CR compared our former and current car

The BMW i3-REx was my 'gateway' to EV travel and taught me many valuable lessons. Around town, it is a perfectly fine EV and the gas engine provides enough that I have no problem with doing +700 mi cross country trips. But at 2014, there was little trade-in value compared to the $18.3k trade-in for the 2017 Prius Prime Plus that still had some of the 3 year, manufacturer warranty left.

Although I could and did use the Prius Prime when the BMW had to go to the service department "Spa," the 25 mi EV range meant it was a 3-stop car. The 3d stop means the next is a charger or burn some gas. It also had less interior space than the Model 3 and AutoPilot is awesome compared to TSS-P. The BMW has dynamic cruise control and reads speed limit signs but it has been doing that since 2014. It has not gotten any better.

Bob Wilson

 

The "auto steer" which keeps the car in the lane is remarkable and gotten better. The first version would get a little too close to the center line in a right hand curve for my comfort but either I've grown used to it or it is doing a much better job of steering in a curve. Even with just the Tesla Lane Keep Assist, the car will steer back from crossing a lane marker and try to stay in the lane with a gentle 'ping-pong.' In contrast, TSS-P beeps and puts in steering input that will cross the lane to the other side. In contrast to these two, auto steer keeps the car centered even on dirt roads.

The dynamic cruise control (Traffic Aware Cruise Control) is as good as the Toyota TSS-P and better than the "magic eye" of the BMW. The BMW can get confused driving into the sun; into a shadow over the road when headed towards the sun, and; occasionally false alert when there is a road sign over an overpass. Both TSS-P and AutoPilot share similar problems dealing with crossing traffic and testing has show that tractor trailers without aero-skirts can be missed by AutoPilot. I don't have the Prius Prime to see if shares this same blindness and haven't tested the BMW, yet.

Autopilot does have some weaknesses which are easily recognized and handled. Exiting a divided highway often requires manual steering, not always, but frequently. Also, if one lane become two, the car isn't sure which lane to take so it acts like a "nervous student driver." If there is a leading car, it follow that car into its lane. Some angled intersections have lane lines that can fool auto steer to try and drive into the opposite lane. Also, there are crossing intersections in Mississippi where the absence of right-hand dashed lines but solid right edge lines can fool auto steer to 'split the difference' and try to drive into the opposite side ditch:



All of these are easily recognized once you've experienced them but there is no trainer. It can be scary to first time users. Surveys have shown about 80% of the Tesla owners trust AutoPilot while being alert and ~20% do not. Here is a short video from my dash cam showing some of the AutoPilot challenges:

Regardless, AutoPilot has impressed me with:

• Following the lanes in sheets of driving rain when even I was starting to have difficulty seeing the lane markers.
• Handling "micro-sleep" events - Long story short, my wife's week in the hospital; my camping out in her room, and; forgetting my CPAP machine, led to five "micro-sleep" events returning home on a barren, two lane road. AutoPilot kept us from wandering into on coming traffic or driving into the ditch. IMHO, AutoPilot saved us from five accidents so I'm sold on the technology. TSS-P would have just beeped and steered us across the lane into the other side. BMW has no lane keeping technology.

I've also tested "Navigate on AutoPilot" and it has a lot of promise. It will ask to change lanes to deal with slow traffic or approaching exit ramps. It does require driver confirmation of such changes. However, it is geo-limited to divided highways so it is not a universal solution, yet. AutoPilot works anytime I ask as long as it can see the lane markers and/or a curb.

Bob Wilson