I disagree. I had an 86 Toyota Tercel 4WD wagon. It weighed more than the Insight, had the 4wd drivetrain to lug around and was not as aerodynamic, and it only had 62 hp. It did OK on the expressway except when stuck behind a big powerful vehicle that would go down the on ramp at 25-30 mph. They could accelerate in the last 100 yards to get up to speed, the Tercel had a problem then, but that was the only time.
BTW, the Geo Metro also had a 3 cylinder, 1 liter, 62 hp engine.