Design and Geospatial Services

PennDOT, District 8-0 retained Erdman Anthony to design the widening of 2.6 miles of existing Interstate 83, improving capacity between its junction with Interstate 81 (Exit 70) and the Mountain Road interchange (Exit 72) in Lower Paxton Township, Dauphin County.

Erdman Anthony’s design has relieved traffic congestion, improved infrastructure conditions, and introduced safety improvements. The project’s features included:

• An auxiliary lane added in both directions to connect the ramps at the two interchanges, relieving congestion during morning and evening rush hours
• Concrete roadway slab repair, joint repair, and an overlay of the entire project area
• Pavement repairs specified by the PennDOT maintenance unit
• Drainage improvements
• Signage updates
• New pavement markings
• Additional storm water management facilities Our approach to storm water management made optimal use of existing right-of-way by rehabilitating existing facilities wherever possible and using linear vegetated swales and infiltration trenches as best management practices (BMPs).

Traffic control and construction staging were key design issues, with approximately 84,000 vehicles per day using I-81 through the project area. Existing conditions severely constrained the proposed design, and the widening had to occur without taking additional right-of-way or replacing existing bridges.

These circumstances made accurate mapping essential. Our geospatial team provided in-house surveying support by using mobile LIDAR to gather geospatial data during the site’s high-traffic volume conditions. Relying on mobile LIDAR within the travel lanes provided:

• Complete and accurate coverage of the roadway, signage, and bridges
• Significant reduction of survey crews’ exposure time to moving traffic
• Protection for survey crews while allowing full traffic flow by using attenuator trucks during required targeting along the shoulders

Outside the roadway, Erdman Anthony used Real Time Kinematic GPS and more conventional survey techniques to map existing drainage, noise walls, and other features.

Erdman Anthony’s geospatial team also:

• Performed the surveys in accordance with PennDOT’s DM3 and Publication 122M
• Provided deliverables in requested MicroStation and InRoads formats

Because this project is part of a larger interstate improvement initiative, final design was completed under an expeditious schedule, with construction plans, specifications, and estimates delivered just seven months after Erdman Anthony received design field view approval from PennDOT.