People will pay more to reduce the amount of time they spend getting from one place to another, according to a principle known as “value of time.” So naturally, it would make sense that moving people faster would offer the same benefit. However, a new study suggests that increased speeds do not translate to shorter travel times and speed doesn’t have the same value as time.
Changed travel behavior during the COVID-19 pandemic has reduced congestion and vehicle miles traveled (VMT), even while traffic deaths continue to rise. Evidence shows that open roads, speeding, and other dangerous driving behaviors go hand-in-hand. But what is it about people that leads them to speed and drive dangerously in the first place?
Traffic volumes have plummeted since the pandemic. While that has led to fewer crashes overall in some states and cities, a growing number report large increases in speeding citations. In California, the number of tickets issued for driving above 100 miles per hour is 87 percent higher than this time last year. Similar reports have emerged across the country. Besides enforcement, what can states and cities do to reduce dangerous driving?
With overall traffic down due to the COVID-19 pandemic, one highway in Oregon is now moving higher traffic volumes at twice the typical speed, according to an analysis by Joe Cortright at City Observatory. This might seem counterintuitive, but it perfectly illustrates the benefits of managing traffic demand, based on simple traffic engineering principles.
The Oregon Transportation Commission last month approved a revised speed-limit guidance that abandons the long-standing-but-arbitrary 85th percentile rule in many cases. Instead of relying on drivers to set speeds by their behavior, the new guidance provides context-based safe speed ranges for urban and suburban roadways, ranging from 20-25 mph in urban cores to 25-35 mph in more suburban areas. The rule gives leeway for setting limits outside of those ranges. Rationales for exceptions do include observed motorist speeds, but they are based on the slower 50th percentile rather than the 85th.
As more data begins to emerge, COVID-19’s impact on traffic crashes and severity is proving complicated. Collisions and fatalities have declined in many places with data available, though not everywhere. However, collision rates and injury and fatality rates appear to be up in a number of cities for both drivers and vulnerable pedestrians once you account for the significant drops in VMT, likely due to higher speeds made possible by less traffic.
The 85th percentile rule in speed limit setting—an arbitrary but longstanding convention—has begun to weaken in recent years, with new guidance now allowing for lower speeds. FHWA’s USLIMITS2, for example, allows for speeds down to the 50th percentile in certain cases. Now there’s a growing push to take observed vehicle speed out of the speed limit equation entirely.
Dense development patterns offer important safety benefits, according to new research from the University of Pennsylvania, but high-speed roads in dense suburban centers are deadly for pedestrians. This new study confirms what others have already shown—that attention to context is critical to safe road design.
According to a recent study conducted by the Insurance Institute for Highway Safety (IIHS), in the past 25 years 37,000 additional people have died due to increased speed limits in the United States. Meanwhile, Canada is taking a very different approach to speed, as detailed in the April issue of ITE Journal, which is dedicated to safety through speed management.
When it comes to speed, delay and congestion usually get more attention than the flip-side problem of excessive speed. Under statute, for example, the federal government requires agencies to track speed reliability and delay. There is no similar requirement for tracking excessive speed, even though the data set provided for monitoring slow traffic could be used for fast traffic as well. However, the National Transportation Safety Board’s new 2019-2020 Most Wanted List, which it identifies as its “premier advocacy tool” in advancing transportation safety improvements, includes highway speed management in its Top 10 list.