ROBOTICS FOR SIDEWALK ASSESSMENT & INVENTORY:
Leveraging Technology for ADA Compliance (2024)
Overview
Many cities struggle to keep their sidewalks accessible and safe for pedestrians, putting them at risk for ADA-led litigations and lawsuits.1 Cities spend up to $7 million annually on ADA lawsuits, creating an urgent need for cost and time-efficient ways to undertake sidewalk assessment and repair.2, 3 Poor conditions of city sidewalks are partially caused by the time and resource limitations of traditional surveying methods. Municipalities complete sidewalk assessments instead, but these tend to generate limited data. (figure 1)
Current Methods
Commonly used sidewalk assessment methods are challenging for cities that need well-developed plans to assess their broad sidewalk conditions. Often using manual equipment to measure and record the intricacies of sidewalk terrain, these methods are laden with inherent difficulties that impede efficiency and accuracy.4 The significant time and human resources that can be required result in further strain on the limited resources of the city’s public works, leaving little room for broad sidewalk condition assessments to occur in a timely fashion5
ADA Assessment Comparison*
Current methods must often choose between sacrificing information or speed. As an example, we looked at the evaluation criteria from three city sidewalk assessments, which these three jurisdictions completed:
- San Diego, CA, boasts 5,000 miles of sidewalks and completed its assessment using engineering interns who recorded data on hand-held GPS devices.
- Austin, TX, utilized its public works department to record more detailed measurements and has been assessing its sidewalks since 2016. However, it has only covered 17% of its 2,700 miles of sidewalks.
- Pekin, IL, is a small town of 31,00 people with just a few hundred miles of sidewalks. It utilized an engineering company that employed mobile LiDAR.
USING ROBOTICS
By quickly gathering data, robotics reduce time spent in ADA sidewalk surveillance. However poor ground-level GPS accuracy caused by interference from proximity to buildings and difficulty obtaining accurate vertical measurements from the air have plagued development in this field.
Dax robots solve this by utilizing their track design and RTK GPS, which gives them a precise understanding of their location. They then use LiDAR to measure defects in the sidewalk. Like a drone, Dax know their position with a 2cm accuracy, and like a ground-mounted LiDAR device, they can also accurately gather vertical measurements. Data collected by Dax is uploaded to ArcGIS, along with a color-coded risk assessment map overlay, which considers defects present and the average amount of foot traffic that any given sidewalk segment sees.
Methodology
Dax records detailed terrain data by breaking sidewalks into segments. It inspects and measures each segment for running slope, cross slope, uplift, cracking fixed obstructions, and other ADA violations. It also photographs each segment.
This information is then gathered and uploaded onto ArcGIS for city engineers to evaluate and determine areas of priority. Information is made more readily digestible by assigning each section of the sidewalk a risk assessment number, which is taken from the sum of defects in a segment and multiplied by the amount of traffic that the segment experiences. This algorithm produces a color-coded risk assessment map, which cities can use to inform their repair assessment process.
Gathering Data- Dax perspective
Dax drives at a speed of 228.5 Meters/Hr while gathering technical data. He is also a semi-autonomous robot working with remote operation, so data is collected without coordinating hardware and large groups of personnel. This speed and simplicity drastically reduce the costs of gathering data on the current condition of city sidewalks.
Estimate cost for sidewalk survey from Oregon, USA surveyor.
CONCLUSION
Accurate, quickly gathered graphical data on the current condition of city sidewalks allows cities to move forward. It also enables cities to enforce the upkeep of pedestrian paths. With accurate data on the state of its sidewalks, a city can
- Evaluate the need for repairs
- Make data-informed recommendations for additional funding to keep sidewalks safe
- Respond to lawsuits
- Inform litigation efforts
- Take advantage of funding opportunities
Robotics provide new tools for simplifying manual data-gathering processes. We can use the next wave of robotic technology to make pedestrians safe and city sidewalks accessible. Dax does this in a cost and time-effective manner, bringing much needed data to public officials tasked with overseeing the billions of dollars worth of sidewalks in their cities. Better sidewalks start with good data. Data that is now more accessible than ever.
Citations:
- 2010 ADA Standards for Accessible Design – Ada.Gov, archive.ada.gov/regs2010/2010ADAStandards/2010ADAStandards_prt.pdf. Accessed 21 Dec. 2023.
- “Repairing L.A.’s Broken Sidewalk Strategy.” Office of Kenneth Mejia, LA City Controller, controller.lacity.gov/audits/sidewalks. Accessed 20 Dec. 2023.
- Solomon, Adina. “Ada Lawsuits Target Poorly Maintained Sidewalks.” Bloomberg.Com, Bloomberg, 16 Aug. 2018, http://www.bloomberg.com/news/articles/2018-08-16/ada-lawsuits-target-poorly-maintained-sidewalks.
- ‘Managing Selected Transportation Assets: Signals, Lighting, Signs, Pavement Markings, Culverts, and Sidewalks’ at Nap.Edu.” Chapter Seven – Sidewalks | Managing Selected Transportation Assets: Signals, Lighting, Signs, Pavement Markings, Culverts, and Sidewalks | The National Academies Press, nap.nationalacademies.org/read/23132/chapter/9. Accessed 20 Dec. 2023.
- Jane Gibson, P., & Marshall, W. E. (2022). Disparate Approaches to Maintaining Roads and Sidewalks: An Interview Study of 16 U.S. Cities. Transportation Research Record, 2676(9), 553-567. https://doi.org/10.1177/03611981221087239