The explosions in London today - coming just two weeks after suicide bomber attacks in the London Underground - remind us again of just how difficult it is to protect any city's transportation system. Earlier this week, the New York Daily News had an update on the MTA's "first wave of major anti-terrorism projects," including the installation of high-tech surveillance systems to protect the underwater tunnels leading into Manhattan:

"The systems will be able to detect intruders entering the 14 subway and commuter rail tunnels leading into Manhattan - sending alarms and images to Metropolitan Transportation Authority police and anti-terror staff in command centers, sources said. Cops would be dispatched immediately to thwart any possible attack."

It's a solid step forward, but the article hints that the MTA has been dragging its feet on the whole process. Despite having access to more than $500 million in funding for anti-terrorism, the MTA has spent only a miniscule fraction of this money -- money that can be used to protect New Yorkers.