I rode in my first self-driving car yesterday.

I was in Scottsdale with my friend Bhargav Shivarthy who downloaded an app and ordered one of the taxis operated by Waymo, a unit of Google.

The car arrived and he clicked a button on his phone to unlock the doors. An automated voice welcomes you and promises not to record your conversation which seems unconvincing.

It’s a weird experience. On one level you know what to expect based on news reports.

You know there will be no driver. You know it will be exciting but feel a bit anxious. You aren’t surprised when bystanders gawk.

And there are things I didn’t anticipate, such as how smooth the ride was and how safe I would feel.

By far the biggest surprise was that the cars don’t speed.

That may sound obvious, but until you ride in a car that religiously keeps to the speed limit you don’t realize how much everyone else in America breaks the law.

Speeding is the default, not the exception in the country.

When you drive the actual speed limit, life slows down.

The expectation that driverless cars would be rolled out quickly has been stymied by high-profile accidents. It’s left consumers unclear whether or when such cars will be available.

Driving even a short distance is enough to make me believe that it’s probably inevitable.

Assuming driverless cars do arrive, I see two big implications from slower speeds.

The first is that vehicular deaths could plunge. Currently, about 43,000 people a year are killed in car accidents, almost one third of which involve speeding.

In addition, slower cars and trucks could translate into a decline in economic growth.

Of course, towns and cities could react by raising the legal speed limits.

Bhargav and I speculated about safety and speed and other features of the Waymo as it ferried us around town.

We didn’t want to talk too loudly, however, because we were pretty sure the car was listening.