles. It stopped commercial delivery and had ramifications for entire area. The protesters were arrested. For going the legal limit. The speed limit did not change, but there is a reason why it's never enforced.

I've lived in a couple of places where going the speed limit is a whole problem that can cascade outside of just yourself. There is an argument to be made that perhaps then the speed limit shouldn't be that low, but in driving safety is far more important than legality. It will be interesting to see how Waymo handles these realities when it gets to those areas.

[Yizahi]

First of all, while I hear about that protest first time, I'm 99% sure that they were not fines for driving under speed limit, but because of the unreasonable obstruction of the left lanes. This is prohibited probably in all countries, regardless of the limits in use.

Second, it is a widely known issue, that a slower mowing car is causing ripple-like delays far from the car itself. For example when a police car is driving inside the traffic flow. But if most of the cars are following the rules, like 95% of them, then one law abiding Waymo would fit just fine. In EU, with the deluge of speed traps and mobile patrols, most of the cars are driving under the limit, and honestly it feels fine. I'm originally from a country where +20 above was like a norm, and fast cars were +40 or more, so adjusting to EU took some effort. But now I don't even feel the need to speed, especially if it is 140km/h highway (86 m/h)

[robocat]

I'd really love to see some good statistics on the risks of speeding on motorways.

I often wonder about laws that are ostensibly there to prevent dangerous actions, about whether they actually help prevent dangerous driving.

This guy analyses tailgating: https://m.youtube.com/watch?v=6n_lR09sjoU Awesome software although he seems biased (e.g. no mention of pedestrians), but he does say that tailgating is much more dangerous than speeding.

I'm interested whether cameras will start to catch dangerous drivers. I regularly seeing drivers do very dangerous things. Yet we have no easy way to train them (for those that care but are unaware), or catch them (for the antisocial that don't care).

[jjfoooo4]

I mean, isn't the most common reason people tailgate is that they're frustrated that a slow driver is in a lane they want to use to drive fast in?

[bluGill]

Not a slow driver in most cases, many slow drivers - all who want to go faster but cannot. There is just so much traffic that you can't go faster, and neither can the person in front of you.

I used to drive 20 under all the time (I achieved 57mpg once doing that) - but since this was an empty rural highway the few cars that were around saw me well in advance and moved over and passed without a problem.

[robocat]

I am surprised that research backs you up... my guess had been that the majority of tailgaters are just arseholes (technical term) so I checked:

  There is substantial research that frustration with a slow driver in a fast lane is a significant factor in aggressive tailgating (as a way to express anger, control, or impatience) to get others to change lanes.

There's a balance between selfish lane-hoggers and selfishly impolite/dangerous tailgaters.

But perhaps research doesn't measure arseholeness?!

For selfish reasons I usually let dangerous tailgaters pass me: I want to avoid the bad outcomes from pissed off aggressive drivers.

If I'm stuck behind someone slow, I usually politely wait or politely flash lights or politely tap horn. I think Tailgating is personally dangerous as a way to signal my displeasure and I value my life highly. Polite drivers generally let one pass, and impolite drivers do whatever the fuck they want.

Regardless, it would be interesting to see stats on how risky tailgating actually is (unfortunately stats are sure to be biased by correlation versus causation).

[maxerickson]

If there are vehicles going slow due to capability, you are pretty likely to be in an area where traffic density means that there's lots of vehicles in all the available lanes.

Plenty of people do not follow the rules about staying to the right.

[bigstrat2003]

Yes, you are correct. But lots of people in the US have no idea how to drive.

[tfehring]

You’re correct. There are people in the US who drive in the passing lane without passing, but most consider that a bad practice, as it makes roads both less efficient and less safe.

[whimsicalism]

i think this is a state by state cultural difference

[__s]

In Ontario we have lots of 3 lane highways (we'll ignore Toronto area, where speed is limited by traffic anyways). What happens is that trucks & people getting on/off exits are in right most lane. Middle lane is everyone else, going 10-20 km/h over speed limit. Leftmost lane is people passing, or the maniacs going over 150 km/h while relying on their map system to alert them of highway patrol

[TulliusCicero]

You're framing the problem space in a way that doesn't match major freeways in the US at all. There's a bunch of lanes, and you need drivers spread out across all of them, otherwise traffic would slow to a standstill.