Sub-problem 3b: Ramps

The HCM’s ramps chapter focuses on three aspects of ramp analysis: merge points, diverge points, and the intervening roadway. Below are examples of the methodologies needed based on the characteristics of the ramp area.

If a ramp starts with a diverge that isn’t at the end of a weaving section (e.g., a freeway exit ramp), passes through a middle section, and ends with a merge (e.g., a freeway on-ramp), you need the methodologies in the ramps chapter.

However, if you have a signalized or unsignalized intersection at one end or the other, or if one of the two ends is part of a weaving section, then you will use the methodologies in weaving section chapters.

If the ramp starts as the outbound leg of a signalized or unsignalized intersection (e.g., a roundabout), then you need to use the signalized or unsignalized analysis procedure.

If the ramp ends as a merge (e.g., an entrance ramp, either onto a freeway or a surface arterial) and it’s not the start of a weaving section, then you need to use the ramps methodology.

If it is the start of a weaving section, you need to use the weaving methodology.

If it’s an approach to a signalized or unsignalized intersection, you need to use the signalized or unsignalized analysis procedures as appropriate.