The imperative to transform car-dependent cities for a low-carbon future requires that we engage with the challenge of increasing densities along existing road-based transit corridors – within the constraints of existing morphologies. Such corridors are often lined with small lots that are valued for their functional mix and urban character. This paper explores the degree to which small and narrow lots constrain urban intensifcation through a study of tram corridors in Melbourne. We examine the impact of site area, shape and access conditions as constraints on re-development and increased density. We fnd that small and narrow lots have not prevented intensifcation that is substantial in its accumulated effect and contributes more to urban character than large lot re-development. The paper discusses the relations of urban morphology to questions of car-dependency, development capacity and resident resistance