That's questionable. Flow should improve from increased spacing; it might even offset the density decrease.

Even if the length of the cars end-to-end is often greater than the length of craggy narrow street between tightly packed but unevenly placed intersections with anywhere from 3 to 8 entry points? Even when all of the 5 highways people are trying to enter and exit– all within the same mile– are all completely backed up? I'd have to see that to believe it.

Those seems like situations where extra spacing will help accomodated unexpeded mergings and lane changes without slowing traffic down.

The majority of the roads that aren't highways do not have lanes. The road layout is largely from a hundred or two years before cars existed.

I fail to see the relevance of this comment?

>>> Those seems like situations where extra spacing will help accomodated unexpeded mergings and lane changes without slowing traffic down.

>> The majority of the roads that aren't highways do not have lanes.

> I fail to see the relevance of this comment?

... you don't see how roads lacking lanes applies to the efficiency of merges and lane changes?

So the point you were trying to make is that single land roads don't face traffic issues from merges and lane changes? That seems to trivially be false in my experience. Having driving all over the USA on roads with a single lane in each direction, merges and lane changes are by far the biggest cause of traffic slow downs.

Sure thing, bud.

Do you suppose average speeds would be higher or lower without the frequent accidents due to failure to brake in time?

The traffic is not frequently caused by accidents. It's a small city so it's pretty clear when that happens. We have some of the lowest accident stats in the country. It's probably because any time there are a significant number of cars on the road, the entire region slows to a crawl.

I'm pretty much out of the habit of using cruise control even with newer adaptive cruise control because it really encourages maintaining a constant speed even on roads that are really too busy to allow it.

In this city, even at 3:30 in the morning on Sunday, cruise control is just useless. It's a spaghetti pile of twisty roads and a billion intersections. Even on the major thoroughfares, you're not going to drive more than 20 seconds without hitting a intersection. To make matters worse, it's all way too disorganized to efficiently coordinate-- almost nothing is perpendicular-- so when traffic is light they just have very short light cycles and you're nearly guaranteed to hit a red light in a few blocks, max. Most residential streets are only wide enough to accommodate one car, but in many cases there's no logistical way to make them one way, so you just have to get good at constantly negotiating who should yield and who should go with oncoming traffic. That, specifically, causes shockingly few problems! But it makes for complex traffic patterns that require a lot of cognitive load to handle. If there was good public transit here, it would be great.

The situation is similar in the Chicago area. Some roads are almost perpetually bogged down. If there is an accident or stalled car, it gets worse. I see two things that affect flow.

1. As traffic builds and distance between cars decreases, the flow becomes susceptible to "shock waves". (Just search Youtube for "traffic shockwave" for an example. I think it happens when someone taps their brakes and the next car behind them has to brake a little harder ans so on down the line until traffic comes to a complete stop.

2. As a commuter and occasional weekend driver I recognized two traffic patterns. During normal commutes, the same drivers drive the same routes every day and most settle into a pattern of maintaining speed, remaining in lane, moving to merge and so on in harmony with other drivers. There is the occasional outlier, driving slower than everyone else or weaving in and out and trying to get ahead by weaving and passing in whatever lane momentarily has space. On weekends I see drivers who are unaccustomed to the driving situation and simply don't mesh well with other traffic. Even though there is generally less traffic, it does not flow as well. There is more lane changing and stuff like crossing three lanes to get to an exit because they forgot where they needed to exit.

Excess traffic is a problem and unfortunately we seem to be able to overfill the available capacity any time it is increased.

When I worked in downtown Chicago I was very happy to be able to take commuter rail to work rather than to have to drive, but those options seem to be more the exception than a regular option. That's a different discussion.

Yeah I've had my fair share of big city traffic, but this is very different. In many ways driving here is a lot easier than driving in a place like downtown Chicago or Manhattan because it's much much much lower-volume, so there's a lot less action you have to pay attention to, but all of the roads are tiny and twisty. It's like heart circulation vs pinkie tip circulation. And since it's so small, even being slowed down to a crawl from one end of the city to the other as part of a longer drive would affect your drive less than even moderately bad traffic in a metropolis.