Highways, Signs, Signals and Pavement Markings: Highway Types and Interstate Numbering, Sign Shapes From the Octagon to the Pennant, Sign Colors Including Fluorescent Pink, Warning Signs, Regulatory Signs From Speed Limits to Slower Traffic Keep Right, the 200-Foot Shared Center Lane Rule, Guide, Service, Route and Incident Signs, Work Zone Devices, Barricade Stripes, Arrow Panels and Flaggers, Every Traffic Light and Arrow, Yellow and White Lines, Red Raised Markers, Railroad Markings, Stop Lines, Crosswalks, Directional Arrows and Roundabouts

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

Source: Louisiana Class D & E Driver's Guide (OMV, R08/25 edition), Chapter 2 "Highway Transportation System" (pages 17–21) and Chapter 3 "Signs, Traffic Lights, and Pavement Markings" (pages 22–37).

The highway transportation system

The system of people, vehicles and roads is managed by the OMV, law enforcement, traffic courts, highway and vehicle engineering, emergency response and public education. Crashes are the leading cause of death for ages 15 to 24; the fatality rate is about 1.18 deaths per 100 million miles, down from 4.7 forty years ago thanks to belts, air bags and safer vehicles; in 2018 a Louisiana crash happened every 3 minutes, a serious injury every 7 minutes and a death every 11 hours 22 minutes; and Louisiana's four leading causes of fatalities are alcohol, distraction, aggressive driving and lack of seat belt use. Road types include parish roads, state highways (LA 1), US highways (US 1), interstates (created in the 1950s under Eisenhower; even numbers run east-west and odd numbers north-south), expressways and freeways (divided, at least four lanes), toll roads, parkways, divided highways, limited-access highways (entry only at signed exits), partial-access and full-access highways. More than 50 percent of fatal and injury crashes happen at or near intersections, and the "golden rule" of driving is to treat others as you want to be treated.

Sign shapes and colors

Traffic control also comes from law enforcement, highway personnel and school crossing guards, whose directions you must obey. Shapes tell you the message before you can read it: the octagon is only for stop; the rectangle for regulatory signs such as speed limits, school zones and parking; the diamond for warnings, orange in construction zones and yellow for curves, side roads and traffic flow; the downward triangle only for yield; the sideways pennant for no-passing zones; the round yellow advance warning sign and the white crossbuck, which is regulatory with the same meaning as a yield sign, for railroads; the horizontal rectangle for guide, some warning and temporary signs; and other shapes for route markers. Colors: red stops or prohibits (stop, yield, Do Not Enter, Wrong Way); orange temporary traffic control; amber/yellow warning and school; black the background of One Way, night speed limit and truck signs and the lettering on light backgrounds; white most regulatory backgrounds; blue traveler services, information, emergency evacuation routes and parts of interstate markers, light blue for disability parking; green guide and information signs; fluorescent yellow-green pedestrian, bicycle and school warnings; brown recreational and cultural sites; fluorescent pink incident management such as hurricane or crash closures.

Warning signs

Warning signs, usually yellow diamonds with black symbols (fluorescent yellow for school and pedestrian signs), include Cross Road, Side Road, T-Intersection, Roundabout Ahead, Curvy Road, Right Curve, Sharp Right Turn, Series of Turns, Winding Road, Divided Highway Begins and Ends, Lane Ends, Merging Traffic, Road Entering Curve, Angled Side Road, Do Not Stop, Added Lane, School Crossing, School Bus Loading, Pedestrian Crossing, Slippery When Wet, Narrow Bridge or Underpass, Sharp Curve, Uneven Grade Crossing, Bicycle Crossing, Deer Crossing, Emergency Vehicle Crossing, No Passing Zone, Traffic Signal Ahead, Stop Sign Ahead, Advisory Speed Around Curve, Low Clearance, the two-way traffic reminder, and advisory speeds for ramps and exits.

Regulatory signs

Regulatory signs are square, rectangular or specially shaped, white with black, red or green, and a red circle and slash prohibits an action such as No Left Turn, No Right Turn or No U-Turn. Speed Limit signs give the maximum, to be driven only in ideal conditions, and sometimes a minimum you must meet on high-speed roads; slow for slippery roads, rain, snow, ice, fog and poor visibility. A School Speed Limit When Flashing sign applies only while flashing. Lane use control signs, sometimes with painted arrows, show Straight, Left Turn Only, Right Turn Only and Straight or Turn Right. The stop sign, red with white letters and eight sides, requires a stop behind the stop line or crosswalk, a look in all directions and a yield before entering; a 4-WAY, 3-WAY, 5-WAY or ALL-WAY plaque means every approach stops. The yield sign is a red-and-white downward triangle: slow and let traffic with the right-of-way cross first. Shared Center Lane Left Turn Only reserves the lane for left turns from either direction, never through traffic or passing, and you may not drive more than 200 feet in it. No Turn on Red means wait for green; Stop Here on Red marks the stop point, and without a No Turn on Red sign you may turn right after stopping and checking. Do Not Block Intersection forbids stopping, standing or parking in the intersection and entering it unless you can clear it. Left Turn Yield on Green allows the turn after yielding to oncoming traffic. One-Way arrows show the only direction. Do Not Pass marks a no-passing zone set by sight distance and hidden hazards; Pass with Care marks its end. Keep Right directs traffic right of a median, island or divider; Slower Traffic Keep Right tells slow drivers to use the right lane on multilane highways. Do Not Enter, a white bar in a red circle, guards wrong-way ramp openings, divided highway crossovers and one-way streets, and Wrong Way follows it on ramps and appears when you turn the wrong way into a one-way street, alley or driveway. A Highway Evacuation Route sign marks an emergency route. The railroad crossbuck stands at every public crossing and requires yielding to trains.

Guide, service, route and incident signs

Guide signs are green, brown or blue squares and rectangles giving intersecting roads, cities, points of interest and services. Destination signs, green or brown with white, give direction and distance to cities, airports and state and parish lines; if "Exit" is printed on the left side of an exit sign the ramp is on the left, on the right side the ramp is on the right, and left-exit signs may be yellow. Service signs are blue with white symbols for rest areas, gas, food, lodging, telephone and hospitals. Route signs show by shape and color whether a road is interstate, US, state, city, parish or local. Incident signs are temporary, fluorescent pink with black letters, warning of closures and detours for crashes, disasters or spills, and Louisiana's Move Over law requires slowing and changing lanes at a roadside incident.

Work zones

Orange signs warn of workers, machinery and barricades ahead; fines are double in construction zones. Devices include signs, barricades, drums, cones, tubes, arrow panels and flaggers, all basically orange. Signs such as Flagger Ahead (slow and be ready to stop), Workers Ahead (reduce speed and move away from workers) and Low Shoulder (a sharp drop; slow and steer firmly if you must leave the pavement) are mostly diamonds. Traffic patterns can change daily. Barricade stripes sloping down to the left mean bear left, down to the right mean bear right, and devices often carry lights at night. Flashing or sequential arrow panels steer traffic into open lanes. Flaggers in orange vests use red flags or stop/slow paddles.

Traffic signals

Signals are red, yellow and green from top to bottom, or red on the left when horizontal, with single lights at some locations. Steady green: go if clear, yielding to emergency vehicles and others; if stopped when it turns green, let crossing traffic clear; a left turn on green is allowed only when clear, yielding to oncoming traffic and pedestrians. Green arrow: turn in that direction if clear, while oncoming and crossing traffic should yield, watching for drivers turning right on red from the far side and for pedestrians. Steady yellow: the signal is about to turn red; slow and stop before the stop bar if you can, or continue through if already in the intersection. Flashing yellow: slow, look for entering traffic and proceed with caution, stopping if traffic is in the intersection. Steady yellow arrow: the green arrow is ending; prepare to stop and yield. Steady red: stop behind the stop bar, crosswalk or intersection until green; turn right on red after stopping and yielding unless a sign prohibits it, and left on red from a one-way onto a one-way where permitted, yielding to everyone. Flashing red: stop as at a stop sign, look both ways and yield. Red arrow: stop and do not go that way until the green arrow returns.

Pavement markings

Yellow center lines separate opposing traffic. A single broken yellow line marks a two-lane road; keep right of it and cross to turn or pass when safe. Double solid yellow lines mark the center of roads with four or more lanes; never cross them to pass, only to turn. A single solid yellow no-passing line on two-lane roads forbids passing but may be crossed to turn or when the dashed line is on your side. White lines separate same-direction lanes; all vehicles travel in the right lane except to prepare for a left turn, to pass or when right lanes are congested, no vehicle in the left lane may go slower than vehicles to its right, and anything slower than the normal speed of traffic stays right. A single solid white line means lane changing is hazardous, the wider the line the greater the hazard, and may be crossed only with great care; dashed white lines may be crossed when safe; white edge lines mark the right edge and yellow edge lines the left edge of divided roads; double solid white lines, common on interstates, may not be crossed. Red raised markers or reflectors mean you are going against traffic on a road you must not enter. Railroad markings are a large X and two Rs in the lane, a solid yellow center line preventing passing and a white stop line. A two-way left-turn lane, marked by solid and dashed yellow lines, is for left turns from either direction only, never travel or passing. Stop lines are solid white lines across the lane at intersections and crosswalks. Crosswalks are normally two solid white lines, sometimes with diagonal or longitudinal stripes; pedestrians in them have the right-of-way and you must stop, and mid-block crosswalks may carry a pedestrian crossing sign. Directional arrows or words require you to go only as shown, choosing any direction where several are marked; if you find yourself in a turn-only lane and want to go straight, make the turn and go around the block, because other drivers expect neither a sudden lane change nor a stop. In a roundabout traffic yields to circulating vehicles: slow to 15 mph or less, yield to the left before entering, never stop inside since the vehicle in the roundabout has the right-of-way, follow the destination signs, and when exiting look right, check the mirror and signal.

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