Section 3.4 Signs, Signals, and Roadway Markings

SECTION 3.4

What information about a highway is encoded in its route number? Can you legally cross a single white line marking your lane? If two cars arrive at a stop-sign-controlled intersection at the same moment, which one has the right-of-way? A closer look at those familiar signs, signals, and markings that blanket our roadways will facilitate route planning and ease negotiation of unusual traffic situations.

This section is a summary of the AAA Foundation for Traffic Safety film,
"Signs, Signals and Roadway Markings."

Along the roadway, there are hundreds of images that help you find your way. Your job as a driver is to pick out the information that will help you arrive safely at your destination.

You get much of this information in the form of traffic control signs, signals, and markings. Recognizing these signs, signals, and markings can give you advanced notice of changes ahead -- such as merges, reductions in speed or upcoming intersections. Knowing what they mean allows you to anticipate and react to changing traffic conditions so you can drive more safely and smoothly.

This section will discuss the rules and underlying logic behind traffic signs, signals, and markings and why they are important to you.

Markings

The streets themselves communicate with their painted messages called markings.

There are two general rules about markings that tell you where you may and may not drive.

The first rule is that white lines are on the right side of each traffic lane and yellow lines are on the left.

The second rule is that solid, or unbroken, lines tell you where you may not pass or change lanes; dashed or broken lines permit you to pass or change lanes.

For example, on a two-lane road, the solid white line to the right marks the edge of the roadway. The yellow line on the left separates you from oncoming traffic.

A double solid yellow line on your left means that it is not legal for you or for oncoming traffic to pass. If there is a dashed and solid line together and the broken line is on your side of the road, you may pass traffic ahead of you if you can do so safely. However, opposing traffic is not allowed to pass the solid line.

A dashed yellow line on the left means that you and the opposing traffic may pass. If you decide to pass, make sure you have enough room to pass safely.

On multi-lane roads with medians, broken white lines usually separate the lanes of traffic going in the same direction. Solid yellow lines mark the left side of the road and solid white lines mark the right side.

Single solid white lines are used in several ways. When solid white lines separate lanes of traffic moving in the same direction, do not change lanes or pass. A white line is also used to mark the edge of the highway.

Short (dotted) white lines like this guide you through large complex intersections, or may indicate exit only lanes on a freeway.

Crosswalk lines are marked by solid white lines or various patterns. Always stop your vehicle before the crosswalk. At some intersection, especially in small towns or in residential areas, crosswalks may not be marked. You still must yield to pedestrians in the intersection.

In addition to lane markings, you will also often see reflectors. Again, white marks the right edge and yellow the left; these lane markings are especially helpful at night or when it is hard to see the edges of the road.

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