Portland State University

When engineers focus on transportation systems, they often produce brilliant solutions. Sometimes, however, they focus in the wrong place.

 “Engineers are really good; if you tell them, ‘This is what we want to accomplish,’ they’ll do it,” said Peter Jacobsen, himself an engineer and a public health consultant. “But traffic safety hasn’t had a good scientific, evidence-based approach that we have in, say, nuclear-power-plant design.”

Jacobsen, Portland State University’s first visiting scholar this school year, will present the Vision Zero concept at Friday’s transportation seminar. Vision Zero resets the goal of transportation systems from reducing total crashes to eliminating fatalities.

“The way engineers currently look at the road system is to look at crashes,” Jacobsen said. “Vision Zero folks say to look at health: not to have fatalities or permanent disabling injuries.”

Designing for health means respecting the limits of the human body. If crossing into oncoming traffic could produce head-on collisions with a greater force than people could survive, then Vision Zero says to separate that traffic. Roundabouts reduce the likelihood of dangerous side-impact collisions.

Vision Zero could have the largest effect closer to home. Jacobsen has pushed for colleagues to consider traffic from a child’s perspective. A residential street that might be...

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Summary: A growing concern related to large-truck crashes has increased in the State of Texas in recent years due to the potential economic impacts and level of injury severity that can be sustained. Yet, studies on large truck involved crashes highlighting the contributing factors leading to injury severity have not been conducted in detail in the State of Texas especially for its interstate system.  In this study, we analyze the contributing factors related to injury severity by utilizing Texas crash data based on a discrete outcome based model which accounts for possible unobserved heterogeneity related to human, vehicle and road-environment. We estimate a random parameter logit model (i.e., mixed logit) to predict the likelihood of five standard injury severity scales commonly used in Crash Records Information System (CRIS) in Texas – fatal, incapacitating, non-incapacitating, possible, and no injury (property damage only). Estimation findings indicate that the level of injury severity outcomes is highly influenced by a number of complex interactions between factors and the effects of the some factors can vary across observations. The contributing factors include drivers’ demographics, traffic flow condition, roadway geometrics, land use and temporal...

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