> I've seen it argued that shoulders/sidewalks actually make roads more dangerous, because drivers drive faster when they're present. It depends on a lot of fa

> I've seen it argued that shoulders/sidewalks actually make roads more dangerous, because drivers drive faster when they're present. It depends on a lot of factors. The presence of a separated sidewalk might imply a hard separation between vehicular and pedestrian traffic which can increase speeds. Deliberately blurring those boundaries, as is often done in small European cities, makes the road more ambiguous and this leads to slower, more cautious drivers. Confidence equals speed. Long, straight, wide roads with ample room for stopping encourage people to drive faster. Narrow, winding, difficult to navigate roads are naturally approached with more caution. The trend has been to straighten out and widen narrow roads, to eliminate any impediments to "traffic flow", which often makes for roads over-engineered for their intended speeds. The presence of a sidewalk doesn't make people drive faster, but the philosophy of separation of traffic flows that leads to sidewalks being used does.