Wells + Associates’ traffic design team works with civil engineers, architects, public agencies, and developers, providing a complete range of traffic design services including traffic signal design, modification, and warrant studies; signing and pavement marking plans; lighting plans; and intersection design.
Our traffic design engineers and consultants work in consultation with traffic engineering and planning teams, departments of transportation, county and regional planning offices, and municipalities. With extensive project experience across the United States, we assist with the design of new traffic control devices and the modification of existing installations due to changing traffic patterns and use, with a focus on Complete Street design principles.
Traffic Design Expertise for Civil Engineering Firms, Developers, and Transportation Engineering Teams
W+A’s traffic design consultants provide traffic signal design services for new and existing roadway and intersection projects. Our work on state and local projects is based on the Federal Highway Administration’s Manual on Uniform Traffic Control Devices (MUTCD) which specifies the legal standards by which traffic signs, road surface markings, and signals are designed, installed, and used.
We work closely with civil engineers and developers to create accurate cost estimates for a wide range of traffic design projects.
Our traffic design work includes:
Traffic Signal Warrant Analyses
Do the traffic conditions at a particular intersection or location justify the installation of a traffic signal? Our traffic engineers perform signal warrant analyses to study the traffic conditions, pedestrian characteristics, and physical characteristics to determine whether a signal is warranted. These traffic signal operational evaluations are accomplished using analysis tools such as Synchro/Sim Traffic, Passer, and the Highway Capacity Manual.
The MUTCD specifies nine different types of signal warrants. Depending on the type of warrant required, factors that come into play in signal warrant studies include:
- peak-hour volumes
- the number of vehicles entering the intersection during four-hour and eight-hour periods
- pedestrian volume on crosswalks
- school crossings
- crash experience at the intersection
- the roadway and coordinated signal system
- posted speed limits
Traffic Signal Installation and Traffic Signal Modification Plans
Over nearly three decades, our team has prepared hundreds of traffic signal installation and traffic signal modification, replacement, and improvement plans for civil engineering projects, real estate developments, and county and municipal projects. Our licensed engineers work on a wide range of design and installation plans such as:
- simple intersection signals
- temporary signals for use during construction
- suburban and neighborhood systems
- pedestrian signal crossing plans
- complex urban traffic intersections
This work often involves obtaining traffic counts at proposed signalized intersections on weekday, weekend, and peak travel times so that up-to-date information could be used in the development of timing plans.
Our installation and modification planning experience includes:
- the use and consideration of loop detectors
- turning movements
- signal equipment and pole locations
- signal head and overhead signing decisions
- timing parameters for pedestrians
- turning radii guidelines
- power sources for traffic signals and signal controllers
Our focus routinely involves satisfying DOT design requirements, designing for possible changes in phasing, designing to accommodate future pedestrian trails and sidewalks, and accommodating potential future widening.
Signing and Pavement Marking Plans
The W+A traffic design team creates signing, striping, and pavement marking plans for a wide variety of situations. Signing and pavement markings are important components to create the separation of traffic flows in separate or opposite directions, to mark the edge of roadways, one-way roadways, and travel lanes, and to encourage or discourage crossings, among other uses.
As standardized in the MUTCD, these signs and markings are known as “traffic control devices” and guide the movement of vehicular, transit, bicycle, and pedestrian traffic in every conceivable configuration, including intersections, interchanges, lane reduction transitions, islands, channelizing devices, stop and yield lines, lane use arrows, pedestrian crosswalks, parking spaces, speed measurement and reduction markings, curb markings, and speed hump markings.
Our signing and pavement marking designs are often part of larger traffic signal plans, roadway designs, maintenance of traffic plans, and development projects. Where required, they are signed and sealed by a registered professional engineer on our team.
Maintenance of Traffic Plans
We work with civil engineers and development teams to create plans for the maintenance of traffic, or traffic control plans, when roadways and intersections are undergoing construction, whether due to site development, road construction, utility work, or other cause. Our maintenance of traffic design work helps direct and control traffic through construction sites and detours using appropriate pavement markings, signing, and signals.
We have created maintenance of traffic plans in many different environments, from busy, highly trafficked urban streets to suburban neighborhoods to rural areas, including bridge traffic. This work is guided by MUTCD standards and relevant local guidelines.
Our traffic and lighting design team manages lighting projects for architects, civil engineers, developers, and public jurisdictions such as cities, counties, and municipalities. The W+A lighting design team includes licensed professional engineers, enabling us to help clients obtain site plan approvals in a timely and cost-effective manner.
Our lighting design experience includes:
- Parking lot lighting
- Lighting load design
- Streetscape lighting, roadway lighting, roundabout lighting, and trail lighting
- Lighting for walkways, pathways, and crosswalks
- Intersection lighting, in conjunction with traffic signals
- Upgraded lighting for enhanced lighting installations
- Bollard lighting
Contact our Traffic Design Team
Executive VP | (703) 676-3643
Chris Turnbull leads the W+A traffic design team. He has provided transportation planning and traffic design solutions for private real estate developers and public sector clients for three decades on projects across the United States – from the Washington, DC metro area to the Midwest and West Coast.
William F. Johnson
Vice President | (703) 676-3653
A licensed Professional Engineer, Will Johnson manages a range of traffic engineering projects, including traffic impact studies, bicycle and pedestrian evaluation, and roundabout design. He is a former Adjunct Instructor for Civil, Environmental and Infrastructure Engineering at George Mason University.
Senior Associate | (703) 676-3604
Larry Sefcik has three decades of experience in signal warrant analysis and design, sign and pavement marking, development of traffic control plans, traffic simulation, bicycle and pedestrian studies and design layout, and other operational studies.