That's what I thought too. Honestly, this hardly changes anything at all from how Market Street currently operates in this section. You hardly ever see any passenger cars using it, other than rush hour. Already today, 90% of the traffic is buses and taxis, and even taxis are rare.

You can’t realistically take a whole city and draw a line down the middle and say “no cars can cross this ever”.

Well, there's Golden Gate Park for a good chunk of the way across SF, which has no surface level streets crossing directly through it...

That’s not true. There are several roads that wind through GGP for driving and parking. Crossover Drive cuts through approximately the middle.

Sure you could. We have more than 2 dimensions.

I guess, but the amount of space and inefficiency that building a highway that literally runs over 1 block over the middle of a city would seem to be not at all worth it.

it wouldn't be a highway, it's called an overpass. and they're quite common.

An overpass tends to make the area underneath it pretty grim: surrounded by concrete with little natural light. I can't think of any examples of a nice shopping street with an overpass above it.

An underpass works well, but is likely to be much more expensive.

My city has a two-way overpass over a popular pedestrian street: https://cdn.olhares.pt/client/files/foto/big/980/9808889.jpg

I think it works well as long as the overpass isn't too wide. Also, using colours and stone instead of raw concrete on the outside helps.

Also there’s two levels of subways running beneath market street so an underpass wouldn’t be feasible

Most cities have that in some form. A river acts as a you cannot cross, except for a few far apart areas. The bay in SF does the same. Then there are sea side cities which have a large shall not cross line.

Rivers have bridges. Seaside cities do not have an undriveable barrier down the middle of it.

Rivers have limited bridges. I live in a city divided by a river (I suspect a large number of those reading this do as well: rivers attract cities for various reasons), most streets just end at the river even though both sides are very developed. If I want to cross the river there is are 5 bridges in the 15 miles of river frontage the city covers (then nothing for many more miles either way). There is great demand to get across the river, we are a tiny city and so the only traffic congestion is getting to the river crossing, but the cost of getting over the river is high enough nobody can justify building another bridge.

I don't know SF, but my guess is that market street will have more crossing than our rivers.

No one in their sane mind want to drive on Market down there these days anyways.

But you have to cross market to allow the city to function, and there's a few major intersections, especially 7th,8th,9th, and 10th. This is pretty much the only way to get access to the south end of SoMA and I-80. You can't "escape" via the Mission, the last option is 13th which exits onto Market street at Duboce triangle.

You can't go under, Bart/muni is there. Only other option is to go over Central FWY style, and the city is more in favor of tearing out freeways.

Lol, there's literally no way for transport to work if they blocked the whole street. Market cuts through the middle of most of SF.

And yes it will make a huge difference. I have through market for several years and most of the problems are caused by drivers on the road.

Chronicle blocked me for using an adblocker so this is from the SF Examiner [1]:

>Better Market Street will be implemented in three phases: Market from Fifth to Eighth streets is phase 1, Market from Fifth to Second streets is phase 2, and Market from Van Ness to Octavia Boulevard will comprise phase 3.

This leaves 9th-11th streets, and streets past Octavia open to traffic. Also, certain types of transport are still allowed. I believe taxis (excluding rideshare apps like Lyft/Uber) were mentioned in another comment, and the streetcars will be allowed as well. I’m sure there’ll be other exceptions.

[1] https://www.sfexaminer.com/news/sf-transit-board-approves-ca...

> If cars are allowed to cross the road perpendicularly, will there be any significant effects from this change?

Yes, every single block between those intersections will have little to no traffic.

If Market street is raised to the sidewalk level and crossing it is allowed at 2mph, I don't think it will be a problem.