Temporary traffic control strategy optimization for urban freeways

Temporary traffic control (TTC) strategies have been widely adopted to maintain traffic flow while ensuring TTC costs remain a reasonable portion of construction budgets. As travel demand approaches the capacity of an existing facility, implementation of an appropriate TTC strategy is increasingly important not only because lane closures on these facilities exacerbate existing delay, but also because speeds associated with congestion contribute disproportionately and non-linearly to roadway emissions produced throughout the lifetime of the roadway. To enable stakeholders to make informed and transparent decisions on selecting a TTC strategy so as to balance the trade-offs among construction cost, traffic delay, and energy consumption, this paper discusses the development of an integrated model that identifies the Pareto-optimal front when construction start time, construction duration, lateral clearance, and width of shoulder borrowed as a through lane are considered as decision variables. A test implementation of the model suggests that when construction budgets are low, strategies for decreasing traffic delay differ significantly from those for decreasing energy consumption; however, as construction budgets increase, the objectives on traffic delay and energy consumption align much better.