Illinois Road Signs Cheat Sheet.

Everything below is the highest-yield Illinois material compressed for a final pass. Read it the night before, again the morning of, and walk in with the shapes, colors, and numbers still warm.

Sign Shapes

• Octagon: stop. Red with white letters; no other sign borrows the shape.
• Downward triangle: yield. Slow, give way, stop if no gap opens.
• Yellow diamond, black symbol: warning of a condition ahead.
• Circle: railroad advance warning.
• Pentagon: school zone or school crossing.

Sign Colors

• Orange: construction or maintenance work zone.
• Blue: motorist services, including gas, food, and lodging.
• Brown: recreational and cultural destinations.

Pavement Markings

• Yellow lines: opposite-direction traffic on the other side.
• White lines: same-direction lanes.
• Solid yellow on your side: no passing for you.
• Broken lines: may be crossed when the way is clear.

Signals

• Flashing red: stop completely, then go when safe, exactly like a stop sign.
• Steady yellow: red is coming; stop if you safely can.
• Flashing yellow: slow down and proceed with caution.

Right-of-Way

• Four-way stop: first to arrive and stop goes first; simultaneous arrivals yield to the right.
• Left turn on plain green: yield to oncoming traffic.
• School bus with red lights and stop arm: both directions stop unless the highway has 4 or more lanes permitting opposite-direction travel.
• Illegally passing a stopped school bus: mandatory $300 fine, $1,000 the second time, plus community service.

Speed

• School zones: 20 mph on school days while children are present.
• Following distance: at least 3 seconds; add more when pavement is wet or icy.
• Posted limits are ceilings; conditions can make a lower speed the only lawful one.

Alcohol and Impairment

• Adult per se limit: 0.08.
• Commercial motor vehicles: 0.04.
• Under 21: zero tolerance; anything above 0.00 suspends the license.
• Implied consent: driving means consenting to chemical testing; refusal brings automatic suspension.
• Only time lowers alcohol concentration; coffee and showers only change how you feel.

Licensing Numbers

• Instruction permit: $20 for a first-time applicant, valid 24 months.
• Supervisor: age 21 or older with at least 1 year of driving experience, seated beside you.
• Practice: 50 certified hours behind the wheel, at least 10 at night.
• Graduated license: age 16 minimum, permit held at least 9 months.
• First 12 months or until 18: no more than 1 passenger under 20 unless immediate family.
• Original 4-year license: $30.

Test-Day Traps

• The 4-or-more-lanes exception to the school bus stop is the detail most often missed.
• A green light permits a left turn; it never grants priority over oncoming cars.
• Flashing red and flashing yellow are not twins: one stops you, one cautions you.
• Any answer built on adjusting to conditions usually beats any answer built on the posted number.