MTI study: A majority of transit attacks occur during off-peak hours

To assist security planning, the Mineta Transportation Institute (MTI) today released a research report that identifies what time of day most attacks on public ground transportation in different parts of the world occur and when they are most lethal.

In their research, "Frequency and Lethality of Attacks on Surface Transportation Systems of Developed Countries by Time of Day," MTI Research Associates Brian Michael Jenkins and Bruce Butterworth analyzed more than 500 attacks on passenger-rail and bus systems in modern developed countries between 1970 and 2020.

They identified two categories of peak hours — average workday rush hours between 6 a.m. to 10 a.m. and 5 p.m. to 8 p.m., and holidays with high traffic and tourist travel— to determine how time of day of attacks affects lethality.

The researchers found that 63% of the attacks occurred in off-peak hours, as opposed to only 19% occurring during peak hours. However, the peak-hour attacks were 4.5 times more lethal. The timing of the remaining 19% of attacks is unknown.

To inflict maximum lethal damage, terrorists time their attacks to occur during weekday rush hours and peak travel times associated with holiday and vacation travel.

The research also found that the pattern of attacks on train targets is quite different from that of attacks on bus targets, with far more bus attacks occurring during non-peak hours.

The United Kingdom has the highest frequency of attacks (19% of the total), followed by Spain (16%), and then the United States (11%).

"Most U.S. attacks are carried out by mentally unstable individuals with no discernible pattern. There is a need for far more proactive alerts and treatments for these individuals rather than punishment," Butterworth said in a press release.

Not surprisingly, given the ability to acquire automatic and semi-automatic weapons in the United States, 14 of the attacks were armed assaults, explosives were used in 11 attacks, and 8 involved stabbings, representing more than 60% of all U.S. attacks.

"While not a wave of terrorism, U.S. anti-social violence is a disturbing trend that authorities must contend with while keeping an eye on terrorists," said Jenkins.

The MTI research comes in the wake of last week’s deadly mass shooting at a Santa Clara Valley Transportation Authority (VTA) rail yard in San Jose, California. On May 26, a VTA employee opened gunfire on his coworkers just after 6:30 a.m., killing nine of them. The gunman took his own life when he saw law enforcement officers at the scene.