The State of New York just enacted a new law (on June 14, 2019) requiring that 51% of existing tenants agree to buy their apartments before a building can be converted into a condominium or a cooperative. There was previously no requirement for anyone to buy in order for a conversion to take place. Tenants who chose not to buy, could simply remain in the building as a renter.

Supposedly, the real estate industry believes this new requirement will be a largely impossible threshold to meet, meaning that condo/co-op conversions could now be dead in NYC. There's also an argument that conversions have historically helped many middle class New Yorkers buy a home since they sometimes (usually?) had the chance to buy their apartment below market at the time of a conversion.

I'm not familiar enough with this space to be able to opine on the merits of these arguments, so I won't. Perhaps some of you will in the comment section below. Instead, I will leave you all with a chart showing the median condo sale price in Manhattan over the last ~30 years (taken from the same WSJ article). I like seeing long(er) term charts. Maybe you do too.

We are in West Virginia now, where the only kind of housing that we have come across is -- not surprisingly -- low-density, detached, and single-family. Indeed, approximately 75% of the residential land across the entire US is estimated to be zoned for detached single-family homes. Using data from UrbanFootprint, the NY Times recently published a series of city maps outlining the percentage of land dedicated exclusively to this housing type.

In some cases, such as on residential corner lots in Portland, duplexes are allowed. But generally speaking, the pink corresponds to detached single-family housing. About 15% of residential land in New York City is zoned for this, compared to about 94% of the land in San Jose. Interestingly enough, none of the residential land in Manhattan is zoned to accommodate detached single-family housing.

The latest project out of MIT's Senseable City Lab examines the "sensing power of taxis" in various cities around the world. Looking at traffic data, they determined how many circulating taxis you would need to equip with sensors if you wanted to capture comprehensive street data across a particular city. This might be useful if you wanted to measure things like air quality, weather, traffic patterns, road quality, and so on.

What they found is that the sensing power of taxis starts out unexpectedly high. It would only take 10 taxis to cover 1/3 of Manhattan's streets in a single day. However, because taxis tend to have convergent routes, they also discovered rapid diminishing returns. It would take 30 taxis (or 0.3% of all taxi trips) to cover half of Manhattan in a day, and over 1,000 taxis to cover 85% of it. A similar phenomenon was observed in the other cities that they studied: Singapore, Chicago, San Francisco, Vienna, and Shanghai.

However, if you look at the percentage of trips needed to scan half of the streets in a city, Manhattan has the lowest rate at 0.3%. Vienna is the highest at 9%. But I'm not sure if this is a function of the utilization rate of their taxis or if it has something to do with urban form. Singapore has a similarly low rate (0.44%), but its street grid looks nothing like that of New York's.

Here's a short video explaining the project: