Riding in a Tesla with AutoPilot (2015)

In the Fall of 2015, the electric vehicle maker Tesla remotely upgraded its most recent model year cars (about 50,000 vehicles) with “Auto-Pilot”, making them semi-autonomous (according the NHTSA scale, late Level 2, early Level 3). Elon Musk, the CEO of Tesla, says he expects fully autonomous vehicles within 3 years (i.e. by 2018). I got to take a test ride in one of these vehicles from a friend with a Tesla.

Tesla Model S
Tesla Model S

Upgraded Teslas are able to function in hands-off mode some of the time. They use adaptive cruise control to follow the vehicle in front at a desired speed constrained by a fixed following distance and use lane markings to stay in lane. They change lanes automatically at the request of the driver (who must hit the turn signal).

Tesla Model S User Interface
Tesla Model S User Interface

How it works

As of Fall 2015, none of these functions can be safely performed in a Tesla running “Auto-Pilot” in the absence of driver observation and monitoring. In fact the vehicle requires the driver to periodically return hands to the steering wheel. Rules for automated vehicles are still taking shape. Clearly this is “beta”, and intended for limited access roadways, not city streets, though Tesla drivers do use it on local roads as well as freeways. Here are a few of the issues:

  • Stopping: The vehicles do not yet automatically stop at traffic lights or stop signs, though it is assumed that engineers are working on and testing those functionalities, which may already be in the hands of testers.
  • Following traffic: When following a vehicle in city traffic, the Auto-Pilot may induce the car to run the red if the car in front ran the red (or made a right turn) instead of stopping at the light.
  • Lane marking issues: Ambiguities in lane markings (for instance at freeway merges and diverges, or as a result of road construction or restriping) still create difficulties for the vehicle in Auto-Pilot mode. During the drive, the vehicle would pull toward the exit by following lane markings. Drivers have reported “increasingly less tendency to try to take exits and overall it is clearly improving and needing less driver intervention each week.”
  • Curves: First person observations are that vehicles still over-react on curves (following the average of the inside and outside curve, rather than a fixed distance from the inside curve). Elon Musk has tweeted that slowing for curves is coming, and some Tesla drivers are reporting that their vehicles have been updated. Changes like this are part of the brilliant learning system Tesla has deployed.
  • Merging: The give-way game between merging vehicles and an on-road Tesla cannot yet be safely conducted in the absence of driver intervention. As we drove in the right lane, a Mercedes approached from an on-ramp and neither decelerated to come in behind us, nor accelerated to pass us. Our vehicle stayed at a constant speed. The Mercedes would either sideswipe us or run off the road. The driver manually intervened and accelerated (which Teslas do quite well; I can’t wait for Plaid mode, since Ludicrous mode is injurious enough if you are not braced).

Comparison to Google

The manual intervention thus requires drivers pay attention. Thus far, it doesn’t seem like drivers are being lulled to unawareness with autopilot mode on cars, but lulling is a risk if drivers trust too much. This is the advantage of Google’s all-in approach, where the driver can’t retake control even if they want to. Nevertheless, Auto-Pilot has saved lives already, see the video at this link, where an ill-timed U-turn across traffic which would have otherwise resulted in a crash was prevented).

Teslas do not presently drive independently via a map from origin to destination the way Google’s test cars do. There is no obviously linkage between satellite navigation and mapping and the control function. Teslas appear to be map-independent, and controls are through on-vehicle sensors.

The car still smells new despite being nearly a year old. I believe the car’s filters “Bioweapons Defense Mode” has something to do with that. Tesla also still retains some pluckiness and personality, despite having a market capitalization of $27B.

The vehicles are constantly learning, however, using driver interventions as expert trainers, so many of these problems will resolve themselves. None of these should be taken to mean cars won’t be automated; they will be, as a series of technical hurdles to be overcome, and interesting ambiguities and tacit knowledge on the part of drivers must be made explicit before we can hand our fates to our machines.


See video of the ride.