There’s nuclear security, and then there’s street security. NUCLEAR-SUMMIT/OBAMA

High-level delegations from nearly 50 countries gathered in Washington to talk, talk, talk, and talk some more about keeping the world safe from nuclear terrorism at the Nuclear Security Summit hosted by President Barack Obama.

That in turn required Washington to cope with ensuring the safety of the world leaders gathered to mull world security.

Ripple effect: Plenty of local scare talk about street closings, traffic tie-ups and nightmare commutes that kept many people off downtown streets on Monday, the first day of the two-day summit.

Side effect: an easier commute, lighter traffic, no typical morning gridlock. (Hey maybe there’s an answer to Washington’s nightmare rush hour traffic jams).

A massive security cordon surrounded the summit site with camouflage-wearing National Guard troops and a heavy U.S. security presence.