Highways are a vital aspect of transportation for automobiles, for the high speeds permitted enable drivers to travel long distances in a relatively short amount of time. However, due to the heavy amount of traffic flowing at very fast speeds on the roads, merging on and off of highways can be dangerous. Gore areas are intended to help organize and protect traffic when cars are entering or exiting the highways.
When a driver is entering the highway, the entrance ramp gradually connects the car with the through lanes of the highway so the driver can safely merge with the traffic on the road. While driving on the ramp and merging onto the highway, on the driver's left there is often a wide triangle-shaped boundary created by white lines. This gap, known as the gore area, functions to separate the entrance ramp from the lanes of the highway and to indicate to the driver when it is safe or legal to switch lanes and join the other traffic on the road.
When a car is exiting the highway, the exit ramp often gradually veers to the side of the other lanes and rises above the highway to enable the drivers to safely exit. While the driver is traveling on the exit ramp and veering away from the highway, similar to the entrance ramp, to his left there is typically a wide triangular-shaped boundary marked by white lines. This is also referred to as a gore area, and the area also serves to help ensure safety by separating the exit ramp from the through lanes on the highway and by informing drivers of when they can safely merge on or off the exit ramp.
Each state and each highway system can establish different laws regarding whether cars can pass through the gore area of an entrance or exit ramp. When the triangle shape is outlined by only one solid white line on each side, it is usually legal to cut through the area to merge onto the through lanes of the highway with the rest of the traffic. If the triangle shape is created with two (double) white lines on each side, then it is illegal to cross through the gore area and into traffic until the area closes, the entrance ramp merges with the highway and only a single white line -- or a dashed line -- is present on the driver's left. Some gore areas are marked with signs that indicate to drivers whether or not it is legal to cross through the area. Furthermore, when there is an object in the gore area, such as an island or patch of grass, it is illegal to cross through that area.
Gore zones create a substantial gap between the entrance ramp and the lanes of the highway, and this gap impairs the visibility of the incoming cars and makes it difficult for the drivers to see the traffic on the highway. Thus, even if crossing a particular gore area is legal, it is often more safe to stay on the entrance ramp and not change lanes onto the highway until the gore area closes and the ramp merges your car onto the highway area.
Likewise, when driving on an exit ramp, it can be dangerous to suddenly cross through the gore area and back onto the lanes of the highway. Thus, even if you realize you should not be on the exit ramp, it is more safe to stay on the ramp and reenter the highway at another location. Also, if you realize too late that you should be on an exit ramp, it is dangerous to abruptly cut through the gore area to get to the ramp. Instead, you should stay on the highway and get off at the next exit.