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Abstract
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BACKGROUND: Urban streets provide three main functions (i.e., transit, access, and place) to meet the needs of urban residents.
Since they comprise about 80% of public spaces in many cities, it is crucial to maintain streets in such a way as to make the most of such a large space. Developing a comprehensive framework of indicators and tools to evaluate the streets' functions makes it possible to achieve this goal. However, most of the developed frameworks cannot reflect the actual use of streets because they rely mainly on measuring physical features (potential use) of streets. This paper proposes a holistic and objective framework to characterize the functions of streets based on their actual use at the microscopic (individual) level.
Methods: A framework has been developed based on two primitive spatial units (i.e., screen line and zone) and three types of events (i.e., crossing, entering/exiting, and dwelling) to observe street users directly for assessing street functions.
The proposed framework is applied in four residential streets in Montreal, Canada, to evaluate the effect of speed bump installation on street functions. The indicators are evaluated by analyzing about 80 hours of video data collected before and after the intervention (October 2019 and 2020) at the four sites. Open-source computer vision tools were employed to detect and track the street users semi-automatically.
Results: The numerical results in the sites show streets experienced different changes in their functions between 2019 and 2020. The following table shows the changes in the number of street users, activities and speed of vehicles. The significant increase in activities (place function) could be attributed to the COVID pandemic. However, the drop in car speed could be related to the speed bump installation.
Conclusions: The results of these sites show how street use changes over time and possible tradeoffs between uses, e.g., transit and place, even if it is difficult to attribute the changes to the possible factors. The direct user observation revealed different changes such as changes in vehicular flow and speed (as traditional transit indicators), but also increases in activities. Such information will help transportation agencies and urban planners to manage streets/public spaces so that they fulfill their expected functions while minimizing the negative impacts.
Language: en |