as automobile use increased amongst the middle and upper classes. By the 1930s, the once-profitable streetcar companies were diversifying by adding motorized buses and trackless trolleys to their fleets. By the 1940s, streetcar ridership had dropped dramatically, and few subdivisions were being built with streetcars or mass transit in general in mind. By the 1950s, nearly all streetcar lines had stopped running, and were instead served by buses. Modern streetcar suburbs Now somewhat urban in appearance, former streetcar suburbs are readily recognizable by the neighborhood structure along and near the route. Every few blocks, or along the entire route in well-preserved neighborhoods, there are small commercial structures, storefronts usually flush with the sidewalk; these were small stores—often groceries—operated by "mom and pop" operators who lived in quarters behind or above the establishment. Off-street parking, if it exists at all, is in the rear of the building. Because stores were originally built along streetcar lines, a person could exit the transport near home, do some light shopping for dinner items, and continue by walking to his or her residence. These buildings also provided shopping for a non-employed spouse. Very few small groceries remain (outside of dense cities), though the space is often now used for non-foodstuff retail, capable of drawing clients from outside of the immediate neighborhood. Modern streetcar suburbs are usually served by buses which run roughly the original streetcar routes, and may offer highly reasonable mass transit commute times to downtowns and other business areas, especially compared to later automobile suburbs. Toronto, Ontario, Canada is an example of a city in which most streetcar suburbs are still served by streetcars. House prices in streetcar suburbs vary by neighborhood and city. Lots left empty in these areas during initial development, or where the initial houses have burned or been torn down, are usually too narrow for modern residential zoning regulations, meaning that it is difficult to infill housing in well-preserved streetcar suburbs. Occasionally two lots are combined into one for a wide enough lot, or many houses are torn down for a new use as needed. However, in some cases where historic zoning applies, infill housing is encouraged or required to match neighboring housing standards. Features In a greater sense, the streetcar suburbs of the early 20th century worked well for a variety of reasons. While most cities grew in a piecemeal fashion, without any real plan for future development,