• BPG Designs

    Optimized Procedures for Slope Inventory in Phoenix, Arizona

    Phoenix, Arizona

Project Summary

Project

According to U.S. Census data, the 65-and-older population is growing approximately 2.5 times faster than the combined population of all age groups. People within this population tend to have trouble moving along sidewalks and crossing roads. To help accommodate this growing number of people, the Americans with Disabilities Act (ADA) instituted the Public Right of Way Accessibilities Guidelines to ensure the mobility-impaired do not face any kind of transportation barriers, including steep slopes. Municipalities like the city of Phoenix, Arizona face potential risk from noncompliance; however, the Phoenix government did not know which roads and sidewalks were too steep. The city partnered with BPG Designs to determine noncompliant roads and sidewalks.

Solution

BPG Designs began by measuring the slopes of area roadways and sidewalks to ensure they comply with ADA guidelines. BPG used a car-mounted LiDAR system to collect images of over 630 miles of roads. These images were combined into a 3D model of the city’s street assets, with high-precision point clouds allowing users to access an array of data at each point in the model. With the assistance of Bentley experts, BPG created scripts that could automatically detect slopes and measure slope grades within the captured images.

Outcome

By combining captured images and automated scripts that could automatically detect and measure slopes in roads, BPG created a slope inventory of Phoenix roads that is free of errors in classification, measurement, or variability. The combined system significantly shortened the time needed to measure road networks and eliminated the need for any on-site remeasurements. The city of Phoenix can now use this information to improve sidewalks and right of ways, ensuring that they can be used by the mobility impaired. BPG plans to use Orbit applications on future projects to ensure consistency and repeatability.

Software

Orbit Content Manager, combined with BPG’s car-mounted LiDAR, gathered and managed all road data gathered for the project. Orbit Feature Extraction allowed the team to manually draw slope lines with the slice view function, identifying the level of noise in point-cloud data. Scripts created within Orbit Feature Extraction allowed the mapping team to fine-tune measurements and calculations to determine the optimal method for automated slope measurement.

Project Playbook:  Orbit Content Manager, Orbit Feature Extraction

Outcome/Facts
  • The Americans with Disabilities Act instituted maximum slope grades for roads and sidewalks to ensure accessibility.
  • BPG Designs used a car-mounted LiDAR system and Orbit Content Manager to capture images of 630 miles of roadways in Phoenix.
  • Within Orbit Feature Extraction, BPG created scripts that could automatically detect and calculate slopes on images.
  • BPG plans to use Orbit for future mapping projects to ensure consistency and repeatability.
Quote:
  • “The time savings, repeatability, and documentation allowed BPG to provide an accurate, quality result for over 630 centerline miles that was delivered on time and exceeded the expectations of the clients.”

    Gentry Nissen GIS Specialist BPG Designs