Gratefully granted that the Petite had a more comfortable and apparently adequately stable ride for a reasonably cautious pilot of the day.
But if equipped with modern braking, (the Petite didn't even come with a front brake, which is where cars typically accomplish 70% of their braking), the single front wheel design would likely prove rollable at speeds below the 27 and a half mph speed which Ralph Nadir successfully prosecuted the Corvair into extinction for a mere 6 years later. This instability would be especially significant if carrying two heavier adults, and having to hit the brakes whilst turning sharply in an emergency avoidance maneuver on a downhill grade, as the effect of both weight centers and weight transfer under braking and turning loads to a front corner of a car not equipped with a wheel to resist this could be over turning. The fact that these cars were both under powered and underbraked ironically allowed them to bypass such scrutiny.
But try going up a hill at 10 mph with no passing lane today, and see how understanding the line of drivers behind you is. Heck, if I am slowed to 45 mph in my Honda Insight whilst travelling the freeways, I'd be run off the road if I didn't promptly scoot into the climbing lane for 18 wheelers, where sometimes even one of these will move into the main lanes to pass me.
Note that Alan's comment was reserved for roads when there was no traffic to speak of.
Modern cars do everything so well that today's drivers, although pleasantly amused by micro cars, would never have the patience or bravado required to pilot one. In the last article, the author praises the car's luggage capacity as it provided enough space for their luggage and chocolates. The Petite comes with but a modest parcel shelf, that if appreciably loaded, would block your rear vision.
They remarked how comfortable they were driving in heavy coats and clothing needed because the Petite didn't even come with a heater despite the air cooled engine being at least a source of easily ducted heat.
And even the motorcycles of their day were were going faster than their 20 mph in the fog. Could their single headlight been brighter than the Petite's duo?