Signals, Signs and Pavement Markings

Written for aiforu2 as the source for a practice-test bank and the on-device tutor for the Pennsylvania non-commercial Class C knowledge test. The facts follow the official manual; the wording is ours.

Source: Pennsylvania Driver's Manual (PUB 95), Pennsylvania Department of Transportation, chapter 2 "Signals, Signs and Pavement Markings" (pp. 7–22).

Traffic signals

Signals are arranged vertically, red on top and green at the bottom, or horizontally, red on the left and green on the right.

• Steady red: stop before the stop line or crosswalk, or before the intersection if there are no lines, and wait for green. You may turn right on red after stopping and yielding to pedestrians and traffic, unless a NO TURN ON RED sign is posted, and turn left on red from the left lane of a one-way street onto another one-way street after stopping and yielding, unless a sign prohibits it.
• Steady yellow: red is coming; slow down and prepare to stop. If you are already in the intersection or cannot stop safely, continue through carefully.
• Steady green: go if the road is clear; you may turn right or left unless a sign forbids it, yielding to vehicles and pedestrians in the intersection.
• Steady red arrow: stop and do not turn that way; wait for a green arrow or a flashing yellow arrow. The same turns on red allowed at a steady red light are allowed at a red arrow.
• Steady yellow arrow: the movement allowed by the green or flashing yellow arrow is ending; slow and prepare to stop before the intersection, or finish a turn already begun with caution.
• Steady green arrow: turn the way it points; the turn is protected because oncoming traffic has a red. If the arrow becomes a green light you may still turn, but yield first.
• Flashing red: the same as a STOP sign: stop completely, look both ways, go when clear.
• Flashing yellow: caution; slow down, look and proceed with care.
• Flashing yellow arrow: you may turn that way with caution after yielding to oncoming traffic and pedestrians; the turn is not protected, since oncoming traffic has a green.
• Non-functioning signal: treat the intersection as a four-way STOP.
• Ramp-metering signals at the end of entrance ramps alternate steady red and green in rush hours to pace traffic onto congested highways; wait for green, one car per green on a single-lane ramp (one meter per lane on multi-lane ramps), and still look for a safe gap, since green does not protect your entry.

Lane-use control signals over lanes (at toll booths, bridges, tunnels, and reversible city lanes): a steady downward green arrow means the lane is yours; a steady yellow X means leave the lane, its direction is about to reverse; a steady red X means the lane is closed to you; a white steady one-way left-turn arrow means left turns only from that lane; a white two-way left-turn arrow means left turns only, in a lane shared with left-turners from the opposite direction.

Pedestrian, school zone and railroad signals

Pedestrians obey the WALK / DON'T WALK lights or the walking person and raised hand, and where there are none, the traffic lights. A steady WALK means start crossing but watch for turning vehicles; a flashing DON'T WALK means finish crossing if you are in the street and do not start if you are still on the curb; a steady DON'T WALK means do not cross. Always yield to pedestrians, since some ignore signals. Near a blind pedestrian with a white cane or guide dog, slow down, always yield, proceed with caution and be ready to stop.

School zone signals are flashing yellow lights on the school zone speed limit sign: no faster than 15 mph while they flash or during the posted times; speeding in a school zone costs three points plus a fine.

Railroad crossings: approach with caution, look both ways and listen. You must stop when a train is signaled by flashing red lights, a lowered gate, a flagger, or the train's horn, and never go around a gate or ignore a signal; with no signals, slow down and prepare to stop if you see or hear a train. Proceed only after all signals finish and no train is coming; stop when a train has sounded or is plainly visible and dangerously close. Never stop on the tracks: if traffic backs up from a signal or stop sign, stop entirely clear of them.

Regulatory signs

Regulatory signs say what you must or must not do, and disobeying them means fines and points. Most are black-and-white vertical rectangles or squares (SPEED LIMIT), some black, white and red (NO LEFT TURN with a circle and slash), and some red and white (STOP, YIELD, DO NOT ENTER, WRONG WAY).

• STOP: the only octagon. Stop completely, check pedestrians and cross traffic, and go when clear; slowing without a full stop is illegal. Stop before the front of the vehicle reaches the first painted line of a crosswalk or stop line; if you cannot see, yield to pedestrians, then edge forward past the line until you can. An EXCEPT RIGHT TURN plaque under a stop sign lets you turn right without stopping.
• 4-WAY plaque: all four directions stop; the first to arrive goes first; two arriving together, the driver on the left yields to the right; facing each other, both may go with caution, watching for turns.
• YIELD: the triangle. Slow, check traffic, give the right-of-way to pedestrians and approaching cross traffic, stopping only when necessary, and go when you will not interfere with traffic. An ONE LANE BRIDGE plaque with a yield sign means yield to opposing traffic on the one-lane bridge or underpass.
• Railroad crossbuck: treat as a YIELD sign; slow and prepare to stop if a train is coming.
• DO NOT ENTER stands at the start of one-way streets and ramps; WRONG WAY signs farther along catch you if you entered by mistake. ONE WAY allows traffic only in the arrow's direction; entering against it invites a head-on crash.
• DIVIDED HIGHWAY (regulatory): your road meets a divided highway, two one-way roads split by a median or guide rail; at the first roadway you may only turn right, at the second only left.
• NO TRUCKS, NO BICYCLES, NO PEDESTRIAN CROSSING: those users may not use the road. NO U-TURN, NO RIGHT TURN, NO LEFT TURN: the movement is prohibited. NO PARKING: no parking where posted. DO NOT PASS: no passing vehicles going your way, often paired with the pennant NO PASSING ZONE.
• Lane-use control signs over a lane show what that lane may do; with a turn arrow and the word ONLY you must make that turn, even if you entered the lane by mistake. CENTER LANE LEFT TURN ONLY: the lane is reserved for left turns from either direction, never for through traffic or passing. KEEP RIGHT: stay right of the island or divider. RIGHT TURN SIGNAL: the nearby signal controls right turns.
• SPEED LIMIT: the maximum under ideal conditions; driving too fast for conditions is the number one cause of crashes among 16- and 17-year-old drivers.
• NO TURN ON RED: wait for green. LEFT TURN YIELD ON FLASHING YELLOW ARROW and LEFT TURN YIELD ON GREEN: the left turn is allowed but not protected; yield to oncoming traffic. LEFT TURN, OPPOSING TRAFFIC HAS EXTENDED GREEN: oncoming traffic may keep moving after your light turns red.
• RESERVED PARKING (blue, but regulatory): for disabled persons or severely disabled veterans with the authorized plate or placard; others are fined and towed.

Warning signs

Warning signs, usually yellow diamonds with black symbols, describe a condition ahead in time to react.

• NO PASSING ZONE: the only pennant, on the left side of the road, marking the start of a no-passing zone.
• Chevrons: a sharp change of direction; the road bends the way they point.
• Left / right curve: slow down; through a left curve stay centered in your lane, through a right curve keep slightly right of center. Sharp turn: slow substantially; an advisory speed may be shown. Set of curves, right and left sharp turns, winding road (three or more curves): slow and prepare.
• One-direction large arrow: an extreme change of direction; slow as for a turn at an intersection.
• Road entering curve: the main road bends left as a side road enters from the right; a driver entering may not see you around the curve.
• Truck rollover: a curve where speeding trucks can roll.
• Advisory speed plaque under any warning diamond: the highest safe speed, for example 25 mph for the curve ahead.
• Merging traffic: traffic joins your lane from a road or ramp, and it must yield to you. Added lane: no merge needed; entering traffic gets its own new lane. Weave area: you merge with another road while some traffic exits across your path.
• Divided highway begins / ends, two-way traffic ahead: keep right of the divider or center line and watch for oncoming traffic. Lane ends / merge left: the right lane ends; merge left.
• Intersection signs: cross road, side road, T, Y and circular intersections; the two-direction large arrow at the far side of a T says you can only go left or right.
• Narrow bridge or underpass: lanes narrow with no shoulder; slow, stay in your lane, and wait if an oncoming vehicle is wide.
• Slippery when wet: slow down, lengthen following distance, no sudden acceleration or braking, turn very slowly.
• Deer crossing, low clearance (do not enter if taller than the height shown), low shoulder (up to three inches below the road) and shoulder drop-off (worse): if a wheel drops off, do not brake hard or steer sharply back.
• Hill/downgrade: slow and be ready to shift to a lower gear to save the brakes.
• Traffic signal ahead and stop sign ahead: the control may be hidden by a curve or hill and a line of vehicles may be stopped; slow and prepare to stop.
• Bicycle crossing, pedestrian crossing (yellow or fluorescent yellow-green), railroad crossing ahead (start looking and listening), advanced intersection/railroad crossing (the cross road has tracks just beyond the intersection), SHARE THE ROAD at pinch points, horse-drawn vehicle, and SCHOOL, the only pentagon, with a downward arrow when at the school crosswalk itself.
• Object markers: striped panels at bridge ends, underpass supports and guide rails, with the stripes angled down toward the side you should move to (right hazard: keep left; left hazard: keep right; center hazard: either side).

Work zone signs

Work zone signs are orange diamonds with black lettering marking maintenance, construction and utility areas. Turn on your headlights in every posted work zone, active or not, day or night; a driver stopped for a violation in a work zone without headlights pays an extra $25. ACTIVE WORK ZONE WHEN FLASHING and END ACTIVE WORK ZONE signs bracket the stretch where workers are on the road or on the shoulder beside an open lane, where penalties increase. Other signs: ROAD CLOSED FLOODING (use another route), ROAD WORK AHEAD, LANE CLOSED AHEAD with a distance, WORKERS AHEAD, and FLAGGER AHEAD; flaggers use STOP and SLOW paddles or a red flag. Highway workers can report unsafe drivers to police for tickets. Electric arrow panels say move or merge right or left (begin early) or show a caution pattern for work beside the lane; barrels, tubes, cones and vertical panels channel you through the changed pattern.

Guide signs

Guide signs, usually horizontal rectangles, name intersecting roads, destinations, points of interest and services. Highway guide signs are green with white letters and come in threes: two advance signs and one at the exit, because speed and traffic make a single sign easy to miss. Exit numbers match the mile markers, so Exit 95 to Exit 20 is 75 miles. A yellow EXIT ONLY panel means that lane leaves the highway; change lanes or exit. The small EXIT number tab sits on the left of the sign when the exit is on the left and on the right when it is on the right, and white arrows point toward the exit.

Interstate numbering: the red, white and blue shield. One- or two-digit even numbers run east-west, increasing from I-10 in the south to I-94 in the north (I-76 in southern Pennsylvania, I-80 and I-84 in the north); odd numbers run north-south, increasing from I-5 in the west to I-95 in the east (I-79 west, I-95 east). Three-digit routes connect to other highways: a first digit that is even usually joins interstates at both ends, a loop or beltway such as I-276; an odd first digit is a spur joining at one end, such as I-180. Mile markers count from where the route enters the state, from zero in the west for east-west roads and in the south for north-south roads, rising as you go east or north; they tell you where you are for roadside assistance.

Route markers: the U.S. route shield (U.S. 22), the keystone for a Pennsylvania route (PA 39), with JCT, direction (WEST) and arrow plates, and a TO trailblazer meaning continue ahead to reach that route. Service signs are blue with white symbols (hospital, phone, food, gas, diesel, lodging) for the next exit; tourist-oriented signs are blue or brown.

Pavement markings

Yellow lines divide opposite directions: the center of two-lane roads and the left edge of divided highways, one-way streets and ramps. White lines divide lanes going the same way and mark the right edge. Broken lines may be crossed; solid lines may not, except to turn.

• Single broken yellow center line: passing allowed from either side when safe, using the oncoming lane.
• Double solid yellow: no passing in either direction, sign or no sign.
• Solid beside broken yellow: pass only when the broken line is on your side.
• Three- or five-lane roads: the outer solid yellow means the center lane is not for passing; the inner broken-and-solid pair means either direction may use the center lane only for left turns.
• Multi-lane road without a median: cross broken white lines to pass when clear, never the double yellow; the lane left of the yellow carries oncoming traffic.
• Limited access highways with medians: solid white right edge, solid yellow left edge, broken white lane lines that may be crossed.
• Painted words and arrows reinforce signs: STOP AHEAD, YIELD or white triangles across the lane, SCHOOL, R X R before a crossing, BIKE LANE, ONLY with a turn arrow, and large white arrows showing the direction on one-way streets and off-ramps.

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