). While this approach offers a comprehensive and precise result, the main disadvantage is in the cost and time required to perform this assessment.  Only the wealthiest and biggest city governments are able to afford it, and if they are able to afford, this survey can only be performed once every few years limiting what the city can do with the data.
Another technology that has been proposed is a crowdsourced approach using inexpensive accelerometers called Street Bump. Street Bump was developed in the Boston Mayor's Office of New Urban Mechanics. A limitation with this approach is that is designed for car owners,  potentially biasing results. Another limitation of using Street Bump  to survey city streets is the absence of street imagery.  Without imagery to back up the data, Boston has no way of knowing the "ground truth" of street quality. The Street bump dataset appears to be contain only accelerometer readings that profile a small section of the road and can suffer from calibration issues.
The SQUID approach extends Street Bump as it operationalizes the common adage, "A picture is worth 1,000 words", and if pictures of the entire width of a street segment were captured, street quality for the entire width of the street can be measured in manner that is holistic and empirical.