IMSA Work Zone flashcards
IMSA Work Zone · Build recall with a focused review session.
32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- TTC zone components
- Four sequential parts: advance warning area, transition area, activity area (buffer space, work space, and traffic space), and termination area.
- Merging taper formula (40 mph or less)
- L equals W times S, where W is the offset width in feet and S is the posted speed in mph.
- Merging taper formula (45 mph or more)
- L equals W times S squared divided by 60, where W is the offset width in feet and S is the posted speed in mph.
- Long-term stationary operation
- Work that occupies a location for more than three consecutive days and calls for the most durable and conspicuous device deployment.
- Short duration operation
- Work that occupies a location for up to one hour, allowing devices to be placed and removed as the crew advances.
- Traffic space
- The portion of the activity area through which road users travel; it must never be used for worker activities, storage, or equipment.
- Buffer space purpose
- A longitudinal separation between the work space and traffic flow that gives errant vehicles recovery room and shields workers.
- Work zone sign background color
- Orange is the standard background for warning signs in temporary traffic control zones, with black legend and black border.
- Cone height requirements
- At least 18 inches for daytime use at posted speeds of 45 mph or less; at least 28 inches for nighttime or higher-speed conditions.
- Drum characteristics
- At least 36 inches tall and 18 inches in diameter, with alternating retroreflective stripes, used for higher speeds or longer durations.
- Type III barricade
- A barricade with three horizontal rails used to close a road or ramp; it may carry a sign panel and warning lights.
- STOP/SLOW paddle
- A rigid octagonal paddle at least 18 inches wide used by flaggers to control traffic; it must be retroreflectorized and clean.
- Arrow panel size by speed
- A 48-inch panel is specified for posted speeds of 45 mph and above, while 36-inch panels serve lower-speed applications.
- Type B warning light
- A high-intensity flashing light used at night or in high-speed areas to draw attention to barricades, drums, or signs.
- Shifting taper length
- One-half the length of the merging taper for the same speed and offset, used where traffic is shifted laterally without narrowing.
- Shoulder taper length
- One-third of the merging taper length, used where only the shoulder is closed and the adjacent travel lane stays open.
- Downstream taper
- A 50- to 100-foot taper in the termination area that returns road users to the normal path after the work space.
- One-lane two-way taper
- A minimum 100-foot taper to the centerline where two-way traffic shares a single lane under flagger or signal control.
- Activity area definition
- The section where work occurs, consisting of buffer space, work space, and traffic space; road users travel only within traffic space.
- Advance warning area
- The first TTC zone component; its length increases with posted speed and it holds the signs that alert drivers before the taper.
- Flagger station position
- Placed on the shoulder ahead of the work space, with clear sight distance to approaching traffic and a safe escape route.
- High-visibility apparel class
- ANSI/ISEA 107 Class 2 or 3 apparel is required for workers; Class 3 is required during nighttime operations.
- Work zone fatality share
- Approximately 80 to 85 percent of work zone fatalities are vehicle occupants rather than workers, making road users the priority audience.
- Positive protection
- Physical separation such as temporary barriers or an attenuator truck that prevents errant vehicles from entering the work space.
- Truck-mounted attenuator
- A crash cushion mounted on a shadow vehicle positioned upstream of the taper to absorb impacts and shield the crew.
- Flagger escape route
- A pre-planned path the flagger can use to step clear of errant vehicles without entering another open lane.
- Standard MUTCD statement
- A mandatory condition; compliance is required and it governs traffic control device design, installation, and operation.
- Guidance MUTCD statement
- A recommended practice that should be followed unless engineering judgment identifies a better approach for the site.
- Night inspection purpose
- Verifying retroreflectivity, warning-light operation, and sign legibility under actual or simulated nighttime driving conditions.
- TTC documentation record
- The plan, daily inspection log, photographs, and device inventory retained to show the zone matched its approved layout.
- Inspection frequency trigger
- Inspect at the start of each shift and after any change in weather, traffic, or work activity that alters the layout.
- Inspection documentation content
- Record the date, time, inspector, devices checked, deficiencies found, and the time each correction was completed.