Evaluating the Impact of Bi-directional Traffic Flow on Urban Road Efficiency: A Case Study of Norwalk, CT, USA

Urban road efficiency is one of the most important facets of transport planning that holds huge implications for traffic flow rates, travel times, and overall mobility in urban areas. This study focuses on the influence of bi-directional traffic flow on urban road efficiency and takes Norwalk, CT as a case study. Arising from this, a holistic dataset with different traffic variables, such as average speed, vehicle delays, and free-flow factors was used to analyze the performance of bi-directional zones of the city's road network. From the analysis, bi-directional traffic zones have very varying efficiency levels, with average speeds ranging from 4 mph to 43 mph and very different vehicle delays. The median travel speed for these areas averaged 18 mph, which suggests moderate congestion. The average daily traffic volume was vastly different: some barely had any traffic, while others were as high as over 26,000 vehicles per day. The study also found that some of the variables used, like zone length and traffic volume, played a very important role in determining road efficiency; in most cases, longer zones and higher volumes increased delays and lowered speeds. Comparative and correlation analyses prove that, compared to the non-bi-directional zones, bi-directional zones generally sustain higher vehicle hours of delay. That is, as much as the bi-directional flow would accommodate traffic from both directions, under specific conditions, it contributes to congestion. Therefore, from the results, it follows that target-oriented traffic management strategies is required to optimize road efficiency in bi-directional zones, more so within an urban setup with constraints in space and infrastructure. The study concludes with several major recommendations to urban planners and traffic engineers for the adoption of context-specific solutions to making the road more efficient in bi-directional zones.