Highway geometry: Two circular curves deflecting in the same direction but separated by a short intervening tangent are technically termed as what type of curves?

Introduction / Context:Correct curve terminology is critical for safe and economical alignment design. Different curve combinations (simple, compound, reverse, broken-back) have distinct operational and comfort implications for drivers, especially at speed.

Given Data / Assumptions:

• Two circular arcs in the same turning direction.
• A short tangent lies between them.
• No transition curve has been specified.

Concept / Approach:A compound curve is formed by two (or more) circular arcs of different radii meeting tangentially at a common point with no intervening tangent length. A broken-back curve, by contrast, consists of two circular arcs in the same direction separated by a short tangent between them—an undesirable layout because it introduces awkward steering and sight issues.

Step-by-Step Solution:Identify the presence of a short tangent between same-direction arcs.Recognize that this configuration is the definition of a broken-back curve.Select the corresponding terminology.

Verification / Alternative check:Standard highway texts caution against broken-back curves and recommend replacing the short tangent with a transition or designing a proper compound curve where feasible.

Why Other Options Are Wrong:

• Compound curves: no short tangent between arcs.
• Transition curves: used to connect tangent to circular curve with varying curvature.
• Simple circular curves: single constant-radius arc only.
• None: not applicable since the term exists.

Common Pitfalls:

• Mislabeling compound curves as broken-back when there is no intervening tangent.
• Using short tangents that degrade driver comfort and safety.

Final Answer:Broken-back curves