The primary purpose of the city is transportation. Sure, we share infrastructure like sewers and power lines, but the real reason we live in dense cities is so we can have a short travel time to the things in our lives, be they jobs, friends, shopping or anything else.

Sometimes that trip is a walking one, and indeed only the dense city allows walking trips to be short and also interesting. The rest of the trips involve some technology, from the bicycle to the car to the train. All that is about to change.

A huge opportunity awaits a young social media company that is poised to take advantage of the fall of Facebook (and Twitter). Is somebody out there ready to carry the ball and make it happen. It probably has to be somebody already with most of this done, or even operating.

The NHTSA/SAE "levels" of robocars are not just incorrect. I now believe they are contributing to an attitude towards their "level 2" autopilots that plays a small, but real role in the recent Tesla fatalities.

You've probably heard the catchword in the bitcoin/crytpocurrency world of "HODL!" Based on somebody's typo, it is an encouragement to hold on to your bitcoins rather than sell them as the price ramps up to crazy levels. If you're a true believer, you will HODL. Don't cave in to the temptation and pressure to sell (SLEL?) but be sure to HODL. (Previously I wrote about the issues which occur should Bitcoin's price actually stabilize.

You, by definition, read blog posts. But the era of lots of individual personal web sites seems to be on the wane. It used to be everybody had a "home page" and many had one that updated frequently (a blog) but I, and many other bloggers, have noticed a change of late. It can be seen in the "referer" summaries you get from your web server that show who is making popular links to your site.

I have many things to discuss on the problem of "fake news" (which is to say, deliberately constructed false reports aimed to be spread to deceive) and the way it spreads through social media. This hot topic, seen as one of the largest threats to democracy to ever arise -- especially when combined with automated microtargeting of political propaganda -- is causing people to clamour for solutions.

Boring administrative announcement: In a move long overdue for me, access to this blog and my other large sites will now be exclusively through "https" (ie. encrypted web.)

I set up this, of course, using the great tool Let's Encrypt which was created with support from the EFF. This project and the tools around it take a big step towards making the internet encrypted by default. Let me know if you experience any problems. But then I guess you aren't reading this if you are. Oh well!

The Uber car and Tesla's autopilot, both in the news for fatalities are really two very different things. This table outlines the difference. Also, see below for some new details on why the Tesla crashed and more.

Last week, buried in the news of the Uber fatality, a Tesla model X had a fatality, plowing into the ramp divider on the flyover carpool exit from Highway 101 to Highway 85 in the heart of Silicon Valley. Literally just a few hundred feet from Microsoft and Google buildings, close to many other SV companies, and just a few miles from Tesla HQ. I take this ramp frequently, as does almost everybody else in the valley. The driver was an Apple programmer, on his way to work.

How does a robocar see and avoid hitting a pedestrian? There are a lot of different ways. Some are very common, some are used only by certain teams. To understand what the Uber car was supposed to do, it can help to look at them. I write this without specific knowledge of what techniques Uber uses.

In particular, I want to examine what could go wrong at any of these points, and what is not likely to go wrong.

The usual pipeline looks something like this:

Lost in all my coverage of the Uber event is a much more positive story from San Francisco, where Police issued a ticket to the safety driver of a Cruise test vehicle for getting too close to a pedestrian.

Uber has reached an undisclosed settlement in the fatal incident with the victim's husband and daughter. This matches my prediction of Uber's likely best course of action, since it will shut down much of the public discussion and avoid dragging all sorts of details out into the open in a lengthy trial. The settlement comes with an agreement for silence, as you might expect.

Yesterday we saw the state of Arizona kick Uber's robocar program out of the state. Arizona worked hard to provide very light regulation and attracted many teams to the state, but now it has understandable fear of political bite-back. Here I discuss what the government might do about this and what standards the courts, public or government might demand.

The governor of Arizona has told Uber to "get an Uber" and stop testing in the state. With no instructions on how to come back.

Unlike the early positive statements from Tempe police, this letter is harsh and to the point. It's even more bad news for Uber, and the bad news is not over. Uber has not released any log data that makes them look better, the longer they take to do that, the more it seems that the data don't tell a good story for them.

In the wake of the Uber fatality, I'm seeing lots of questions. Let's consider the issues of crosswalks and interventions by safety drivers.

The importance of the crosswalk

Crosswalks actually are important to robocars in spite of the fact that they still should stop for a pedestrian outside of a crosswalk.

Today I'm going to examine how you attain safety in a robocar, and outline a contradiction in the things that went wrong for Uber and their victim. Each thing that went wrong is both important and worthy of discussion, but at the same time unimportant. For almost every thing that went wrong Is something that we want to prevent going wrong, but it's also something that we must expect will go wrong sometimes, and to plan for it.

Major Update: Release of the NTSB full report includes several damning new findings

Update: Analysis of why most of what went wrong is both terrible but also expected.

Update: More information in following posts, particularly impressions of serious possible errors by Uber.

Update: Did the woman cross 3.5 lanes of road before being hit?

It's just been reported that one of Uber's test self-driving cars struck a woman in Tempe, Arizona during the night. She died in the hospital. There are not a lot of facts at present, so any of these things might be contradicted later.

I've been doing some analysis of the "HODL" movement (which attempts to use social pressure to convince people to hold on to Bitcoin and other holdings, rather than taking the normal profit-taking steps after such a large appreciation.) I believe that HODL goes against what a cryptocurrency is supposed to be about, since to be valuable it has to be useful, and to be useful, people need to be using it, not holding it. I will explore this in another article next week.