rounding the corner

November 2013 Volume 53 Issue 4

ROUNDING THE CORNER: AMHERST SOLVES TRAFFIC AND SAFETY ISSUES WITH UNIQUE TWIN ROUNDABOUT SUBMITTED BY: LARRY J. MURPHY, P.E. LISA D. SHERMAN, P.E., PTOE

The New England Chronicle

12

Student Research Spotlight:

ANDREW L. BERTHAUME, E.I.T., M.S.C.E.

Doctoral Degree Candidate University of Massachusetts Amherst

Roundabout Impacts on Transit Operations: How the Introduction of a Roundabout Helped Improve Transit Reliability With over 3,500 new installa ons since 1990, the modern roundabout is becoming a widespread alterna ve to signalized and stopcontrolled intersec ons in the United States1. Mul ple studies highlight the opera onal benefits of roundabouts, indica ng that many intersec ons have seen a reduc on in total delay, reduced lane requirements, and in most cases an increase in intersec on capacity2,3. Replacing stop signs or traffic lights with yield signs minimizes stopped- and start-upme delay4,5. On average, intersec ons with roundabouts see a 30 to 50 percent increase in traffic capacity compared to their signalized counterparts6. UMass Transit Services (located on campus at the University of Massachuse s, Amherst), a contracted provider of public transporta on for the Pioneer Valley Transit Authority (PVTA), has grown to service more than 2,800,000 passengers a year in over 9 communi es7,8. This award-winning service promotes ridership through “fare free” service and by maximizing user benefits, providing rider accommoda ons such as busmounted bicycle racks (to promote mul modal ridership)8. UMass Transit understands the importance of promo ng ridership to provide commuters with a safe, reliable, and efficient alterna ve to driving; op mizing

Figure 1: LocaƟon of UMass Roundabout (Source: Google Earth) transit is a cornerstone solu on in addressing growing capacity needs9. UMass Transit Service buses are dispatched from their garage on campus. Many UMass Transit bus routes pass through the intersec on of Governor’s Drive, Eastman Lane, and North Pleasant Street at the northeastern corner of the UMass campus. Prior to 2010, this intersec on was pre- med,

signal-controlled. The pre- med signal caused excessive queues during commuter and student peak hours of the day, and intersec on opera ons were unable to accommodate fluxes in traffic volumes that occurred throughout each day10. These queues caused significant delays for buses whose routes traversed the intersec on, ConƟnued on Page 13

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November 2013 | Volume 53 | Issue 4

13 “improved transit reliability” could arguably be a benefit worth emphasizing when proposing to build a new roundabout along a transit route. References 1

www.roundaboutsusa.com Rodegerdts, L. A., W. E. Scarbrough, and J. A. Bansen. (2010). Technical Summary on Roundabouts. Report No. FHWA-SA-10-006. Federal Highway Administra on, Washington, D.C. 2010. 3 Rodegerdts, L., J. Bansen. C. Tiesler, J. Knudsen, E. Myers, M. Johnson, M. Moule, B. Persaud, C. Lyon, S. Hallmark, H. Isebrands, R. B. Crown, B. Guichet, and A. O’Brien (2010). Roundabouts: An Informa onal Guide, Second Edi on. Na onal Coopera ve Highway Research Program Report 672. Transporta on Research Board, Na onal Academy of Sciences, Washington, D.C., 2010.  Russell, E. R., and S. Mandavilli (2004). “Can Modern Roundabouts Safely Accommodate All Users?” Technical Paper in the ITE 2004 Annual Mee ng and Exhibit Compendium, Ins tute of Transporta on Engineers, Lake Buena Vista, Florida, August 1-4, 2004  (2005) Roundabout Design Standards: A Sec on of the Traffic Engineering Policy & Design Standards. Rep. City of Colorado Springs: City of Colorado Springs – Transporta on Engineering, October 4th, 2005. Print.  Roundabouts New Tools for Safe Driving. Elkhart, Marshall and St. Joseph Coun es: Michiana Area Council of Governments. Online. 7 UMass Transit Passenger Counts, FY 2000-2013 8 UMass Transit Services. h p://www.umass.edu/ transit/  Gehr, David (2010). Unlocking Gridlock. American Associa on of State Highway and Transporta on Officials, 2010. 10 North Pleasant Street at Governors Drive/Eastman Lane, Amherst MA. Func onal Design Report. Watertown, MA: Vanasse Hangen Brustlin, April 2010. PDF 11 Phone interviews and Email correspondence with Glenn Barrington, Interim Director of UMass Transporta on Services. Conducted 7/1923/2013  Perk, Victoria; Jennifer Flynn; and Joel Volinski (2008). Report No. NCTR-776-07 Transit Ridership, Reliability, and Reten on. Final Report. Na onal Center for Transit Research, Center for Urban Transporta on Research. University of South Florida. October. FDOT BD-549-32. 13 Roundabout Construc on Phasing. North Pleasant Street Roundabout Phasing. DRAFT 4/16/10 2

Figure 2: UMass Roundabout from top of Lederle Tower (Source: UMass Amherst) ConƟnued from Page 12 reducing transit reliability11. Studies have indicated that reliability in public transit and on- me performance can have a significant impact on current and prospec ve transit ridership12. Therefore, the reduced transit reliability caused by these intersec on delays could nega vely impact UMass Transit Service’s ridership. In 2010, the pre- med, signal-controlled intersec on of Governor’s Drive, Eastman Lane, and North Pleasant Street was redesigned as a four approach roundabout13. The redesigned intersec on be eraccommodated bicyclists and pedestrians, while reducing average peak-hour delays at the intersec on from 33 seconds to 9 seconds, and average peak hour queues from 22 vehicles to 710. UMass Transit Services experienced opera onal benefits with the introduc on of the roundabout. Without excessive queue development at the formerly signalized intersec on, the transit service saw massive improvements in reliability. Glenn D. Barrington, Interim Director of UMass Transporta on Services explained these impacts through a series of emails and phone interviews, sta ng that buses were able to remain on- me because they were no longer affected by excessive intersec on delays caused by daily fluxes in traffic11. With the addi on of the roundabout, UMass Transit was now able to improve their reliability, further promo ng ridership for an

already successful bus service. Between FY 2009 and FY 2013, ridership improved by 4.11 percent, servicing a UMass Transit record of nearly 3 million passengers between July 2012 and June 20137. Barrington says the increased ridership could be caused by any number of factors (including weather condi ons and gas prices), and is not necessarily a ributed to the addi on of the roundabout; however, he agrees that the roundabout has significantly improved transit reliability and bus opera on through the intersec on11. Barrington met frequently with project managers and engineers who advised UMass Transit about the improved turning radius and reduced delay at the intersec on; however, poten al improvements to transit reliability was not directly men oned in reports10,11. In conclusion, we know how the modern roundabout can benefit bus services through improved turning radius and reduced delay, but seldom do we inves gate impacts on reliability, and poten al subsequent improvements in transit ridership. In the case of UMass Transit, the replacement of a premed signal with a roundabout facilitated a more reliable transit service, and a significant ridership increase was observed a er the addi on of a roundabout. A possible correla on between these two events should be inves gated, and other case studies should be considered before any defini ve conclusion is drawn. For the me being, we can safely state that

The original report has been modified for this newsle er. To receive a copy of the original report, for more informa on, or to express any ques ons, comments, or concerns regarding this ar cle, please contact: Andrew L. Berthaume, E.I.T. at $QGUHZ%HUWKDXPH#GRWJRY Andrew L. Berthaume, E.I.T. is a Civil Engineering PhD Candidate at the University of Massachuse s Amherst, and is a Community Planner Pathways Student Trainee at the Volpe Center in Cambridge, MA.

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