asphalt wearing course -- a layer of asphalt, generally three inches thick, that sits on top of the concrete base, providing a smooth surface on which vehicles ride

backfill -- the dirt and sand used to fill in a street around underground utilities and below the concrete base

Barnes Dance -- the timing of traffic signals at an intersection to give pedestrians “Walk” signals in every direction; an example is currently in place at the intersection of Broadway, Park Row, Vesey, and Ann Streets

bathtub -- the sub-grade basement of the main World Trade Center site (divided into east and west sides), whose slurry walls withhold groundwater from the site

bollard -- a short post set in the sidewalk or roadway to block vehicles from entering an area; typically used for security purposes

building line -- the edge of a building, excluding the sidewalk (see usage under “capital street reconstruction”)

caisson -- a watertight chamber used to install the foundation of a structure

capital street reconstruction -- the reconstruction of all components of a street from building line to building line, including the asphalt wearing course, concrete base, curbs and sidewalks; generally involves repair, replacement, and relocation of utilities

catch basin -- an underground receptacle with a surface grating for street drainage that connects to the sewer system

cattle chute -- a temporary, protected lane for vehicular traffic

cobrahead -- a standard-issue, stainless-steel street light, 25 to 30 feet in height; the name refers to the lamp at the end of the pole (whose shape resembles the head of a cobra), though generally it includes the pole and arm as well

concrete base (or road base) -- a layer of concrete six to nine inches thick underneath the asphalt; the concrete base bears the weight of the vehicles on the road

curtain wall --the exterior wall or façade of a building, which does not bear any of the building load

Delta barrier -- a retractable barrier installed within a street to prevent or allow access; manufactured by Delta Scientific Corp. (seen around the New York Stock Exchange and Civic Center areas)

duct -- a small pipe through which electrical, telecommunications, and other smaller underground utility lines run; also known as a “conduit”

egress -- the motion of exiting; i.e., “There are many pedestrians on Church Street due to high-volume egress from the PATH station.”

engineered resurfacing -- the process of removing the asphalt wearing course from a street surface, examining the concrete base below for damage, making all necessary repairs, and laying a new asphalt wearing course

French barrier -- a fence-like, freestanding metal barricade, generally used for directing pedestrians

grade -- surface elevation; i.e., The subway is below grade.

house connection -- the secondary distribution and collection pipes for non-wired utilities, such as gas, steam, water, and sewer, that connect a structure to the mains

infrastructure -- the system of public utilities

Jersey barrier -- a solid-concrete, freestanding barricade; typically eight feet

long light-emiting diode (LED) -- a semiconductor diode that emits light and has an extremely long life span (typically 10 years), commonly used in electronic displays including citywide traffic signals

leading pedestrian interval (LPI) -- the timing of a “Walk” signal to allow pedestrians extra time to cross before the vehicular traffic signal turns green; currently in place along Church Street as part of the city’s Street Management Project

main -- the primary distribution and collection pipes for non-wired utilities, such as gas, steam, water, and sewer; typically 12 to 20 inches in diameter

milling and resurfacing -- the process of removing the asphalt wearing course using a machine that “mills” and disposes of the material and then laying a new asphalt wearing course

maintenance and protection of traffic (MPT) plan -- a plan for the various signs, markings, devices, and detours that are required to allow traffic, both vehicular and pedestrian, through a construction site

oculus -- a circular opening at the top of a rounded structure (seen in World Trade Center Transportation Hub and Fulton Street Transit Center designs)

particulate -- fine road and construction dust, diesel soot, and other visible and microscopic particles that are suspended in the air, typically a result of emissions from fossil-fuel burning, vehicles, and boilers

planter -- a more decorative piece of “street furniture” used in place of bollards and barricades; typically filled with flowers and greenery

plate -- a sheet of steel used to cover construction trenches and pits to allow traffic to flow when construction is not happening

ponding -- the collection of water at a low point of a paved surface

pontoon -- wooden beams laid side by side over street construction sites to open lanes of traffic

platoon -- the group of cars that collect and move through a traffic signal together

repointing -- the process of removing deteriorated mortar from the joints of a masonry wall and replacing it with new mortar

road base -- see concrete base

secant wall -- a wall created by first driving or screwing large hollow cylinders into ground, removing the earth within, and filling the cylinders with concrete to form solid piles. Then secondary cylinders are installed between the first piles, interlocking to form a sub-grade dam that holds back earth from an interior work site

sheep run -- a temporary, protected pedestrian walkway

sidewalk shed -- a structure built over the sidewalk and around the exterior of a building, while work is occurring on the building, to protect pedestrians from falling debris; also called a “sidewalk bridge”

slalom -- a zigzag course created by barricades

slurry wall -- the three-foot-thick concrete perimeter wall that forms the World Trade Center site’s east and west bathtubs, supported laterally by high-strength tieback anchors

steam flange -- the joint connecting two steam mains

superstructure -- the part of a building or structure above the foundations

test pit -- a patch of roadway opened to inspect underground utilities to identify potential conflicts between existing and proposed structures

temporary certificate of occupancy (TCO) -- a legal document that allows for a building’s temporary occupancy, pending final inspection

tieback -- an anchor drilled through the slurry wall into bedrock for lateral support

timber curb -- temporary, movable curbs made of painted wood, sometimes heightened to form upright barricades

traffic enforcement agent (TEA) -- a uniformed member of the NYPD who directs vehicular traffic, or engages in summons enforcement

trench -- a long cut in the ground, used commonly for water-main replacement and installation in place of capital street reconstructions

ultra-low-sulfur diesel (ULSD) -- a “clean diesel” fuel that reduces emissions of nitrogen oxides and particulate matter; one of the cleanest fuels available (New York City and State laws now require that non-road construction equipment used on city construction projects and by public agencies use ULSD.)

vault -- an open space beneath a sidewalk or street and usually attached to a building’s basement, sometimes used for utilities or storage space