At the City Council meeting last week, City Engineer Chris Tolnar presented the results of the traffic signal studies that were recently completed for the intersections of SR 59 @ Admore Drive (future extension) and Riverbend @ SR 43. Admore Drive met the criteria to warrant a new signal, Riverbend did not. Read more about the studies, the findings and traffic signals in general.
Here’s the memo from Chris that summarizes the report and the findings:
TO: David Ruller, City Manager
VIA: Eugene Roberts, P.E., Director of Public Service
FROM: Chris Tolnar, P.E., City Engineer
RE: Signal Warrant Studies Admore Drive & SR 59 (West Main Street)
River Bend Boulevard & SR 43 (North Mantua Street)
During the course of the Citywide Traffic Study the above two intersections were identified as areas where consideration should be given to signal warrant analysis due to their location on the identified AMATS Corridors within the City. The Division of Engineering requested that the consultant (Mannik & Smith Group) conduct a warrant analysis for each intersection.
As summary of the new OMUTCD manual and the signal warranting process, requirements and warrants follow.
The Ohio Revised Code (Section 4511.09) requires ODOT to adopt a manual for a uniform system of traffic control devices that conforms to the system approved by the Federal Highway Administration (FHWA). To this end, ODOT publishes the Ohio Manual of Uniform Traffic Control Devices (OMUTCD), which establishes standards for design and use of traffic control devices that conform to the national Manual on Uniform Traffic Control Devices (MUTCD) (published by the Federal Highway Administration (FHWA).
Section 4511.11 of the Ohio Revised Code requires that all local authorities in their respective jurisdictions place and maintain traffic control devices in conformance with the OMUTCD.
The manual further states an investigation of the need for a traffic control signal shall include an analysis of the applicable factors contained in the following traffic signal warrants as well as other factors related to existing operation and safety at the study location.
The warrants are:
Warrant 1, Eight-Hour Vehicular Volume
Warrant 2, Four-Hour Vehicular Volume
Warrant 3, Peak Hour
Warrant 4, Pedestrian Volume
Warrant 5, School Crossing
Warrant 6, Coordinated Signal System
Warrant 7, Crash Experience
Warrant 8, Roadway Network
During the collection of data in a warrant analysis the engineer will collect traffic data (peak hour counts, hose counts) as well as evaluate record information (crash statistics, future growth) as well as specific site conditions that may warrant consideration in the warrant analysis. Typically, the report will not address each of the warrants but will offer the best warrant options and description of how these apply or do not meet the criteria.
Admore Drive & SR 59 (West Main Street)
Warrant analyses were conducted for Warrant 1 – Eight-Hour Vehicular Volume and Warrant 3 – Peak Hour Warrant. These were utilized as they were determined to be the most likely applications as satisfaction of only a single warrant is required for a positive recommendation.
The study determined that with the future conditions, (City of Kent Parks & Recreation soccer fields and skate park facility) and full build out of the adjacent development that a signal would be warranted based on Warrant 1, Condition B and Warrant 3.
The reconstruction of Admore Drive was identified in the current 5 year Capital Improvement Plan. The addition of a signal is anticipated to be approximately $100,000. The project has been submitted for grant consideration from the Issue 2 program. At this time staff has started preliminary design of the project and anticipates being able to bid the project in 2007.
River Bend Boulevard & SR 43 (North Mantua Street)
Analyses were conducted for Warrant 1 – Eight-Hour Vehicular Volume and Warrant 3 – Peak Hour Warrant. These warrants were utilized because they were determined to be the most likely applications since only a single warrant is required for a positive recommendation.
The study determined that with the future conditions and full build out of the adjacent development that a signal would not be warranted based on Warrant 1 or Warrant 3. The study did note that the capacity analysis for the intersection results in a Level of Service (LOS) of F for the westbound River Bend Boulevard movement. However, based on full build out there is not sufficient trip generation available, nor were sufficient vehicles counted to warrant the signal on a volume basis.
In prior studies, there was discussion of warranting the signal based on Warrant 5 – School Crossing. This warrant has two components that need to be met to warrant a signal. The first is the number of gaps in the traffic stream during the period when the children are using the crossing is less than the number of minutes in the crossing period. The second is there are a minimum of 20 students who use the crossing during the period. Based on discussion with Kent City Schools there are 15 students in the middle school and 24 students in the high school who live in the River Bend Development. The school does not bus any of the high school students and only transports those students living in the back portion of the development that is over the 1.25-mile boundary. The Division has conducted informal counts in the AM and PM hours and found that a limited number of students appear to walk from the study area.
At this time it would appear that a signal is not warranted based on the available information collected to date. The Division of Engineering would like direction regarding what should be done by staff regarding this matter. It is possible that in conjunction with a speed study of the area that one of the volume warrants may apply based on a reduction in required vehicles per hour needed if the 85th-perecentile speed is found to be above 40 mph. However, the current study was conducted as a part of the Citywide Traffic Study any additional work will need to be authorized to continue study and further warrant analysis of the intersection. Further study of this intersection will require a modification to the current contract with the consultant and/or the expenditure of additional funds. In addition, should a signal be justified in this intersection it is currently not identified in the current 5 year Capital Improvement Plan.
Before ruling out a signal at Riverbend, Chris recommended additional study of the vehicle speeds at the intersection and Council supported his recommendation.
The first Traffic Signal in the Nation?
1914 In Cleveland Ohio
More on Traffic Signals
Traffic signals have been used for decades to control traffic flow. This has provided engineers opportunities to study their positive and negative impacts, to identify when signals should be installed and to determine how they should be operated. National and state standards have been developed in order to provide uniformity and maximum benefit to the public.
When used under the right conditions, traffic signals may improve traffic flow and safety. In considering when and where traffic signals should be installed, engineers gather information on traffic flows. This may include the amount of vehicle traffic for each fifteen minute period of the day, the direction of traffic, turning vehicles and pedestrians and bicyclists (especially near schools). Traffic speeds and the development in the area are also considered along with the number of travel lanes available at the location.
Traffic flow information assists in determining the potential impacts of a traffic signal on travel delays and how many vehicles can be served by the intersection (capacity). All signals have the potential to increase delays or decrease capacity to some traffic movement and decrease delays or increase capacity to other traffic movements. Both total delay and capacity impacts and individual movements are considered.
The history of incidents (collisions) at the location are also reviewed. This is of particular importance since some types of incidents (such as right angle or broadside) may be reduced in frequency with installation of a traffic signal. However, other types of incidents (such as rear end collisions) may increase with installation of a signal. When one street serves a much greater number of vehicles than the crossing street, the potential for an increase in the frequency of traffic incidents is higher.
Other considerations include growth trends, potential traffic diversions, where other future controls in the area may be likely and whether other changes may be more appropriate. The impact on overall traffic flow upstream and downstream of the signal is also of concern.
The warrants are included in the Manual on Uniform Traffic Control Devices (MUTCD) for Streets and Highways, and were established by the U.S. Department of Transportation (Federal Highway Administration). In addition, they are adopted by the State of Ohio as well as by the City Code. They are designed to ensure that traffic signals are installed only at intersections when they will be beneficial. The City staff adhere to these established standards and make signal installation decisions accordingly.
Procedure to Request a Traffic Signal
To request a traffic signal for a particular intersection, first contact the City Engineer and submit a request. The staff then schedules all needed studies and reviews the data for the location. If the location meets the criteria, a traffic signal is recommended by the staff, and installed as funding is made available.
When properly applied, traffic signals represent a sound public investment in the transportation system. A new traffic signal installation may cost $75,000 to $150,000.
Traffic Signal Misconceptions
People may request traffic signals based on misconceptions of traffic signal impacts. For example, persons may hear of one incident, especially if a fatality occurs, and conclude that a traffic signal should be installed. As previously stated, traffic signals do not necessarily reduce the frequency of incidents. In any case, making significant conclusions from a single or few incidents, especially without knowledge of the actual incident causes, can result in incorrect actions.
People may also request a traffic signal because it is difficult to cross or enter a busy street. If this alone were the reason for installing a traffic signal, busy arterials would have signals at almost all intersections and driveways, making travel extremely difficult. Sufficient traffic on cross streets is necessary to justify stopping major street traffic. The majority of miles traveled is on arterial streets. If cross streets were signalized at low traffic volumes, the few moments saved entering or crossing the major street would be lost many times over in travel along the arterial. In short, drivers are in the major street flow far more often than they are in the cross street flow. Even when the cross street volumes are sufficient to justify stopping the major street flow, the total delay to traffic may be increased.
Closely spaced traffic signals are of concern since they typically become more difficult to operate together and minimize stops and delays along major streets. Close spacing may result in gridlock when the line of vehicles from a signal backs up into other intersections. Diversion of traffic may also be a concern, especially if traffic is encouraged to use residential streets either to reach or avoid a signal.