Our Team

Meet the D.S. Thaler & Assoc., LLC Team

David S. Thaler, PE, LS, DFE, D.WRE, FRGS, F.ASCE, F.NSPE
Principal and Managing Member

Brian L. Childress
President

Brian has spent his entire career in the engineering field, specifically doing land development engineering in Central Maryland. He has risen to the presidency of D.S. Thaler & Assoc., LLC. His responsibilities include overall supervision of the technical aspects of the firm. He has worked on innumerable projects in Baltimore, Anne Arundel, Howard and Frederick counties as well as in southern Pennsylvania.


He has extensive experience in all aspects of Baltimore County land development processing, having worked on several hundred projects. He has testified and been accepted as an expert before the Administrative Law Judge.

Stacey A. McArthur, RLA
Chief, Department of Landscape Architecture

As Director of our Planning Department, Stacey utilizes the design process to incorporate the client’s vision in conjunction with the multitude of regulatory requirements to achieve a viable development project.


Stacey has extensive land development experience ranging from initial feasibility studies through to final closeout certification. This includes the creation of site design, Planned Unit Developments (PUD) in addition to using accompanying supporting documentation ranging from the development of graphic design guidelines to landscape plans.


Stacey is proficient in the implementation of various environmental factors including forest conservation, forest buffers, variances, alternatives analysis, special variances, Chesapeake Bay Critical Area development including Growth Allocation Requests and Variation of Standards.


Additionally, Stacey is well versed in the preparation of various zoning matters ranging from variances to non-conforming uses. She is also qualified and has extensive experience testifying on behalf of our clients before the Administrative Law Judge, and the Baltimore County Board of Appeals.

Mark S. Vaszil
Vice President Engineering

John Motsco, P.E.
Senior Project Manager and Principal II

A graduate of the Pennsylvania State University and Maryland licensed professional engineer, John has experience in land planning, zoning, stormwater management, construction management and engineering design. John has worked on hundreds of projects throughout the Baltimore metropolitan area.
John enjoys an extraordinary reputation for facilitating the development of projects with challenging engineering, zoning and environmental issues. He has developed considerable experience in providing expert testimony on highly contested cases at both before the Administrative Law Judge and the Baltimore County Board of Appeals. John has extensive experience related to historic preservation, religious uses, floodplain regulations and complex engineering issues.

A graduate of the Pennsylvania State University and Maryland licensed professional engineer, John has experience in land planning, zoning, stormwater management, construction management and engineering design. John has worked on hundreds of projects throughout the Baltimore metropolitan area.


John enjoys an extraordinary reputation for facilitating the development of projects with challenging engineering, zoning and environmental issues. He has developed considerable experience in providing expert testimony on highly contested cases at both before the Administrative Law Judge and the Baltimore County Board of Appeals. John has extensive experience related to historic preservation, religious uses, floodplain regulations and complex engineering issues.

Edward S. Keohane, P.E.
Senior Project Manager and Principal II

A graduate of the University of Central Florida, Edward is a registered Professional Engineer in Maryland, Florida, New Hampshire and Delaware. He has experience in all aspects of civil engineering with emphasis on water resources and roadway design. He has managed and designed a wide array of projects ranging from residential subdivisions to major retail/office complex projects. Transportation experience includes state and county roadway design.


Several projects that he has designed have been acknowledged for creativity in planning and engineering. These are National Harbor, Maryland, the development of the Orlando Naval Training Center, known as Baldwin Park in Orlando, Florida as well as Florida’s first tri-signature (Fazio/Palmer/Dye) golf course and subdivision at Lake Nona, Florida.


Edward has comprehensive experience and has engineered projects across Baltimore County, Prince George’s County, Anne Arundel County, Montgomery County, and St. Mary’s County, Maryland.

David B. Copeland, Prof. L.S.
Chief of Surveys

The D.S. Thaler Leadership Team