Should the Diverging Diamond Interchange Always be Considered a Diamond Interchange Form?

Abstract

The diverging diamond interchange (DDI) has proved to be an ideal interchange solution because of its safety features, low costs, and operational benefits in different scenarios of turning movement volume. Pre vious studies have compared the DDI with other interchange forms by using the same number of through lanes for each interchange design. Those studies used microsimulation software for the analysis and had a limited number of turning movement combinations to sample. This study considered a large sample of turning movement combinations and compared more interchange configurations to determine whether the DDI might have more applications than previous studies have indicated. A basic form of the critical lane volume method was used to evaluate the different interchange configurations. Although this method is not the most perfect method, there is reason to believe that the results are accurate enough to indicate that the DDI may be a viable option in many more scenarios than previously thought. This study concludes that it is worthwhile for practitioners to consider the DDI for any interchange improvement when comparing it with other diamond interchange forms.