The mighty — and automatic — bollard is an important city-building tool that isn’t employed nearly enough in North America. It’s typically used to control car access to small pedestrian-only or pedestrian-first streets. But I guess if you don’t have any of these, then you may not feel the need to install such a device. The above photos are from Bordeaux. And if you want to gain access, you need to hit the intercom button and explain why you’re local traffic. Can you think of any streets in your city that could use a system like this? I can think of many in Toronto.

Years ago Aaron Renn coined an urban paradigm that he labeled “the new donut.” The old donut, of course, is one that many of you will know well: poor downtown (hole in the donut) and wealthy suburbs (ring around the hole in the donut). This is a well documented phenomenon in many American cities.

The new donut reflects today’s return to city centers. It is the filling in – albeit only partially – of the middle of the donut. The reason I say only partially is because the data clearly suggests that, in many cases, there’s now a trough between the immediate core and the outer suburbs. 

In 2015, the University of Virginia published a study called The Changing Shape of American Cities. It looked at things like educational attainment and per capita income in 1990 and then compared it to more recent 2012-2015 data. But most significantly, it plotted this data against “miles from city center.” (I discovered this study via City Observatory.)

Here are educational attainment and per capita income for the 50 largest metro areas in the US. The orange line is 1990 data. The brown line is 2012 data. And the blue line is 2015 data. The x-axis is “miles from city center.”

Compared to 1990, it is clear that there has been noticeable spike in education and income in city centers. For the above composite index, more than 50% of adults over 25 now have a bachelor’s degree. But it has also accentuated the trough that appears to sit, on average, about 5 miles out from the center. 

In some metro areas, such as Charlotte (shown below), there has almost been a complete inversion. Education and income were highest 5 to 10 miles out from the center, but that has since flipped, along with a dramatic spike right in the center.

This is the new donut. If you’d like to see the graphs for all 66 American cities that form part of the study, you can do that here. 

Later this month the new 9.7 km North-South metro line in Amsterdam will start service. Like most large scale infrastructure projects, its opening has been delayed many times. 8 times according to this source. But this post is not about that. It’s about a byproduct of the line’s construction. 

The excavations required for the line meant that two sections of the Amstel River – namely the Damrak and Rokin sites – had to be drained. This took place from 2003 to 2012 and gave archaeologists unprecedented access to the bottom of a river in the middle of a historic city center.

Amsterdam started as a small trading port along the banks of the Amstel River some 800 years ago. So not surprisingly, they found a few things. Over 17,000 objects were found and all of them have been catalogued online according to time period, use, material, and location found.

For the full catalogue of objects, click here. Screenshot of the catalogue shown above. And to learn more about the entire project, start here. There’s a lot of good stuff in there for city nerds.