Signals, Signs and Markings: Traffic Lights, Sign Colors and Shapes, Pavement Markings and Work Zones

Written for aiforu2 as the source for a practice-test bank and the on-device tutor for the Texas Class C knowledge exam. The facts follow the official handbook; the wording is ours.

Source: Texas Driver Handbook (DL-7), Texas Department of Public Safety, rev. January 2026, chapter 5 "Signals, Signs, and Markers" (pp. 25–37).

Traffic signals

Signals keep traffic orderly and must be obeyed, with one exception: a law enforcement officer directing traffic overrides every signal, even when the officer tells you to do something that is normally against the law.

• Steady red: stop before the crosswalk or intersection. You may turn right on red unless a sign prohibits it, and turn left on red when both streets are one-way, unless prohibited; either way, yield to pedestrians and to traffic lawfully in the intersection.
• Flashing red: come to a complete stop, then go when safe. Traffic on the cross street may not have to stop.
• Steady yellow: the light is about to turn red. Stop before the nearest crosswalk if you can do so safely; if you cannot stop safely, continue through with caution before the red.
• Flashing yellow: slow down and proceed with caution.
• Flashing yellow arrow: you may turn left, but you must yield to oncoming traffic.
• Steady green: go if it is safe, straight or turning unless a sign or signal prohibits it. Watch for vehicles and pedestrians still in the intersection and for drivers racing to beat the red.
• Green arrow with a red light: proceed carefully in the direction of the arrow after yielding to other vehicles and pedestrians. A green arrow gives a protected left turn: oncoming traffic has a red, but turn with caution.
• Left turn on a plain green: allowed, after yielding to all traffic approaching from the opposite direction.

Lane-use control signals hang over individual lanes on streets or highways: a red X means do not drive in that lane; a steady yellow X means prepare to leave the lane safely, because the lane control is changing; a steady downward green arrow means the lane is open to you.

What signs do, and their colors and shapes

Signs warn of hazards that are hard to see, guide you to your destination by identifying the route, inform you of local regulations, and regulate speed and movement.

Shapes tell you what to do before you can read the sign:

Warning signs

Warning signs, yellow diamonds, tell you what is immediately ahead: a hazard, a change of direction, or another condition to prepare for. Ignoring one can be a traffic violation as well as dangerous. When you see one: pay attention, follow its instructions, and reduce speed at least to any posted advisory speed.

Common warning signs and what to do:

• Signal ahead: a traffic signal is coming; be ready to stop.
• Low clearance: the height shown is the clearance of the underpass; do not enter if your load is taller.
• Divided highway begins: opposing traffic will be separated by a median island. Divided highway ends: two-way traffic resumes; be careful at the point where it begins.
• Added lane: two roads come together and a new lane begins; you need not merge, but watch traffic in the new lane. Merge: other traffic lanes join yours; watch for traffic from that side. Lane ends: the lane ends ahead, and a driver in the right lane should merge left. Lane reduction signs give advance notice that the number of lanes is dropping.
• Slippery when wet: slow down on a wet road; do not turn, speed up or stop suddenly.
• Winding road: drive slowly and carefully; do not pass. Curve (a gradual bend), turn (a sharp bend), reverse curve and reverse turn (one way then the other): slow down, keep right, do not pass. Chevrons and large arrows mark the alignment of a sharp curve as an aid at night.
• Two-way traffic: drive in the right lane and expect oncoming traffic in the left lane.
• Side road, crossroad, T-intersection (you must turn left or right, and may need to yield) and Y-intersection: slow down and watch for traffic from the joining road. Where your road meets a highway, slow down, look right and left and be ready to stop.
• Rough road: the surface ahead is in poor condition; slow down. Dip: a low place; slow to avoid losing control or a jolt. Bump: a sudden high place; slow down likewise.
• Soft shoulder: use extreme caution not to leave the pavement, because the dirt beside it is soft and can make you lose control. Shoulder drop-off: a big drop from the pavement edge to the shoulder; if you must leave the pavement, slow down and steer firmly.
• Pedestrian crossing: many people cross here; slow down and watch. School: slow down, watch for children, be ready to stop suddenly. Disabled crossing: watch for people who may be disabled or in a wheelchair.
• Narrow bridge: the bridge is narrower than the road; slow down. Pavement narrows: proceed with caution. Pavement ends: the hard surface changes to earth or a low-type surface; slow down.
• Loose gravel: go slowly enough to keep control; no sudden braking or sharp turns. Grooved pavement: grooves lessen slipperiness in the wet; motorcyclists take care.
• Bridge ices before road: displayed all winter; slow down and avoid sudden braking or sharp moves.
• Hill (downgrade): approach with caution; a lower gear may be needed.
• Object markers stand in front of obstructions near the road edge, such as culverts or bridge piers, or mark the ends of narrow bridge rails; a double arrow means traffic may pass on either side of an island or obstruction.
• Ramp meter ahead: yellow lights flash on the sign when the freeway ramp ahead is metered; the ramp signal (red or green) tells you when to enter.
• Truck crossing: slow down and watch for trucks entering or crossing. Deer crossing: slow down, stay alert, be ready to stop if animals appear.
• Stop ahead: be prepared for a stop sign ahead.

Regulatory signs

Regulatory signs say what you must or must not do, and carry the force of law.

• Stop: red with white letters (or yellow with black). Come to a complete stop before the crosswalk, intersection or sign, yield to pedestrians and vehicles, then proceed carefully. Slowing down is not enough, and the rule applies to each vehicle that reaches the sign. All Way plaques mean every approach stops and goes in order of arrival; two arriving together, the one on the right goes first.
• Yield: the road ahead joins another; slow or stop as needed to yield to vehicles, pedestrians and bicycles on the other road.
• Speed limit: the maximum in mph; some signs give separate day and night limits. Advisory speed plaques below a warning sign give the highest safe speed for the curve or turn ahead; exit speed signs do the same for a ramp.
• Turn-direction arrows: at an intersection with this sign, turn only in the direction shown. Right lane must turn right: traffic in the right lane turns right at the next intersection unless the sign names another point. Two-lane left turn: the left lane must turn left; the next lane may turn or go straight.
• No left turn, No U-turn, No right turn: the movement is prohibited at that intersection.
• Do not pass and Do not cross yellow lines: sight distance is too short to pass safely.
• Slower traffic keep right: if you are slower than the others, stay in the right-hand lane. Left lane for passing only: on a multi-lane road, slower traffic uses a lane other than the far left one.
• Center lane left turn only: the center lane is only for vehicles turning left, never for passing or through traffic; enter it only where you have room to slow or stop for a safe left turn.
• Do not change lanes or turn across double white lines.
• Wrong way: if it faces you, you are driving against traffic on a one-way street. Do Not Enter: the road ahead carries one-way traffic toward you.
• Keep right: drive to the right of the sign, used ahead of islands and medians. Crossover: a place to cross to the other side of a divided highway.
• No trucks: trucks may not use or enter the road.
• HOV lane: buses and carpools only, during the posted hours (for example 6 to 9 a.m., Monday through Friday).
• Disabled parking: do not park, stop or stand there without a disabled plate or windshield placard.
• School zone speed: the speed shown applies when the yellow light is flashing; be extremely careful. No wireless devices may be used in a posted school zone.
• Photo enforced: the red light is camera-enforced.
• Emergency stopping only: the shoulder is only for breakdowns, tire trouble, running out of fuel and other emergencies.
• Road closed: not open to any traffic; find a detour. Merge into one lane: all traffic on the roadway must form a single lane.

Guide, route and service signs

Guide signs (mostly green) tell you where you are and how to get where you are going. Route markers name the road: the red-white-and-blue shield is an Interstate, the black-and-white shield a U.S. route, and the Texas marker a state highway; a spur is a short state highway in a city, and a business route branches off the numbered highway through the business part of a town. Destination and distance signs give the way and mileage to cities, airports and other places. Overhead signs with arrows show which lane follows which route; an Exit Only panel means the lane under it leaves the highway. Mileposts stand every mile on Interstates so you can report the location of a crash or breakdown. A litter barrel sign says a barrel is one mile ahead, the only lawful place to throw trash on the highway; barrels are at every rest and picnic area too. Blue signs advertise services such as gas and hospitals.

Railroad signs and crossings

• Railroad advance warning (the round yellow sign): you are within a few hundred feet of a crossing; slow down and be ready to stop, and if a train is coming, stop. Never try to beat a train.
• Crossbuck: posted at every crossing, showing where the tracks are; a plaque gives the number of tracks if more than one. Slow down, look, listen, and be ready to yield to a train.
• Emergency Notification System sign: the railroad's emergency number and the USDOT crossing inventory number, for reporting stalled vehicles, broken signals and other emergencies.
• Gates and flashing lights: stop when the lights begin to flash, before the gate lowers across your side; stay stopped until the gates rise and the lights stop. Stop 15 to 50 feet from the nearest rail when a flagger directs you, when red lights flash or bells sound, or when any device warns of a train.

Pavement markings

• Two-lane road, two-way traffic: keep right of the yellow center line. You may cross a broken line to pass or when the right half of the road is closed; never cross a solid yellow line or when it is unsafe.
• Solid and broken lines: a solid yellow line on your side marks a no-passing zone; broken lines let you pass or change lanes when safe.
• Three-lane one-way road: with broken white lines you may drive in any lane; before turning off a one-way street, move well ahead of time into the lane closest to the turn.
• Center left-turn lane: enter only where you have room to slow or stop for a safe left turn; never use it for passing or through traffic.
• Multi-lane highway (four or more lanes): do not cross the double yellow line to pass; stay in your lane; slower drivers keep right.
• Crosswalks: white lines across the road mark where pedestrians cross. Where there is no stop line, stop before the crosswalk when a sign, signal or pedestrian requires it.
• White stop lines: stop behind the line at signs and signals.
• Solid white lines mark pavement edges, shoulders, channelizing, transitions and lane use; avoid crossing them. Double solid white lines may not be crossed. A solid yellow line on the left edge, seen on Interstates, means driving to its left is prohibited.
• Barrels built as impact cushions stand in front of solid obstacles and at high-crash spots to soften a collision.
• A hearing-impaired flag on a bicycle, or the sign on a vehicle, means the rider or driver may not hear you; slow down.

Construction and maintenance zones

Work zones use signs, barricades, vertical panels, drums, cones, tubes, flashing arrow panels and flaggers, and their basic color is orange. Most work-zone signs are diamonds, a few rectangles. Be prepared to slow or stop near workers and equipment, to change lanes, and for unexpected movements. Fines double for violations in a work zone when workers are present.

Channelizing devices (barricades, panels, drums, cones, tubes), often lit at night, guide you through: slow down and prepare to change lanes when safe; expect drivers who wait until the last second to move over; keep the reduced speed until the sign says the zone has ended; and return to the normal lane only after checking behind you. On a barricade or panel, stripes sloping down to the right mean bear right; stripes sloping down to the left mean bear left. Flashing arrow panels steer you into particular lanes and say part of the road ahead is closed.

A flagger, in an orange vest, shirt or jacket, uses STOP/SLOW paddles or red flags where the hazard is extreme. Obey the flagger: stop in your lane without veering, do not move until told, proceed with caution, and watch for oncoming vehicles in your lane. An automated flagger assistance device (AFAD) is remotely operated so the flagger can stand out of the traffic lane; pilot vehicles, advance signs and temporary signals are also used.

Disobeying a warning sign or driving around a barricade is a misdemeanor with a fine of $1 to $200 (doubled in a work zone with workers present). Where the sign or barricade marks water over the road, it is a Class B misdemeanor: up to $2,000 and/or up to 180 days in jail.

Slow-moving vehicle emblem

The orange triangle is required on every vehicle designed for 25 mph or less, including farm and road machinery and anything drawn by animals or slow vehicles, and it is prohibited on anything else, including stationary objects. Exceptions: a vehicle working inside a marked construction zone, and a towed implement when the towing vehicle's emblem stays visible.

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