The Tips and Tools to Successful Signal Timing Improvements Prevent Accidents and Traffic Delays: The Art of Delivering and Maintaining Successful Signal Timing Improvements The Tips and Tools to Successful Signal Timing Improvements By: Joshua H. Pack, P.E. joshua.pack@co.nevada.ca.us Distribution of the webinar materials outside of your site is prohibited. Reproduction of the materials and pictures without a written permission of the copyright holder is a violation of the U.S. law.

Meet Your Instructor BS Degree from the University of California - Davis Registered Civil and Traffic Engineer in California Principal Civil Engineer and County Traffic Engineer at the County of Nevada (CA) Previous experience as a Traffic Engineer for various SF Bay Area Municipalities Developing Traffic Signal Timing Strategies and Methodologies Intelligent Transportation System (ITS) Planning, Design and Construction Signal Coordination on Numerous Congested Corridors Signal Timing Review Maintaining Traffic Signal Systems Developing Consensus with Elected Officials and Key Policy and Decision Makers Public Outreach

Why Improve Signal Timing? Why develop traffic signal coordination in my jurisdiction? FHWA estimates that 75% of the nation’s 260,000 traffic signals could be improved by updating equipment or timing plans Poor signal timing accounts for up to 10% of all traffic delay in the United States Improve mobility and reduce travel times Reduce Greenhouse Gas (GHG) emissions and fuel consumption Reduce the number of collisions Reduce the total number of stops Reduce the number of complaints from local residents and improve customer satisfaction

Webinar Outcomes and Course Goal Bridge the gap between timing principals and real life application “Context sensitive” signal timing Steps to develop successful and sustainable timing improvements Key timing and coordination parameters and measureables that directly impact traffic safety and operations

Course Description Consensus building Developing realistic expectations Data collection Critical timing parameters Traffic inequity Infrastructure capabilities and limitations Signal timing improvements – the unintended side effects Microsimulation Intelligent Transportation Systems (ITS)

Course Description Testing and implementing timing improvements Develop regular system checks Public outreach and customer service

Case Studies and Lessons Learned Case Study 1 –County Supervisor Throws Wrench in Freeway Congestion Management Cast Study 2 –Happy Mayor and Council Thwart Timing Improvements

Step 1 – Public Outreach and Consensus Building What is the problem? Who is our audience? Elected officials and decision makers Residents Other members of the public How do we develop consensus? Engage your audience (public workshop, neighborhood meeting, etc.) LISTEN to their concerns / complaints Resolve issues within your control Develop consensus on the problem scope Developing realistic expectations Follow up through additional communication ESTABLISH TRUST WITH YOUR AUDIENCE!

Step 2 – Data Collection and Preliminary Scoping CRITICAL AT DEVELOPING REALISTIC EXPECTATIONS What is the scope of my project? What is the existing status of my intersection or corridor? What sort of planning level documentation will we ultimately develop? What are my project goals (collision reduction, operational improvements?) Traffic volumes Minimum AM/PM scenarios May want to consider other scenarios that may be corridor specific Lunchtime School peak Weekends Special Events Emergency

Step 2 – Data Collection and Preliminary Scoping Design and ITS Intersection geometrics for each intersection Existing field assets Controller equipment Detection equipment Other relevant cabinet equipment Communications infrastructure (fiber, copper, wireless, leased)

Step 2 – Finalize Size and Scope of Efforts What will be the size and scope of your project, and it is in conformance with the thoughts and desires of your elected officials? Will additional public outreach or workshops provide additional benefit? Identify costs and timeframe to develop and implement timing program Keep in mind potential Operation and Maintenance (O&M) costs DEVELOP REALISTIC EXPECTATIONS!!!

Step 3 – Developing Timing Improvements Not all trips are created equal! Hierarchical approach to signal timing Residents Businesses “Cut thru” traffic (perceived versus reality) Basic signal timing – you giveth and you taketh away Signal coordination Balance the needs for efficiency with the impacts to local residents and businesses

Signal Timing – Green Phase Timing Parameters Minimum Green (minimum initial) Consider 4 seconds minimum for all approaches Longer minimum green for through movements on major arterials Gap Extension (passage time, vehicle extension) Consider 2 seconds minimum for all approaches Longer extension timing for through movements on major arterials Maximum Green Simulation software can help identify appropriate max timing In absence of simulation software, minor approaches should serve traffic 95% of the time or more Major arterials should balance need to serve traffic with needs and expectations of minor approaches

Signal Timing – Yellow / Red Phase Timing Parameters Yellow Clearance Use of posted speed limit versus critical (85th percentile speed) 3.0 seconds minimum for all approaches Red Clearance Many jurisdictions require no red clearance interval Consider 1.0 second clearance interval uniform for all approaches Yellow + Red Clearance helps reduce intersection conflicts APPROACH SPEED YELLOW INTERVAL (mph) (seconds) 25 or less 3.0 30 3.2 35 3.6 40 3.9 45 4.3 50 4.7 55 5.0 60 5.4 65 5.8

Signal Timing – Other Timing Parameters Pedestrian Walk Clearance Intervals Bicycle Minimum Green Bicycle Clearance Intervals Dynamic Signal Timing Added initial green Variable gap extensions / gap reductions Dynamic maximum green timing Phase Recall Options Minimum / Maximum recall Pedestrian recall Dual entry / simultaneous gap Green / Pedestrian delay

Developing Traffic Signal Coordination Plans Size and complexity depends on the approach Use of microsimulation models (i.e. Synchro) Bad data = bad signal timing

Signal Coordination – Key Measureables Approach Delay and Approach LOS Queue Length 95th Percentile Total Delay Total Stops Fuel used Dilemma Vehicles Average Speed

Critical Timing Parameters Time of day (when does it makes sense to activate and deactivate coordination?) Corridors (and segments within corridors) Cycle length Split timing for each phase (amount of time each phase received in a given cycle) Timing preferences and traffic equity “Cut-thru” traffic and residential impacts

Microsimulation – Only the 1st Step! Pros Great at developing efficient network Are aware of local, state and federal signal timing standards Common pitfalls May employ “optimized” approach in favor of approach that balances public expectations May be unaware of localized traffic issues Reasonableness review Reliance on default values

EB I-580 Worst PM Commute in Bay Area Hopyard / Stoneridge intersection Oakland/SF San Jose/Fremont Concord/Walnut Creek Central Valley/Livermore

Blue – Local Traffic Yellow – “Cut Thru’ Traffic

Blue – Local Traffic Yellow – “Cut Thru’ Traffic

What is the role of ITS infrastructure? Pros Improve ability to implement traffic signal coordination Improve ability to monitor signal coordination Improve ability to troubleshoot and adjust coordination Implement emergency signal timing and coordination if needed Robust data collection possibilities Many devices now have ITS capabilities Video assets at key locations Sharing data and video with other agencies, departments, and the public Share cost sharing opportunities with partners – opportunities for public/private cost sharing? Cons COST! Significant increase in maintenance and replacement costs

Step 4 - Test and Implement Signal Coordination Activate and testing timing Fine tuning and observation “After” data collection

Step 5 – Follow up data collection and reporting Keeps members of the public, elected officials and decision makers informed of improvements Various data to consider including: Before and After travel time studies GHG emission reductions Reduction in number of stops Level of Service Overall delay Cut-thru analysis / volume comparison?? Consider delivering in a public setting (i.e. Council/Board meeting?) Goal is to quantify improvements of key measureables and educate your elected officials and decision makers

Step 6 – Now what????? Follow up data collection and recalibration Annually When major projects are constructed in the area Regular checks of field equipment Inquiries from the public When to consider changes or improvements?

Final Thoughts and Conclusions Signal timing and coordination can significantly improve corridor performance, reduce travel times, GHG emissions and collisions and provide a valuable service to your community. Recommend early public outreach to identify critical corridors and “hot spots” and to gain support from elected officials, key decision makers and the general public Data collection critical at developing signal timing and coordination plans and quantifying system improvements Key signal timing parameters can improve system operations and reduce the number of collisions Efforts do not stop and successful implementation OWNERSHIP!

End of Presentation Joshua H. Pack, P.E. Principal Civil Engineer / County Traffic Engineer County of Nevada – Department of Public Works (530) 265-7059 joshua.pack@co.nevada.ca.us

How to Obtain Webinar Certificate Visit www.asce.org/Webinars#policies and follow the brief instructions listed. Group attendees must use the “Order Number” – obtained from your Webinar Purchaser or Coordinator – to obtain a certificate.