Estimation of critical gap based on Raff's definition.

Area of Science:

• Traffic Engineering
• Transportation Science
• Operations Research

Background:

• Critical gap is vital for unsignalized intersection capacity and delay analysis.
• Existing models often simplify traffic flow assumptions.

Purpose of the Study:

• To develop and validate new models for critical gap calculation.
• To improve the accuracy of capacity and delay estimations at unsignalized intersections.

Main Methods:

• Derived two models: M3 definition model and revised Raff's model.
• Utilized Raff's definition of critical gap and total rejected coefficient.
• Employed simulation for model comparison and validation.

Main Results:

• Both M3 definition and revised Raff's models were found to be valid.
• M3 definition model offers simplicity and validity.
• Revised Raff's model provides more extensive applicability and accuracy than the former Raff's model.

Conclusions:

• The M3 definition model is a simple and valid approach.
• The revised Raff's model adheres strictly to Raff's definition, offering broader application and enhanced accuracy.
• Both new models yield consistent results and improve upon existing methods.