Escape Road :

Race tracks are designed to consider what happens when it goes wrong. On a purpose-built circuit, run-off areas and gravel traps are located in areas where cars may leave the track and need to kill speed to avoid the barriers

On a street circuit, typically, there is no room to install such features. Most of the track is lined with safety barriers that will punish the smallest of errors. 

An escape road is a feature used on street circuits to provide the driver with an option, other than hitting the wall, if he is not going to be able to slow sufficiently to make the corner

Andrew Burden

The author Kiwi F1 Fan