Transportation is often misunderstood to be the defining characteristic, or even the sole purpose, of a street. This has not been the case since the word "street" came to be limited to urban situations, and even in the automobile age, is still demonstrably false. A street may be temporarily blocked to all through traffic in order to secure the space for other uses, such as a street fair, a flea market, children at play, filming a movie, or construction work. Many streets are bracketed by bollards or Jersey barriers so as to keep out vehicles. These measures are often taken in a city's busiest areas, the "destination" districts, when the volume of activity outgrows the capacity of private passenger vehicles to support it. A feature universal to all streets is a human-scale design that gives its users the space and security to feel engaged in their surroundings, whatever through traffic may pass.