[simias]

I suppose, but you obviously decrease the average speed that way. It could be pretty significant too, if you want to reach bullet-train speed for your maneuvers you have to slow down to around ~300km/h from your 1000+km/h cruising speed.

That's a delta-v of at least 700km/h or about 200m/s. At a deceleration of 1g it'll take about 20 seconds, and an other 20 seconds to get back to speed after that. And 1g sounds like a lot for public transportation, especially for so long. Maybe they could rotate the seats to keep the acceleration downwards from the point of view of the passengers?

And obviously it'll take a lot of energy to re-accelerate the car, so you might want to store the braking energy to reuse it but I'm not sure if it's practical to store such a huge amount of energy so quickly.