When crossing or entering traffic on a highway, what space is needed?

• A. Half a block on city streets.
• B. A full block on the highway.
• C. One mile.
• D. Ten feet.

Answer: (B)

Entering highway traffic requires a large, clear gap because you’ll be accelerating to highway speeds and must merge into fast-moving traffic. Having a full block of open highway ahead gives you enough distance to accelerate smoothly, match the flow, and slip into traffic without forcing others to slow or swerve. A half block works for city streets where speeds are lower, but it doesn’t provide enough room on a highway. Ten feet is far too short to merge safely at highway speeds, and a mile is more than needed for safety and isn’t the standard measure used in this context. If conditions are heavy or speeds are high, you’d still look for as much space as possible, but the general rule is to have a full block of space on the highway before crossing or entering.