Bottleneck and Roadblock

Bottleneck noun - A crowded mass (as of cars) that impedes or blocks movement.

Roadblock and bottleneck are semantically related. In some cases you can use "Roadblock" instead a noun "Bottleneck".

Roadblock noun - Any condition that makes it difficult to make progress or to achieve an objective.

Bottleneck and roadblock are semantically related. Sometimes you can use "Bottleneck" instead a noun "Roadblock".