MEANING: You are approaching a hazardous location or a location where there is a special rule, as shown in the sample signs. Sometimes a warning sign is joined with a yellow and black "recommended speed" sign. This indicates reduced speed is advised in that area.

One solid line: You can pass other vehicles or change lanes, but you can only do so when obstructions in the road or traffic conditions make it necessary.

MEANING: Decrease speed as you reach the intersection. Prepare to stop and yield the right-of-way to vehicles and pedestrians in or heading toward the intersection. You must come to a full stop at a YIELD sign if traffic conditions require it. When you approach a YIELD sign, check carefully for traffic and be prepared to stop.

Green Arrow: You can go in the direction of the arrow, but you must yield the right-of-way to other traffic at the intersection as required by law (see Chapter 5).

Directions given by traffic officers take precedence over signs, signals or pavement markings. If a traffic officer signals you to stop at a green light, for example, you must stop. If an officer signals you to drive through a red light or stop sign, you must do it.

Arrows: Arrows show which lanes you must use. In this illustration, for example, you can turn right only from the right lane. To go straight, you must use the left lane. You must be in the correct lane before you reach the solid line that separates the lanes.

Some regulation signs have a red circle with a slash over a symbol. This indicates that an action, like a right turn, is not allowed or that some vehicles are restricted from the road. Rectangular white signs with black or red letters or symbols are indications to be alert for special rules.

Double solid lines: You can not pass or change lanes. You cannot go across the lines except to turn left to enter or leave the highway (e.g., to or from a driveway or to do a U-turn see Chapter 5).

You can make a right turn at a steady red light after you come to a full stop and yield the right-of-way to oncoming traffic and pedestrians. You can make a left turn at a steady red light when you turn from a one-way road into another one-way road after you come to a full stop and yield the right-of-way to oncoming traffic and pedestrians.

You cannot make a turn at a red light if there is a NO TURN ON RED sign posted or another sign, signal or pavement marking prevents the turn. You are not allowed to turn on a red light in New York City unless a sign that permits it is posted.

Stop and Crosswalk Lines: At an intersection controlled by a STOP sign, YIELD sign or traffic light, there can be a white stop line painted across the lane (called a Stop Line), and/or two parallel lines painted across the road (called a Crosswalk). When required to stop because of a sign or light, you must stop before you reach the stop line, if there is one, or the crosswalk. You need only stop at a stop line or crosswalk if required to by a light, sign or traffic officer, or to yield to a pedestrian, in-line skater or scooter at a marked or unmarked crosswalk. A single stop line may be placed at intersections to allow room for larger vehicles (such as tractor-trailers, buses and trucks) to turn without forcing other traffic to back up. It's important that you stop before you reach this stop line. (See "Pedestrians and Skateboarders" in Chapter 11).

MEANING: Come to a full stop, yield the right-of-way to vehicles and pedestrians in or heading toward the intersection. Go when it is safe. You must come to a stop before the stop line, if there is one. If not, you must stop before you enter the crosswalk. (See "Stop and Crosswalk Lines" under the "Pavement Markings" section of this chapter.) If there is no stop line or crosswalk, you must stop before you enter the intersection, at the point nearest the intersection that gives you a view of traffic on the intersecting roadway.

Yellow Arrow: The protection of a green arrow will end. If you intend to turn in the direction of the arrow, be prepared to stop.

Each state sets its own rules on campus security. Public schools are often permitted to hire sworn officers, while private schools face more restrictions. In California, for example, a private-school police officer has full enforcement powers only when he or she is working. (Public-school cops can make arrests 24 hours a day.) Virginia allows both public and private schools to set up sworn campus police departments.

Red Arrow: Do not go in the direction of the arrow until the red arrow light is off and a green light or arrow light goes on. A right or left turn on red is not permitted at a red arrow.

Lines that separate traffic that moves in opposite directions are yellow. There may be two lines between lanes and lines can be solid or broken. Read Chapter 6 for the rules on how to pass other vehicles.

Solid lines along the side of the road tell you where its edge is - where the travel lane ends and the shoulder begins. It is illegal to drive across the edge line, except when told to by a police officer or other authorized official or when allowed by an official sign. An edge line that angles toward the center of the road shows that the road is narrower ahead. Lines that separate lanes of traffic that moves in the same direction are white.

MEANING: These signs give information about rules for traffic direction, lane use, turns, speed, parking and other special requirements.

Steady Red: Stop. Do not go until the light is green. If a green arrow is shown with the red light, you can go toward the arrow and only if the intersection is clear.

Yale hired the first official campus cops in 1894 after a series of escalating town-gown conflicts in New Haven, Conn. But modern campus policing didn’t take shape until a surge in university enrollment after World War II made campus life more dangerous and unruly. Within a few decades, professional police departments were commonplace at large universities. According to statistics compiled by the Department of Justice in 1995, almost every school in America with more than 20,000 students employed sworn officers on campus. (Ninety-five percent used armed policemen.) Smaller, private schools were more likely to use hired security guards, but 43 percent had full-fledged cops.

Lines and symbols on the roadway divide lanes and tell you when you can pass other vehicles or change lanes. They also tell you which lanes to use for turns and where you must stop for signs or traffic signals. The arrows on these illustrations show the direction of traffic.

REGULATION SIGNS normally are white rectangles with black letters or symbols, but some are different shapes, and some can use red letters or symbols.

MEANING: People are at work on or near the roadway and traffic can be controlled by a flag person. A work area speed limit as low as 25 MPH (40 km/h) can be posted. Even if no speed limit is provided, you must drive at a reduced speed through the work zone and you must always obey the flag persons. These illustrations show some signals a flag person will use. Know and obey them.

The Virginia Tech police department comprises several dozen sworn officers and has received national accreditation from a private company known as the Commission on Accreditation for Law Enforcement Agencies Inc. (To get the CALEA seal of approval, a campus police department must demonstrate adherence to 459 standards—and fork over a few thousand dollars.) The Virginia Tech police Web site lists the department’s primary activities as “patrol, investigation, and crime prevention,” as well as answering “calls for assistance such as vehicle breakdowns or keys locked in vehicles.”

Among the persons authorized to direct traffic are police officers, fire police, highway work area flag persons, school crossing persons, and school bus drivers.

Before you move on to Chapter 5, make sure you can identify the signs in this chapter and know what they mean. Also, make sure you can answer these questions:

Explainer thanks Christopher Blake of the International Association of Campus Law Enforcement Administrators and Detective Sgt. Sally Miller of the Sonoma County Junior College District Police Department.

Note:  Practice quizzes are available only for those sections of the manual covering rules of the road (Chapters 4 through 11 and Road Signs).

It depends on the school. Most large colleges and universities set up full-fledged police departments on school grounds. These sworn officers have the same authority as any other members of the police—they carry weapons, make arrests, and enforce local, state, and federal laws. Smaller schools can contract out their security services to private firms, which supply the same sort of uniformed guards you might see at your local mall. Private security guards may be licensed to carry firearms, batons, or Tasers, but in general, they’ll be limited to making citizen’s arrests and detaining suspects until real police officers can arrive on the scene.

Traffic lights are normally red, yellow and green from the top to bottom or left to right. At some intersections, there are lone red, yellow or green lights. Some traffic lights are steady, others flash. Some are round, and some are arrows. State law requires that if the traffic lights or controls are out of service or does not operate correctly when you approach an intersection, you must come to a stop as you would for a stop sign. You must then continue according to the rules of right-of-way, unless you are told to continue by a traffic officer.

Traffic signs tell you about traffic rules, special hazards, where you are, how to get where you are going and where services are available.

MEANING: Indicate interstate, U.S., state or county routes. The shape tells you the type of route you are on. The sample signs, left to right, are for state, U.S., and interstate routes. When you plan a trip, use a highway map to decide which routes to take. During the trip, watch for destination signs so you will not get lost, or have to turn or stop suddenly.

Solid line with broken line: If you are on the side with the solid line, you cannot pass other vehicles or go across the line except to make a left turn into a driveway. If you are on the side with the broken line, you can pass if it is safe to and you will not interfere with traffic.

At least 33 people were killed in two separate shootings at Virginia Tech on Monday morning. The second round of violence began at 9:15 a.m., while campus police were still investigating the killings that happened two hours earlier. Are campus security officers just like real cops?

Diamond Symbol:  This symbol indicates reserved lanes for buses, HOV (High­ Occupancy Vehicles) like car-pools and van-pools, bicycles or other special vehicles. You cannot enter and use these lanes unless your vehicle complies with the occupancy or other requirements indicated by signs for the times the special conditions are in effect. When used to designate reserved lanes on city streets, sections of the solid white line that separates the diamond lanes from the normal lanes can be replaced by broken white lines. In these locations, non-HOV can enter the HOV lane if they make a right turn at the next intersection. Bus lanes and HOV lanes are to promote the most efficient use of limited street and highway capacity. They assure that vehicles with the highest importance move the fastest.