This post works through two examples to make a case for measuring density in terms of population per length of street rather than population per unit area.
It uses two different building typologies to distribute people. While these are typologies rather than measures of density, they are important because they are often how higher level, block-based densities get interpreted and applied at the scale of the urban block.
In both cases a consistent block size and population have been used. The variation comes from the way this population is distributed at the block level (through individual buildings on individual plots, or through a single building on a single plot.
These two approaches have then been distributed across a grid of streets, and compared in terms of the number of people who live on each street. While this is a very simple measure – it does not consider the people who may be passing through the street as part of a larger scale journey – it does give an impression of the latent activity that could occur.