Performance and efficiency of direct connectors and assessment of impact on frontage roads

This study provides evidence of the performance and efficiency of using direct connectors in an interchange based on delay and travel times for selected travel sections using microscopic simulation and crash analyses. The direct connectors play a major role in shifting the traffic from one freeway to the other effectively without obstruction and are used to reduce travel distance, increase capacity and speed. The absence of direct connectors at a two-freeway intersection also impacts the performance of frontage roads especially when such interchanges are present within cities. This study also discusses the influence of direct connectors on existing frontage roads around interchanges. The results were analyzed and compared using crash analysis and delay times to evaluate the efficiency of direct connectors using a case study on a proposed interchange design between the existing Interstate Highway 37(IH-37) and newly proposed U.S. Highway 181 (US-181) in the city of Corpus Christi, Texas. The density and flow of traffic are predicted to increase in the future due to the emergence of proposed US-181 at IH-37 and Crosstown Expressway interchange especially toward the IH-37 east that is toward the downtown area. The increase in daily traffic on the proposed design of grade separated interchange may cause various problems such as congestion, which causes an increase in delay and travel times for traffic heading to and from IH-37 east. According to Texas Department of Transportation (TxDOT), this project is in the initial construction phase. Thus, it is necessary to develop an alternative interchange design that is capable of reducing the problems previously mentioned. This study focused on the issues with frontage roads due to the absence of direct connectors using crash analysis and the results obtained from microscopic simulation tool (VISSIM) to prove the presence of direct connectors will have a significant increase in efficiency of frontage roads at an interchange