The transportation revolution just hit its first speed bump. In a blow to next month's launch of the revolutionary Segway Human Transporter, San Francisco, Calif., became the first large municipality to ban using the vehicle on sidewalks.

No big deal? Think again. Because the high-tech scooters max out at just over 12 miles per hour, getting around on busy urban roadways would pose a dangerous challenge for drivers. The lure of negotiating tight pathways efficiently was a big selling point, and the $4,950 scooter was a brisk seller in recent weeks on Amazon(Nasdaq: AMZN).

While most states have approved Segway-enabling legislation, California allows cities to opt out. Maybe this is just a San Francisco thing, but the city's signature rolling streets seem like a perilous fit for the Segway.

It's ironic that the West Coast would strike the first shot, as the area's tech visionaries such as Apple(Nasdaq: AAPL) CEO Steve Jobs and Amazon's Jeff Bezos were singing the Segway's praises even before it was unveiled two years ago. The hype machine was running on 11 at the time, and postal delivery trials were ultimately launched.

Segway had all the momentum in the world, but for now, at least, one city is stepping on the brakes.