Roadway Signs, Traffic Signals and Pavement Markings

Written for aiforu2 as the source for a practice-test bank and the on-device tutor for the Illinois driver's license written exam. The facts follow the official manual; the wording is ours.

Source: Illinois Rules of the Road, Illinois Secretary of State, 2025 edition, chapter 9 "Roadway Signs" (pp. 64–77) and chapter 10 "Traffic Signals and Pavement Markings" (pp. 78–83).

Shapes and colors

The written exam asks you to identify signs. Eight sides, red: STOP, a complete stop at the stop line, else before the crosswalk, else before the intersection, yielding to pedestrians and traffic; wait your turn at an all-way stop; a temporary stop sign put up by highway authorities counts like a permanent one, and a handheld stop sign from a school guard or flagger means stop until they wave you on. Three sides (point down), red and white: YIELD, let all traffic and pedestrians go first. Round, yellow with a black X and RR: railroad crossing ahead, placed up to 750 feet before a rural crossing; slow, look, roll the windows down to listen, stop if needed, never race a train. Diamond, yellow, yellow-green or orange: warning. Five sides (pentagon), yellow or yellow-green: school zone or school crossing, the crossing version carrying a downward arrow. Sideways triangle (pennant), yellow: NO PASSING ZONE, on the left side at the start of the zone. Squares and rectangles serve as regulatory or guide signs.

Red signs are regulatory and must be obeyed (STOP, YIELD, DO NOT ENTER, WRONG WAY). Black and white signs are regulatory or route markers. Yellow warns of conditions and dangers; yellow-green warns of pedestrian and bicycle crossings, playgrounds, school bus stops and school zones; orange warns in construction and maintenance zones. Green guide signs give location, direction and distance; blue guide signs give services; brown marks parks and recreation; pink marks traffic incidents such as crashes and natural disasters.

Regulatory signs

Regulatory signs say what to do and must be obeyed: the all-way stop plaque (3-WAY, 5-WAY or ALL-WAY) means stop signs at every approach, first to stop goes first; YIELD also appears on expressway ramps without a merge lane, and there is no regulatory merging sign, only advisory and warning ones; DO NOT ENTER guards one-way streets and wrong-way ramp entries; SPEED ZONE AHEAD warns of a coming limit; SPEED LIMIT signs may show maximum and minimum limits on freeways, and driving below the minimum is illegal unless safety requires; WRONG WAY appears a short way past DO NOT ENTER on ramps and at wrong-way turns into one-way streets, alleys or driveways; a red circle with a slash from upper left to lower right forbids the pictured action; NO U-TURN signs stand at divided-highway openings reserved for police, ambulances, snow plows and maintenance vehicles; NO RIGHT/LEFT TURN; ONE WAY; two-way left turn lane signs (with yellow lines and white arrows); NO TURN ON RED (banning both right on red and left on red between one-way streets, sometimes with a red circle instead of the word); DIVIDED HIGHWAY ahead of a median-separated road you will turn onto or cross; KEEP RIGHT at islands and medians; SLOWER TRAFFIC KEEP RIGHT on multilane highways; STOP HERE ON RED where the stopping point is unclear; DO NOT PASS on two-lane roads, paired with yellow no-passing lines; PASS WITH CARE at the end of the zone; ROAD CLOSED to all traffic; and BIKE LANE, a lane marked by a solid white line that turns dotted before the corner, sometimes painted green.

Warning signs

Warning signs are usually yellow diamonds; some communities use fluorescent yellow-green for pedestrian, bicycle and school signs, and construction signs are orange. Pedestrian crosswalk signs mark crossings that may sit mid-block, sometimes with a yellow flashing beacon; other special crossing signs warn where vehicles and pedestrians cross. School signs warn of crossings ahead or school grounds, and the crosswalk versions stand at the crossing itself; adult crossing guards, auxiliary police and safety patrols may supervise; school speed zone signs apply on school days when children are present (usually 6:30 a.m. to 4 p.m.) or when the light flashes, and phone use is prohibited in a posted school speed zone. Stop ahead, yield ahead, signal ahead warn of controls not yet visible, especially in high-speed areas, so start slowing. Intersection signs: crossroad, side road, T and Y, sometimes with the cross road's name. Turn and curve signs show the shape of the bend (right and left turns, curves right and left, curve right, right turn, winding road), with an optional maximum safe speed plaque below. Exit ramp speed signs give the safe ramp speed. Slippery pavement: wet roads take longer to stop. Downgrade: a long or steep hill; slow before descending. Narrow bridge: the bridge is generally 2 feet narrower than the approach. Reduction in lanes: change lanes or let others merge; merge early when traffic is light and, when congested, use both lanes to the merge point and alternate, the zipper merge. Road narrows; the no passing pennant; merging lanes, where an expressway driver should slow to let the ramp driver in; change in direction chevrons on sharp curves and narrow bridge approaches; divided highway begins and ends; and two-way roadway ahead as a divided road ends.

Construction signs (orange) warn far enough ahead to adjust to the posted construction speed: workers ahead, cones, drums, barricades and vertical panels marking the path, warning lights at night, arrow boards showing a lane closure and which way to merge, flagger ahead (stop when signaled), and portable changeable message signs with real-time warnings, closures, delays, detours and zipper-merge instructions that must be followed. The slow-moving vehicle emblem means slow down and pass only when safe and legal; parking for persons with disabilities signs reserve spaces for disability plates, placards and Disabled Veteran plates. Guide signs are mostly rectangular, colored by the information they carry; route markers of different shapes name the road. Hazardous materials placards on vehicles, containers and packages use symbols, colors and text; at a placarded crash, evacuate as responders direct, or avoid the area and report it, and seek medical help if you feel ill, since exposure symptoms can be delayed.

Traffic signals

Signals and markings must be obeyed unless an officer directs otherwise, and you may never leave the roadway to avoid a signal. Lights run red, yellow, green from top to bottom or left to right, sometimes as a single light or arrows. Dark or broken signals mean an all-way stop: stop completely, look and yield before entering, unless police direct.

• Red: stop at the stop line, else before the crosswalk, else before the intersection, until green and clear. You may turn right on red unless a sign prohibits, and left on red from a one-way onto a one-way street with traffic moving left, in both cases after a complete stop and yielding to oncoming traffic and pedestrians.
• Yellow: the signal is changing to red; once red appears, do not enter.
• Green: go after yielding to pedestrians and vehicles in the intersection or crosswalk.
• Flashing red: stop, yield to traffic in the intersection or crosswalk, go when safe; used where a stop sign is hard to see and at railroad crossings.
• Flashing yellow: proceed with caution.
• Red arrow: no movement in that direction until a green arrow, with two exceptions: a right turn, and a left turn from a one-way onto a one-way street moving left, each after a complete stop and yielding.
• Steady yellow arrow: the green arrow is ending or the light is about to turn red.
• Flashing yellow arrow: turn that way after yielding to pedestrians and vehicles in the intersection or crosswalk.
• Green arrow: go in the arrow's direction (upward means straight only).

Pedestrian signals: pedestrians yield to drivers by obeying signals and using crosswalks. A walking person means cross in the signal's direction; a flashing upraised hand means do not start, but finish to a sidewalk or island if already crossing; a steady upraised hand means do not enter; a yellow light with an upraised hand means do not cross unless a sign or officer directs.

Lane signals over highway lanes change the flow at certain hours: a red X means never drive in the lane; a yellow X means the lane is about to turn red, leave it safely; a flashing yellow arrow means the lane may be used to approach and make a left turn; a green arrow means the lane is open, other signs and signals still applying.

Pavement markings

Edge lines: solid white on the right edge, solid yellow on the left edge of divided roads. White lane lines separate same-direction lanes: broken white may be crossed to change lanes or turn; solid white discourages crossing; double solid white may not be crossed. Yellow center lines separate opposite directions: broken yellow allows passing; double solid yellow may be crossed only to turn left into or out of an alley, private road, driveway or street. No-passing lines are solid yellow on your side of the center; you may cross one to finish a pass begun before the zone or to turn left into or from an alley, private road or driveway; with a solid and a broken yellow line together, pass only when the broken line is nearest your lane. Two-way left turn lanes are marked with yellow lines and white arrows; where one exists, left turns may not be made from any other lane, and the lane is used only to prepare for or make a left turn or a legal U-turn. A white stop line across the lane, usually 4 feet before the crosswalk in town, is where you stop for a sign or red light, before any part of the vehicle crosses it. White crosswalk lines span the pavement, sometimes with diagonal stripes, and pedestrians in them have the right-of-way; mid-block crosswalks carry a pedestrian crossing sign. Yellow or white diagonal stripes mark fixed obstructions, solid lines channel traffic around hazards, and local curb markings and fire lanes mark no-parking areas.

Railroad crossings are marked by the round advance warning sign (up to 750 feet ahead), pavement markings (a solid yellow no-passing line before the crossing and white stop lines on each side of the tracks), the crossbuck (with the number of tracks below when more than one), which is a yield sign for trains and railroad equipment, flashing lights (stop until the train has passed and the lights stop), and gates (stay stopped until they rise and the lights stop; never beat a lowering gate or go around a lowered one). Automated crossing cameras record violations, bringing fines and possible suspension. The Emergency Notification System sign at every crossing gives the railroad's number and the crossing identifier for emergencies.

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