Sidewalk Study Compares Machine and Manual Measurements

sidewalk vertical

By Neil Nachbar

When it comes to infrastructure maintenance, sidewalks usually take a backseat to roads and bridges. In fairness, not many accidents or fatalities occur because of a crumbling sidewalk. However, those who use sidewalks regularly depend on them being in good condition.

Assessing the condition of sidewalks is a slow, expensive process. URI Mechanical, Industrial and Systems Engineering Professor Jay Wang is researching a way to expedite the process, without sacrificing the accuracy of the calculations.

“Most of the sidewalk measurements and assessments in Rhode Island are done manually, which is cost and time consuming, and its progress is lagging behind the national schedule,” said Wang. “In order to keep up with the national schedule, in compliance with ADA (Americans with Disabilities Act) requirements, and improve the walkability of the sidewalks in Rhode Island, an automated sidewalk quality assessment system is needed.”

Last year, Wang received a total of $150,325 from the Rhode Island Department of Transportation (RIDOT) to study the accuracy and efficiency of using an automated sidewalk quality assessment system.

“The study is intended to identify the functionality and specifications of such a system and to determine whether to custom-build or buy a system to assist the current sidewalk measurement and evaluation process,” explained Wang.

A system made by Surface Systems & Instruments (CS8900), was purchased for the project. Approximately the size of a Segway, the machine is capable of measuring the evenness, grade, cross slope, obstacle identification, and surface texture per ADA guidelines. The device isn’t inexpensive however. The machine itself costs over $40,000. The software, a laptop and training costs an additional $10,000. With a 20 percent education discount provided by the vendor, the total cost is $40,300.

Three Mechanical, Industrial and Systems Engineering students conducted field tests, Ph.D. candidate Sanaz Motamedi, senior Ulices Ortiz and junior Robyn Johnson.

“Robyn and Ulices were involved in collecting sidewalk measurements on the URI campus, using both the manual method and the automated system,” stated Wang. “Ulices is also working on developing an SOP (standard operating procedure) document for the SSI system. Sanaz was mostly responsible for supervising the measurement process and analyzing the data collected.”

The field measurements tested the automated system’s accuracy, quality and reliability of the data collected. Those figures were then compared to measurements collected using the conventional manual method.

Once all the tests are completed, the results could indicate that the automated system was not only accurate and reliable, but took a fraction of the time that the manual method took to collect the data.

As far as RIDOT adopting the automated system in place of the traditional method, there are additional factors to consider.

“The system will be assessed on its compatibility with the current RIDOT GIS database, its completeness of data collected, its cost effectiveness, and its capability to collect measurements on both existing sidewalks and those under construction,” explained Motamedi.

According to Wang, the final report presented to RIDOT will include literature reviews of the automated system, research methodologies, results and analyses, discussion, and specific recommendations. An SOP will also be provided, to guide the implementation of the system in actual use.

Of course, state and local government agencies can’t make decisions regarding infrastructure without knowing the financial ramifications.

“A cost effectiveness study will be provided in the final report,” said Wang. “It will primarily be based on the cost comparisons of manual measurement versus automated measurement, assuming a five-year life span of the machine.”

Motamedi expects the study to be of great use to RIDOT and hopefully in the long run, make a difference to the public.

“Hopefully the study will provide RIDOT with a better and easier process for sidewalk evaluation and assessment,” stated Motamedi. “For those using the sidewalks, the goal is for this research to lead to enhanced sidewalk quality and improved safety and accessibility.”

The segment of the public that could benefit the most from this study is Rhode Island’s disabled population. Based on the 2012 Disability Status Report conducted by Cornell University, the disabled population in Rhode Island is 12.5 percent.

“To these individuals, accessible and safe sidewalks enable them to reach their destinations in the community and enjoy the benefits of city services, programs, and activities,” said Wang. “It is thus important to pay attention to sidewalks and ensure that continuous, handicap-friendly, unobstructed sidewalks are maintained and are in operable working condition.”

Wang also pointed out that there are also environmental and safety benefits to having well maintained sidewalks.

“Sidewalks have become more and more attractive as a low-carbon transportation mode in recent years,” stated Wang. “Presence and quality of sidewalks have also been found to be significant predictors of perceived safety and general satisfaction in the inner city and urban areas.”