## Obituaries: Gordon F. Newell

**June 10, 2001**

**Gordon F. Newell**, Professor Emeritus of Transportation Engineering at UC Berkeley and a pioneer in the field of transportation science and operations research, died on February 16 in an automobile accident near Carmel, California. He was 76.

A theoretical physicist and applied mathematician, Newell made contributions to solid-state physics and statistical mechanics in the 1950s, particularly in the areas of ferromagnetism and crystal behavior. While teaching at Brown University, he became interested in the dynamics of automobile traffic streams and wrote the first paper on traffic flow theory to appear in the operations research literature ("Mathematical Models of Freely-flowing Traffic Flow," *Operations Research*, Vol. 3, 1955). At the same time, he developed statistical formulas for delays at traffic signals ("Statistical Analysis of the Flow of Highway Traffic Through a Signalized Intersection," *Quarterly of Applied Mathematics*, Vol. 13, 1956) and later, using diffusion approximations, provided the first analytical solution for a more general class of traffic signal problems.

Newell established the relationship between the car-following and continuum theories of traffic flow dynamics, developed a comprehensive theory of traffic signal control, and showed how the most fundamental equations of traffic dynamics could be solved for inhomogeneous freeways. His contributions are milestones that shaped the field of traffic flow theory. His books on traffic flow---*Traffic on Transportation Networks* (MIT Press, 1980), *Theory of Highway Traffic Signals* (Inst. Trans. Studies, 1988), and *Theory of Highway Traffic Flow, 1945-1965* (Inst. Trans. Studies, 1995)---are a treasure trove of ideas and a model for scientific rigor.

His contributions to queuing theory are equally acclaimed. He introduced the idea of diffusion approximations in the 1960s, and these methods are now regularly used to solve the most complicated queuing problems. His book *Applications of Queuing Theory* (Chapman-Hall, 1971) is remarkable for the unconventional and practical way in which problems are approached, for the clarity of exposition, and for the broad applicability of the methodology. Equally impressive are three more advanced queuing monographs in which he systematically dissected several complex queuing systems that were previously thought to be intractable.

Newell was also known for introducing continuum approximations to the fields of scheduling and location theory. His paper "Scheduling, Location, Transportation and Continuum Mechanics: Some Simple Approximations to Optimization Problems" (*SIAM Journal on Applied Mathematics*, Vol. 25, 1973) is a classic that opened the door for the solution of a vast set of large-scale optimization problems. It has given a lasting impetus to the fields of transportation network design and logistics.

His influence on transportation theory did not stop with these seminal works. Gordon Newell was an excellent educator of advanced students, who in turn have made substantial scientific contributions. He was also an inspiration, role model, and mentor for innumerable scientists in the fields of operations research and applied mathematics.

Newell also made fundamental contributions in the areas of fluid dynamics (viscosity), stochastic processes, statistics (extreme value theory), public transportation systems, architecture (elevator system design), air traffic operations, and applied mathematics (asymptotic behavior of the multidimensional Schrödinger equation).

Newell was born in Dayton, Ohio, on January 25, 1925, and raised in Rochester, New York. He received a PhD in physics from the University of Illinois in 1950. After a three-year postdoctoral stint at the Institute of Fluid Dynamics and Applied Mathematics at the University of Maryland, he joined the applied mathematics department of Brown University in 1953. In 1965 he moved to the Civil Engineering Department at UC Berkeley, where he later became a member of the Industrial Engineering and Operations Research Department as well. He remained fully active after his retirement in 1991.

An avid ping-pong player, he played at noon in Berkeley's McLaughlin Hall courtyard with his graduate students and colleagues every day. He became the namesake for the annual ping-pong tournament (Newell's cup) in 1999.

Newell was a charter member of the International Symposium on Transportation and Traffic Theory (ISTTT) and an editor for SIAM and for the journal *Transportation Science*. The transportation science community honored Newell at the 12th ISTTT, held on the UC Berkeley campus, by dedicating the proceedings to him.

He is survived by his wife, Barbara Newell of Kensington, California; a daughter, Amy Pauly of Pleasanton, California; a son, Jeffrey Newell of Bangor, Maine; four grandchildren, Dale, Claire, Stewart, and Aubrey; and a sister, Ruth Holroyd of Rochester, New York

*Carlos Daganzo, Department of Civil and Environmental Engineering, University of California, Berkeley.*