Smart Car Researcher Wants to Eliminate Stoplights

<img src="https://spectrum.ieee.org/media-library/a-middle-aged-greek-man-with-facial-hair-smiling-against-an-illustrated-street-map-background.jpg?id=68036422&width=1245&height=700&coordinates=0%2C187%2C0%2C188"/><br/><br/><p><a href="https://christosgcassandras.org/" rel="noopener noreferrer" target="_blank">Christos Cassandras</a> has spent more than 40 years studying how computers and machines make decisions. Lately, his work has focused on a problem nearly every driver knows well: sitting at a red light with no cross traffic in sight, wondering why it takes so long for the light to turn green.</p><p>Cassandras, an IEEE Life Fellow, is a professor at <a href="https://www.bu.edu/" rel="noopener noreferrer" target="_blank">Boston University</a>, where he headed its <a href="https://www.bu.edu/eng/academics/departments-and-divisions/systems-engineering/" rel="noopener noreferrer" target="_blank">systems engineering division</a>, a graduate program he helped create.</p><h3>Christos Cassandras</h3><br/><p><strong>Employer</strong> </p><p>Boston University</p><p><strong>Title</strong> </p><p>Professor</p><p><strong>Member grade</strong> </p><p>Life Fellow</p><p><strong>Alma maters</strong> </p><p>Yale, Stanford, and Harvard</p><p>He is the recipient of this year’s <a href="https://ieee-itss.org/" rel="noopener noreferrer" target="_blank">IEEE Intelligent Transportation Systems Society</a><a href="https://ieee-itss.org/awards/outstanding-research/" rel="noopener noreferrer" target="_blank"> Outstanding Research Award</a> for his work on <a href="https://spectrum.ieee.org/tag/autonomous-vehicles" target="_self">autonomous vehicles</a> and the systems that help them drive—work that could one day get rid of traffic lights altogether.</p><p>That idea—proving with mathematical models and intelligent algorithms using cars’ relative speeds, mass, and distance as inputs that self-driving cars will behave safely before they are ever let loose on the streets—has become the foundation of Cassandras’s career and the reason his name keeps coming up in conversations about transportation.</p><p>In the 1990s he theorized that a machine such as a car could be understood as two things at once: an object obeying the laws of physics and a computer processing information and making decisions. This led to what we now call cyber physical systems. That framework is still the standard way engineers describe a car’s mechanical behavior.</p><p>“Ultimately, the key word is <em><em>safety</em></em>,” Cassandras says. “You would not buy a self-driving car unless the manufacturer could guarantee that it’s safe for you.”</p><h2> Growing up in Greece during a dictatorship</h2><p>Born in Athens, Cassandras was a teenager during<a href="https://www.britannica.com/topic/the-Colonels" rel="noopener noreferrer" target="_blank"> Greece’s military dictatorship</a>, a period he says scarred him and many others but also taught him some hard lessons. His father was a partner in an insulation manufacturing company, and his mother was a homemaker.</p><p>His friends pulled Cassandras toward engineering. As a teenager, he ran with a group of classmates who read about philosophy, history, and science. They were especially struck by the <a href="https://airandspace.si.edu/explore/stories/apollo-11-moon-landing" rel="noopener noreferrer" target="_blank">1969 Apollo 11 moon landing</a> and the questions it raised about the technology that made it possible.</p><p>That same year also marked the <a href="https://www.icann.org/en/blogs/details/the-first-message-transmission-29-10-2019-en" rel="noopener noreferrer" target="_blank">first time a piece of data was sent from one computer to another</a>—an early step toward the creation of the Internet. Several inspiring teachers pushed his curiosity about technology even further.</p><p>He was awarded a scholarship to study in the United States, and he enrolled at<a href="https://www.yale.edu/" rel="noopener noreferrer" target="_blank"> Yale</a>, where he first studied physics and philosophy before switching to engineering. He earned his bachelor’s degree in engineering and applied science in 1977. At the time, Yale didn’t yet offer separate degrees in fields such as electrical or mechanical engineering.</p><p>From there, Cassandras went to <a href="https://www.stanford.edu/" rel="noopener noreferrer" target="_blank">Stanford</a>, earning a master’s degree in electrical engineering in 1978. There, he became interested in <a href="https://en.wikipedia.org/wiki/Game_theory" rel="noopener noreferrer" target="_blank">game theory</a>, the mathematical study of decision-making and strategy.</p><p>A mentor pointed him to <a href="https://www.harvard.edu/" rel="noopener noreferrer" target="_blank">Harvard</a>, home to a leading game theory researcher at the time. His new mentor, Professor <a href="https://seas.harvard.edu/person/yu-chi-ho" rel="noopener noreferrer" target="_blank">Yu-Chi “Larry” Ho</a>, now an IEEE Life Fellow, advised him to abandon game theory, which Ho considered a scientific dead end at the time. Ho suggested a newer, less-explored area of research, that of emerging dynamic systems in modern technology whose behavior could be understood and managed through occurrences of discrete events.</p><p>Cassandras took the advice. He earned a second master’s degree from Harvard the following year and completed his Ph.D. in applied mathematics there in 1982. He and Ho remain friends and colleagues.</p><h2> Fiat assembly line births of a new kind of engineering</h2><p>Ask people in <a href="https://ieee-itss.org/" rel="noopener noreferrer" target="_blank">intelligent transportation systems</a> circles why Cassandras’s name carries so much weight, and the answer traces back to a theoretical shift he helped pioneer starting in the 1980s. Cassandras recognized that human-made systems—computers, factory machines and, eventually, vehicles—operate on a different kind of logic than the one that governs the natural world.</p><p>The physical world runs on time-driven physics, the same math <a href="https://www.britannica.com/biography/Isaac-Newton" rel="noopener noreferrer" target="_blank">Isaac Newton</a> used centuries ago. But machines built by people, he realized, are better understood as event-driven: They mostly sit still until something happens, like a button click or a part arriving on a conveyor belt.</p><p>That insight didn’t come from a textbook. It took shape during Cassandras’s early graduate work, when he was handed a real-world problem. He was assigned to figure out how to manage the buffers—the temporary holding areas for car parts—on an assembly line for <a href="https://www.fiat.com/" rel="noopener noreferrer" target="_blank">Fiat</a>, the Italian carmaker.</p><p>Solving that concrete, practical puzzle helped him see how event-driven thinking could describe an entire class of systems that classical physics-based math couldn’t handle well. This came to be known as <a href="https://link.springer.com/book/10.1007/978-3-030-72274-6" rel="noopener noreferrer" target="_blank">discrete event systems</a><em><em>.</em></em></p><p>By the early 1990s, that insight had matured into a formal framework: hybrid systems theory, now known as <a href="https://en.wikipedia.org/wiki/Cyber-physical_system" rel="noopener noreferrer" target="_blank">cyber physical systems</a> theory. The idea is that a machine can be understood as an object obeying the laws of physics and as a computer obeying event-driven dynamics.</p><h2>Building “event-driven” systems</h2><p>After completing his doctorate, Cassandras wanted to test himself outside of academia. He spent about a year and a half as a systems engineer at Information and Technology for Production (ITP), a small manufacturing-automation startup in the Boston area. The experience convinced him that the “real world” wasn’t so different from academic life, and he returned to research while continuing to consult for the company for roughly a decade. He has kept up the habit of staying connected to industry throughout his career.</p><p>In 1984 he joined the <a href="https://www.umass.edu/admissions/first-year-students?utm_campaign=bvk-7134_umass_search_fy27admissions_brand_newyork&utm_medium=paidsearch&utm_source=google&utm_term=university%20of%20massachusetts%20amherst&utm_content=bvk-706915381353&gad_source=1&gad_campaignid=21490020363&gbraid=0AAAAAo2qFQxIzla1V5lpfXZHpK4qipiY3&gclid=CjwKCAjwzNTUBhAjEiwA7zcvWu8D6YmKbwxYUZDSKywzAJpLhc_eVOsRla2-nnwEb05i-qaZFsnipRoC9c0QAvD_BwE" rel="noopener noreferrer" target="_blank">University of Massachusetts Amherst</a> as a faculty member in the <a href="https://www.umass.edu/engineering/electrical-and-computer-engineering" rel="noopener noreferrer" target="_blank">electrical and computer engineering department</a>. Building on the ideas born out of the Fiat project, he helped pioneer research into event-driven systems.</p><p>That was a shift away from the traditional math used to describe the physical world toward systems built around discrete events. The transition, driven by the rise of computers, became the backbone of Cassandras’s research for the next three decades.</p><p>In 1997, after years of commuting weekly between Amherst and Boston for his consulting work, he joined Boston University as a tenured full professor in what was then its manufacturing engineering department. As the field evolved in the early 2000s with the rise of the Internet and sensor technology, Cassandras helped establish the university’s systems engineering division. In 2008 he became the research program’s first director, a role he held until stepping down two months ago.</p><h3> Using math to show that self-driving cars are safe</h3><p>Cassandras’s recent research has focused on mathematically proving vehicle safety before a car is road-tested. He has developed models built around measurable quantities: a vehicle’s position, speed, and distance to nearby vehicles. That lets connected and automated vehicles cooperate during tricky maneuvers such as changing lanes on a highway in traffic.</p><p>He has extended the approach to a bigger idea: eliminating traffic lights. One of his more striking projects involves a chronically congested intersection near his office in Boston, where Commonwealth Avenue meets the <a href="https://secretboston.co/bu-bridge-boston/" rel="noopener noreferrer" target="_blank">Boston University Bridge</a>. Using<a href="https://en.wikipedia.org/wiki/Traffic_simulation" rel="noopener noreferrer" target="_blank"> computer simulations</a>, he and his team modeled what would happen if they removed all the traffic lights, and cars simply coordinated with each other instead. The results, he says, showed improvements not only in how smoothly traffic would flow but also in safety and energy efficiency.</p><p>Cassandras acknowledges that widespread adoption is still far off. For now, only a small percentage of vehicles on the road are capable of that kind of communication. But he’s testing similar coordination systems using small robots in his BU lab, working to bring the idea closer to reality and to exploit the intelligence of cooperating autonomous vehicles even when they are only a small fraction of the actual cars on the road.</p><p>He says his perspective has evolved in recent years from viewing humans as obstacles to smooth automation toward designing technology that actually works for people.</p><p>Through projects with Boston on <a href="https://www.bu.edu/articles/2013/if-boston-were-smart-2/" rel="noopener noreferrer" target="_blank">smart city</a><em> </em>initiatives, he learned that not everyone can afford or access new technology—a lesson that reshaped how he approaches his research.</p><p>“It’s not just about technology,” he says. “It’s really about technology and people.”</p><h2>A legacy passed on through his students</h2><p>His influence in the field has been amplified by some of his students. Several of his Ph.D. students have developed safety algorithms at companies including <a href="https://www.aptiv.com/" rel="noopener noreferrer" target="_blank">Aptiv</a> and <a href="https://zoox.com/" rel="noopener noreferrer" target="_blank">Zoox</a>,<em> </em>both of which build technology for autonomous and connected vehicles. He wrote a book, titled <a href="https://link.springer.com/book/10.1007/978-3-031-27576-0" rel="noopener noreferrer" target="_blank"><em><em>Safe Autonomy with Control Barrier Functions: Theory and Applications</em></em></a><em><em>, </em></em>with one of his former students. It lays out the mathematical foundations of autonomous-vehicle safety, with specific applications to intelligent transportation.</p><h2>A long relationship with IEEE</h2><p>Cassandras joined IEEE as a student member while he was a graduate student. He was drawn in by the discounted student conference registration fees, he says.</p><p>That early, practical decision grew into something bigger: a professional community with which he has stayed connected for more than 40 years.</p><p>He has served as president of the <a href="https://ieeecss.org/" rel="noopener noreferrer" target="_blank">IEEE Control Systems Society</a>, his primary professional home within IEEE. He has served on the <a href="https://www.ieeecss.org/publications" rel="noopener noreferrer" target="_blank">conference publications committee</a> and is currently involved with <a href="https://spectrum.ieee.org/ieee-publishing-ethics-research-integrity" target="_self">IEEE Publishing Ethics.</a></p><p>IEEE’s greatest value to his career, he says, has come through the relationships he has built at its conferences and serving on committees. Connections with colleagues and IEEE leadership have shaped his thinking and opened doors throughout his career, he says.</p><p>Looking back on more than four decades of work, Cassandras says the goal has never really been about the technology for its own sake.</p><p>“After all,” he says, “we’re doing all this to make society better and facilitate the comfortable lives of all of humanity.”</p>