What is the typical design speed for urban freeways?

What is the typical design speed for urban freeways?

• A. 30–45 mph
• B. 70–85 mph
• C. 45–60 mph
• D. 50–65 mph

Answer: (D)

Design speed for urban freeways is the speed used to shape the roadway’s geometry—curves, sight distance, and the level of curvature and superelevation—that keeps traffic moving safely in an city environment. In urban settings, the goal is to provide efficient flow while fitting into dense interchanges and ramp spacings, so the geometry is planned around a speed near 60 mph. The range that reflects this practice is 50–65 mph, which accommodates a typical target around 60 mph and allows for regional variations. Faster ranges like 70–85 mph would demand gentler curves and longer sight distances than urban interchanges usually provide. Slower ranges such as 30–45 mph don’t align with freeway expectations, where higher speeds are anticipated between ramps. Therefore, 50–65 mph best matches common design practice for urban freeways.

Design speed for urban freeways is the speed used to shape the roadway’s geometry—curves, sight distance, and the level of curvature and superelevation—that keeps traffic moving safely in an city environment. In urban settings, the goal is to provide efficient flow while fitting into dense interchanges and ramp spacings, so the geometry is planned around a speed near 60 mph. The range that reflects this practice is 50–65 mph, which accommodates a typical target around 60 mph and allows for regional variations.

Faster ranges like 70–85 mph would demand gentler curves and longer sight distances than urban interchanges usually provide. Slower ranges such as 30–45 mph don’t align with freeway expectations, where higher speeds are anticipated between ramps. Therefore, 50–65 mph best matches common design practice for urban freeways.