New research from the Mineta Transportation Institute (MTI) 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 R. Butterworth analyzed over 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 (6am-10am and 5pm-8pm) and holidays with high traffic and tourist travel — to determine how time of day of attacks affects lethality.

Jenkins and Butterworth found that approximately 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 (numbers may not sum up to 100 due to rounding).

“It seems logical that terrorists seeking to cause maximum disruption or mass casualties would launch their attacks during times of day when passenger traffic is at its height. However, some attackers — left-wing groups and Basque separatists, for example — have avoided large-scale casualties and have generally carried out their attacks during off-peak hours, often at night to avoid detection,” Jenkins said.

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 U.K. has the highest frequency of attacks (19% of the total), followed by Spain (16%), and then the U.S. (11%).

According to Butterworth, “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.”

Not surprisingly, given the ability to acquire automatic and semi-automatic weapons in the U.S., 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,” Jenkins said.

The forensic detail provided by this research, along with the quantification and analysis of the data associated with attacks on public transport during rush hours, can help anyone involved improve safety and security planning and potentially save lives. Ultimately, these findings can help establish timelines and attack patterns, which can be used for security and planning and aid those responsible for running and overseeing transit operations to prioritize visible and remote security presence and quick response to attacks on transit systems.