This briefing note introduces the road diet, an engineering technique that reallocates space on a street or road for other uses when they are over-built and have excess lanes. In what follows, we will present a definition, some study results and practical implementation considerations for road diets.
When applied with consideration for contextual details, it is generally agreed that road diets provide significant safety benefits for motorists, cyclists and pedestrians alike.
With fewer and narrower lanes, the crossing distances for pedestrians are shorter, vehicle speeds come down to more appropriate levels, and protected space for cyclists is created. Road diets are most successful on streets carrying average annual daily traffic (AADT) of up to 12,000, but can be implemented on streets with higher volumes if intersections are studied and configured carefully.
Because much of the opposition to road diets stems from misconceptions about the function of the ro…