Details concerning New York City’s first-ever speed camera program are scarce. To slow down as many speeding drivers as possible with the small number of cameras permitted by Albany, this is as it should be.

On Tuesday, DOT Commissioner Janette Sadik-Khan joined Mayor Bloomberg at P.S. 81 in Riverdale, where 96 percent of motorists observed for a DOT school area survey were speeding. While a camera or cameras will presumably be deployed to slow drivers around P.S. 81, it’s one of 100 schools around which 75 percent or more of drivers speed [PDF]. To cover even a fraction of NYC school zones with a relative handful of cameras, flexibility is key.

Here’s Sadik-Khan, as quoted by WNYC and the Daily News: “The cameras are mobile so we’ll be able to move them around and address high-speed locations that may change over time. Any school where there’s excessive speeding will be fair game. One of the deterrents is that people don’t necessarily know where they are.”

The bill passed by the State Legislature limits NYC to the use of 20 cameras at a time. Cameras will be operable only from one hour before the school day begins to one hour after it ends, and from 30 minutes before to 30 minutes after school activities. A driver can go up to 10 mph over the speed limit without getting a ticket, and camera-enforced penalties will be capped at $50 — billed to the vehicle owner — regardless of how fast an offending motorist drives. No license points or insurance penalties will be attached. The legislature placed a five-year sunset clause on the program.

DOT told us that, since the system will be handled by a vendor, operational details have yet to be worked out. But a look at other mobile speed camera programs sheds some light on how they might work in NYC. Mobile speed cameras are often mounted in SUVs or other vehicles, and localities might or might not disclose where they are, or where they might be. Washington, DC, uses a combination of mobile and fixed cameras. The MPD posts a list of six dozen “enforcement zones,” most identified by block number, where cameras may be at any given time.

The Albany speed camera bill says NYC “may” install signage to notify motorists that cameras are in use, and warning motorists that they are about to enter a monitored school zone. So it could be that motorists know only that cameras will be used near schools.

Juan Martinez, general counsel for Transportation Alternatives, says warning signage would lessen the program’s effectiveness. “Because that tells drivers it’s ‘okay’ to speed a block later,” he says.

Then there is the question of decoys, which were recently deployed by police in Laurel, Maryland. Again, DOT said their use would depend on the vendor.

“It does all come down to the vendor,” says Martinez, “how the cameras will be mounted, how many cameras will be used, decoys, et cetera.”

A DOT spokesperson told us the 100 high-priority schools will be “candidates” for automated enforcement, echoing Sadik-Khan’s remarks about any school where there’s a lot of speeding being “fair game.” Martinez believes the less motorists know about where cameras are, the safer school zones will be.

“I imagine DOT will be cagey about which schools get the treatment — and I hope they are, because again the technology works best when drivers don’t know where the cameras are, so they expect them to be everywhere.”