Traffic Engineering

An impact study (often called Traffic Impact Study or Traffic Impact Analysis, often times abbreviated T.I.S. or T.I.A.) is needed to satisfy State or local Governments Regulations regarding growth management or Adequate Public Facilities Laws.

The peak hour is the highest four (4) consecutive 15-minute periods that typically occur between 6:30 AM & 9:30 AM and 4 PM & 7 PM. It is the heaviest one-hour during the morning and evening commute periods.

A traffic signal can only be obtained from State or local Government if it meets particular volume warrants that are set forth in the MUTCD (Manual on Uniform Traffic Control Devices), a federally mandated publication that provides guidelines on when a traffic signal can be installed. Most traffic signals are installed based upon volume warrants where the traffic volumes are significantly high on the major street such that it creates long delays for vehicles exiting from the minor street. A retail development of 80,000 sq ft to 100,000 sq ft and an office development of 300,000 sq ft will normally meet the minimum thresholds for Government to consider the installation of a traffic signal.

COMAR (Code of Maryland) regulate the State Highway Administration. There is an established process whereby, whenever a property owner or developer desires to have an entrance to a State Highway, an Access Permit must be obtained. The State Highway Administration has the right to deny an entrance permit if access can be gained from an adjoining County or municipal roadway. The State Highway Administration has the right to require an access permit even if the driveway exists, but the property owner wants to change the configuration, size, or development that the existing entrance serves.

Under most circumstances, an access permit can be obtained within a three to six-month time period after the access permit plans have been prepared by the civil and traffic engineer and submitted to the State Highway Administration with appropriate access permit documentation. The State Highway Administration requires a 150% bond to be posted on the construction cost of the access for all work to be undertaken within the State Highway Administration right-of-way.

The benefits of a roundabout versus a traffic signal have become quite evident over recent years. Roundabouts reduce vehicle delay, roundabouts reduce vehicle emission, roundabouts reduce accident frequency and severity.

The diameter of a single lane roundabout ranges from 110 ft to 120 ft.

A common traffic circle does not have the capacity nor the accident reduction capability of a modern roundabout. A traffic circle does not have the geometric design standards that exist with today’s modern roundabouts.

It is recommended by the Federal Highway Administration that the modern roundabout have approach grades of no greater than 3% to 5%.

The Traffic Group, Inc. has gone through years of extensive training, both on a national and an international basis, to understand the “nuances” of designing today’s modern roundabouts. “Tweaking” of poorly designed roundabouts can significantly increase capacity and reduce accident severity by simply making minor changes to the entrance radii.

Maryland Law now states that private property owners in residential communities, commercial communities, and retail communities, must be in conformance with the Manual on Uniform Traffic Control Devices relating to signing and markings. Failure to do so could lead to unnecessary accidents and potential lawsuits.