What’s the difference between traffic gridlock and a bottleneck?

In the vernacular of vehicular locomotion, a bottleneck is defined as congestion caused by more cars attempting to use a bridge or off-ramp at a rate greater than the infrastructure can handle. The result is that a line of slower-moving traffic forms. Gridlock occurs when the line formed by one bottleneck gives rise to another, which can in turn create more congestion.

A UC Berkeley transportation engineering student named Lewis Lehe examined the dynamics of traffic bottlenecks and published his results, along with an interactive tool, for his fellow roadway efficiency enthusiasts.