Our Country is entering a very serious, dangerous, and complicated time in the transportation and infrastructure industry. Motorists are becoming increasingly more frustrated with travel delays that are caused by roadway maintenance projects and expect that free-flow traffic should occur 24 hours a day. Motorists now understand that commuting traffic typically occurs between 7–9 am and 4–7 pm during the week and has become a given. During other times of the day during the week, and throughout the weekends, motorists using our roads and bridges expect to be able to travel those roads and bridges in a relatively free-flow situation. They trust that the roadways are safe and sound – and that the bridges they are driving over will not fall down.
Unfortunately, the reality is that a very large percentage of bridges on the public road system in the United States are aging well beyond their expected 50-year life span. A substantial percentage of bridges are approaching 65 years old and, within the next few years, over 25% of the country’s bridges will be 65 years old and will have exceeded their 50-year lifespan by more than 15-20 years. Traffic Engineers and Transportation Planners, as well as others in the engineering profession, are going to be called upon time and time again to, very quickly, design road and bridge projects that will cause substantial delays to the motoring public once they begin reconstruction.
There was a point in time when only the travel lanes or the surface of the bridge needed to be reconstructed. That, in and of itself, created a challenge as it relates to maintaining traffic throughout the day and throughout the week. The challenge we now face as a country is vastly more difficult. Not only is the travel surface or the pavement of the bridges failing, but the substructure and the superstructure (the columns and the bridge piers and the steel) are beginning to fail at an alarming rate.
Once the superstructure begins to fail, it no longer becomes a resurfacing project; it becomes a complete reconstruction of a brand new bridge – requiring significantly more time and taxpayer dollars. In some instances, this can occur by building a parallel, relocated bridge with a parallel, relocated approach road. In many cases, and for a variety of reasons, building a parallel bridge structure and relocating approach roads is simply not going to be possible.
What will likely occur is entire bridge structures, or entire roads, will need to be closed for long periods of time. That means that, on major arterials and interstates, heavy volumes of traffic will need to be relocated on other roadways or parallel roads. Traffic will need to be detoured onto other roadways and Traffic Engineers and Transportation Planners will need to undertake highly complex and dramatic traffic engineering studies, capacity analyses, and simulations to determine the impact and to understand the delays that are going to be caused when traffic is re-routed.