Common Myths about Bottlenecks

“Bottlenecks are caused only by not enough lanes on an extended highway section.”

In the past, recurring congestion was felt to be exclusively a systemic problem (e.g., not enough lanes, a system widening is the only solution), but often, clearing unique bottleneck locations within the system demonstrates that the uniform highway segments may not necessarily be underdesigned.

Traditional capital solutions often grew from the misconception that a multilane facility should be designed to alleviate the recurring peak hours each day. The problem is that funding for these large scale projects is limited, and right-of-way is often restricted, such that these projects take a long time (many years) to complete. As a result, recurring congestion historically went untreated, or at least competed against other worthy projects, until funding became available to “catch up” to the problem that had grown from the day the facility opened.

With a shift in the focus away from perceiving that recurring congestion is systemic (and thus treatable with only large projects), we must explore a wider-range of improvement strategies that are possible in the short-term. While these will never replace the need for corridor-wide fixes – especially at the "mega-bottlenecks" such as major freeway-to-freeway interchanges – bottleneck-specific improvements can provide congestion relief.

"Bottlenecks can't be fixed without massive reconstruction."

With the focus of transportation planners on major capital projects, it has been assumed for many years that bottlenecks cannot be fixed without massive reconstruction of an interchange or corridor. There are numerous examples where agencies opted to make lower-cost improvements that made significant improvement in traffic flow.

"Improving a bottleneck won't help traffic flow outside of peak periods."

Because traffic-influencing events like incidents, bad weather, work zones, and special events can happen at any time, congestion is not restricted to peak times of the day. The improvements made at bottlenecks primarily to address peak-period problems will carry over to the times outside of the peak when congestion occurs.