Roadway construction brings with it a host of complexities such as work zone safety, delays, stress, etc. A lot of time and money has been invested in researching ways to improve safety and efficiency of a work zone. The National Highway Traffic Safety Administration (NHTSA) records show that we had 1,026 work zone fatalities across the nation in 2000. Ever since, our Temporary Traffic Control (TTC) planning has improved and contributed in the decrease in number of fatalities with 2013 showing a great improvement with 579 fatalities. Our efforts should not end until we are able to maintain a record of zero work zone related fatalities over a sustained period of time.
What is a work zone/ TTC zone? Construction activity negatively affects the normal function of a roadway unless a temporary traffic control plan is installed in place. Surprisingly there is no nationally recognized definition for a work zone, but every state has its own definition. A work zone can be defined as an area upstream and downstream of the construction activity, where the effects of the construction have an influence on the safety and operations of the roadway users and workers. A smooth transition from upstream to the end of the work zone can be achieved by implementing a temporary traffic control plan using a series of planned and sequenced traffic control devices such as signs, channelizing devices, pavement markings, etc. A TTC plan should be prepared anytime there is a change in normal operations due to a planned activity.
Why do we need temporary traffic control? Maintaining the continuity of function of the roadway when normal operations are suspended during a construction activity is important from a safety and efficiency perspective. A TTC plan helps maintain roadway functions, and, when designed properly, enhances safety and efficiency. A TTC Plan ensures that connectivity of all roadway users is taken into consideration. TTC planning potentially saves financial losses that can occur with vehicular crashes and delays.
Who are the stakeholders when it comes to a TTC plan? Some of the common key stakeholders on a typical construction project are shown in the diagram:
What kind of factors are taken into consideration when preparing a construction signage plan? It is important to remember that every project is unique and each project will need a customized TTC plan. Having said that, some of the common factors described below have to be considered for most projects:
Project Length & Complexity–The area of influence of the construction activity determines the length of the traffic control zone. The type of activity also determines the type of TTC plan that will be implemented. For example, a TTC plan for a one hour utility work will defer greatly from a roadway widening construction project.
Type of Users–Different facility users such as pedestrians, bicyclists, vehicles, transit buses, trucks, and emergency responders have different requirements. A change in normal operations requires planning temporary arrangements for each of these users.
Schedule/ Duration–Construction duration usually falls under one of the following five categories: Long Term Stationary (occupies location for more than three days), Intermediate-term stationary (work occupies location between one and three days), Short-term stationary (work occupies location for more than one hour), short (work occupies location for up to an hour), and Mobile (work moves intermittently or continuously). Based on the category, the TTC plan changes dramatically along with the devices used to implement the plan.
Special Events–A planned special event usually alters traffic patterns locally or regionally, thereby making it necessary to foresee the pattern changes and prepare and implement TTC plans.
Roadway Characteristics–There are several roadway characteristics such as lane widths, posted speed limit, number of intersections, turn lanes, sidewalks, crosswalks, pavement markings, signage, etc. that are taken into account when putting a TTC plan together. For example, speed limit and stopping sight distances can greatly affect the placement distance, size, and type of signs.
Transit/Emergency Operations–Transit routes are pre-set and will require special consideration. A small change in operations could result in a large coordination effort with transit authorities to disseminate information regarding the change in routes and/or timings to the users. Similarly, emergency responders getting timely access to the location of the emergency without being delayed due to the change in normal operations is not acceptable. Hence, having a definite emergency response plan incorporated into the TTC plan is vital.
Other than signs, what types of devices are used in a temporary traffic control zone? Signs play a huge role in guiding roadway users through concise, accurate, and standardized messages. But there are several other devices that are used in a work zone depending on the purpose they are expected to serve. Some of these include channelizing devices such as cones, barrels, etc., and when used in conjunction with pavement markings help guide traffic through the work zone. In addition to signs, certain situations warrant portable, temporary variable message signs to deliver messages. Flaggers play a role in traffic operations in a work zone by using flags and hand gestures to control traffic.
Are there any pre-set plans or does each plan have to be customized for each project? Manual on Uniform Traffic Control Devices (MUTCD) has several illustrations depicting the use of TTC plans for several commonly occurring applications. If the work zone conditions match the project conditions, then the MUTCD pre-set plans come in handy. For unique situations, though, a customized plan is necessary.
For what type of conditions should a TTC plan be prepared? The design should always be prepared for the worst case scenario when some of the following factors are present:
Absent or limited lighting
Bad weather conditions
Limited sight distance
Users with disabilities
New users without prior information regarding the project
What are some of the safety considerations for workers in a TTC zone? Are there any special types of training courses? The MUTCD prescribes special training for workers regarding techniques, devise usage, and placement. It also prescribes using temporary traffic barriers that shield workers from traffic by providing lateral clearances. Speed reduction in the TTC zone is highly recommended. The MUTCD states that a trained professional should determine the requirement for a TTDC plan and ensure that the engineering, administrative, or personal protection measures are planned in accordance with the Occupational Safety and Health Act (OSHA) of 1970.
Are there any special types of training courses available specifically geared towards TTC Planning? Through the Work Zone Safety Grant Program, American Traffic Safety Services Association (ATSSA) was awarded a four-year grant from the Federal Highway Administration (FHWA) to provide roadway safety training nationwide for workers and others who make their livelihood on America’s roadways.
The ATSSA provides training for the following courses:
Traffic Control Technician
Incident Traffic Control for Responders
Traffic Control Supervisor
Florida Intermediate Training
Flagger Instructor Training
Florida Advanced Training or Refresher
State Specific Training
Traffic Control Design Specialist
Pavement Marking Technician
Urban Work Zone Design
Guardrail Installation Training
Night-time Traffic Control
Maintenance and Short Duration Activities
ATSSA Online Flagger Certification Training Course
They also provide the following certifications:
Flagger Certified Pedestrian Safety Professional (CPSP)
Flagger Instructor Training (FIT)
Pavement Marking Technician (PMT)
Traffic Control Technician (TCT)
Guardrail Installer (GI)
Traffic Control Supervisor (TCS)
Truck-Mounted Attenuator Operator (TMA)
Traffic Control Design Specialist (TCDS)
About Foresite Group
Foresite Group is a multidisciplinary engineering, planning, and consulting firm providing services to public and private sector clients nationwide. Our team’s collaborative process results in creative products and services that help our clients achieve their goals. Our team takes pride in enhancing and developing the cities and communities where we live, work, and raise our families.