New Yorkers know it as the busiest traffic time of the year.

Monday marked the start of the annual United Nations General Assembly — a.k.a. gridlock mania.

The annual gathering on Manhattan’s east side triggers the city’s yearly “Gridlock Alert” list, as security upgrades and a return trip by President Donald Trump will surely clog the streets all week long.

Traffic data has shown that average vehicle speeds in the Midtown Central Business District during the General Assembly week drop to under 4 mph, which compares with a slightly more robust 6 to 7 mph on a usual day.

Motorcades are the main reason for traffic headaches, as they crisscross the city while weaving in and out of traffic — including the usual marked green bike lanes.

The bottom line: Avoid midtown if using streets in any way. The MTA urges using mass transit, though bus lanes will be squeezed in midtown, creating delays on those lines.

The following streets are closed until the end of the week:

  • FDR Drive between Whitehall Street and 42nd Street
  • Area Bounded by East 86th Street on the North, East 80th Street on the South, Park Avenue on the East and 5th Avenue on the West; All inclusive
  • Area bounded by 60th Street on the North, 34th Street on the South, 1st Avenue /United Nations Plaza on the East and 3rd Avenue on the West; All inclusive
  • Area bounded by 57th Street on the North, 45th Street on, the South, 3rd Avenue on the East and Madison Avenue on the West All inclusive
  • Area bounded by 58th Street on the North, 49th Street on the South, Madison Avenue on the East and 6thAvenue /Avenue of the Americas on the West: All inclusive
  • Area bounded by West 47th Street on the North, West 44th Street on the South, 7th Avenue on the East and 8th Avenue on the West All inclusive
  • Grand Army Plaza between 58th Street and 60th Street
  • Grand Army Plaza between East Drive and 5th Avenue
  • 8th Avenue between West 49th Street and West 44th Street
  • 7th Avenue between West 56th Street and 59th Street
  • 6th Avenue between West 59th Street and West 46th Street
  • 5th Avenue between East 63rd Street and East 49th Street
  • Madison Avenue between East 58th Street and East 42nd Street
  • Vanderbilt Avenue between East 47th Street and East 42nd Street
  • Park Avenue between East 86th Street and East 45th Street
  • Lexington Avenue between East 57th Street and East 42nd Street
  • 3rd Avenue between 83rd Street and 72nd Street
  • East 83rd Street between 5th Avenue and 3rd Avenue
  • East 63rd Street between 5th Avenue and Madison Avenue
  • East 62nd Street between 5th Avenue and Park Avenue
  • East 61st Street between 5th Avenue and Lexington Avenue
  • West 59th Street between 7th Avenue and 5th Avenue
  • West/East 58th Street between Broadway and 6th Avenue /Avenue of the Americas
  • West/East 57th Street between 7th Avenue and Dead End / FDR Drive
  • West 56th Street between 7th Avenue and 6th Avenue
  • West 55th Street between 7th Avenue and 6th Avenue
  • West 54th Street between 7th Avenue and 6th Avenue
  • West/East 53rd Street between 7th Avenue and FDR Drive
  • West 52nd Street between 7th Avenue and 6th Avenue
  • West 51st Street between 7th Avenue and 6th Avenue
  • West/East 50th Street between 7th Avenue and Dead End / FDR Drive
  • West/East 49th Street between 8th Avenue and FDR Drive Service Road
  • FDR Drive Service Road between East 48th Street and East 49th Street
  • East 48th Street between 1st Avenue and FDR Drive Service Road
  • West 46th Street between 8th Avenue and 6th Avenue /Avenue of the Americas
  • West/East 42nd Street between 7th Avenue and FDR Drive
  • West/East 34th Street between 7th Avenue and FDR Drive