Wang, Bo (2013-08). Investigation of the Implementation of Ramp Reversal at a Diamond Interchange. Master's Thesis. Thesis uri icon

abstract

  • Diamond interchange design has been commonly utilized in United States to facilitate traffic exchange between freeway and frontage roads. Another less common interchange design is X-ramp interchange, which is the reversed version of diamond. The major benefit of X-ramp interchange is that it can keep travelers on the freeway until the downstream exit ramp to avoid going through the intersection. It also has drawbacks such as travelers with cross street destinations will experience more delay. This study focuses on when the ramp reversal is desirable. To compare the diamond and X-ramp design, an experimental design is conducted using Latin Hypercube Design method. Four varying factors include interchange design type, traffic volume on the frontage road, through movement percentage and saturation rate of the intersection. 40 scenarios are generated for simulation study using Synchro and VISSIM. Based on the simulation study, optimal signal timing strategies are recommended for each type of interchange design under various traffic conditions. Also, ramp reversal is found closely related to the following factors such as interchange frequency, upstream interchange design, traffic volume on frontage road, through movement percentage and intersection saturation rate. Conclusions are made on when X-ramp is better than diamond interchange design. At last, future research directions are recommended.
  • Diamond interchange design has been commonly utilized in United States to facilitate traffic exchange between freeway and frontage roads. Another less common interchange design is X-ramp interchange, which is the reversed version of diamond. The major benefit of X-ramp interchange is that it can keep travelers on the freeway until the downstream exit ramp to avoid going through the intersection. It also has drawbacks such as travelers with cross street destinations will experience more delay. This study focuses on when the ramp reversal is desirable. To compare the diamond and X-ramp design, an experimental design is conducted using Latin Hypercube Design method. Four varying factors include interchange design type, traffic volume on the frontage road, through movement percentage and saturation rate of the intersection. 40 scenarios are generated for simulation study using Synchro and VISSIM.

    Based on the simulation study, optimal signal timing strategies are recommended for each type of interchange design under various traffic conditions. Also, ramp reversal is found closely related to the following factors such as interchange frequency, upstream interchange design, traffic volume on frontage road, through movement percentage and intersection saturation rate. Conclusions are made on when X-ramp is better than diamond interchange design. At last, future research directions are recommended.

publication date

  • August 2013