I thought these were all removed in the previous century!
The problem with these is that the slots run along the riding direction, and are just wide enough to catch a road bike tire. If your front wheel is unlucky, it will wedge into a slot and stop dead. You will not stop, but according to Newton’s first law, continue moving forward over the handlebars and onto the street.
I noticed this one on the driveway in front of the Wayland Middle School.
If the thing is square, at least it could be put in so the slots run across the road instead of along it.
Update, (March 2009)
I could be in serious trouble now.
Is a story about a man in the UK arrested and held for two days as a terrorist for photographing a sewer grate.