June 3, 2013 - Whether or not you are aware of it, significant modifications have been made to standards and requirements for traffic signals in both the Federal and Ohio Manuals on Uniform Traffic Control Devices (MUTCD). While many of the changes do not include compliance dates, two sections that do contain target dates are worthy of the attention of every municipality. Updates to the Yellow Change, Red Clearance and Pedestrian Intervals require compliance within five years of the revision date (June 13, 2012) or when timing adjustments are made, whichever occurs first. While this five year window may seem large, some of the upgrades will require long-term planning, particularly in areas where the volume of traffic and the number of pedestrians are at high levels. As articulated in the Ohio MUTCD Manual, the revisions include:
- The duration of the yellow change and red clearance intervals are now required to be determined using engineering practices (OMUTCD – 4D.26)
- Due to slower average walking rates, the minimum walk and pedestrian clearance times has increased and a don’t walk buffer period has been added (OMUTCD – 4E.06).
These changes will impact the movement of traffic and, in urban areas, create a domino effect among consecutive intersections. Figure 4E-2 illustrates the pedestrian intervals and their possible relationships with associated vehicular signal phase intervals.
The City of Bryan Initiates Upgrade Program
Not a municipality to wait until the last minute, the City of Bryan decided to find out what it would take to achieve compliance with the new pedestrian timing requirements incorporated into the OMUTCD. The City contracted with DGL to study and develop timing plans for nine (9) intersections, all connected to Main and High Streets, the two primary thoroughfares through downtown Bryan. “It’s important that we plan ahead for these changes,” commented Brian M. Wieland, PE, PS, Bryan City Engineer. “The five year window gives us the opportunity to incorporate these updates gradually, which is easier on our annual budget.” All of the municipality’s current intersections operate on an 80-second background cycle when under coordination.
City officials provided existing timing data, crosswalk lengths, and traffic data. Timing plans were developed based on 1) a one hour count (provided by the City) at the highest volume intersection, Main & High Street; 2) crosswalk lengths; and 3) existing split balances at the remaining intersections using the established design standards.
Within ten days of receipt of the necessary evaluation data, DGL delivered to the City:
- Worksheets for each intersection that included evaluation data and recommended programming data
- Time-space diagrams representing the proposed modifications
- A one-page summary of the project and recommended modifications
DGL also recommended that an on-site evaluation of traffic flow be conducted after the changes have been accomplished in order to make sure the intersections function as intended and additional alterations are not required.
The City of Bryan expects to complete the programming changes this summer, well ahead of the compliance deadline.