A chain is no stronger than its weakest link. This fundamental concept can also be applied to roads in the sense that a road is only as effective at moving traffic as its widest (and most efficient) point. There are many examples in Ottawa and around the world of important roads that, while considerably wide along much of their length, fatally narrow at certain points. These narrow points mean less traffic can flow through, impacting the effectiveness and capacity along the entire length for the road.
Vancouver, with its lack of highways, is one of only a few cities which rely exclusively on surface streets. This fundamental difference makes analysing the effectiveness of some of their transportation infrastructure choices very interesting.
The heavy reliance on a grid roads to move traffic around makes the effectiveness of intersections extremely important. There are three types of intersections used in Vancouver which warrant discussion: four-way signal-controlled intersections, two-way signal-controlled intersections, and pedestrian crossings.