Personal tech usage has become synonymous with the modern travel experience - a way to tune out the crazy and dive into a wholly customizable personal experience.
Anecdotally, it would seem that device usage is consistent across all forms of transportation as any long distance movement from A to B is an ideal opportunity to engage with personal technology. However, last week's annual update to the "Personal Tech Tidal Wave" study by De Paul University has found that usage gains in personal technology are primarily isolated to discount bus users.
The results were determined by visually observing 7,034 passengers on weekday departures via 20 commercial flights within the USA, 20 intercity Amtrak trains, 12 conventional intercity bus departures (Greyhound), 20 curbside bus departures, and 36 commuter trains in the Chicago area.
The study is by no means wholly comprehensive as far as representing a statistically relevant group of passengers, but is an interesting slice of life for the average device-engrossed traveler.
This uptick in usage on discount buses is likely driven by the perfect combination of new route proliferation and the availability of free WiFi on board. Trains and planes don't generally offer free WiFi as a value add, thus the discrepancy.
Amtrak trains do often have complimentary WiFi, but in this writer's experience it is quite sluggish and unreliable. Performance issues lead to a reduction in reliance on Internet functionality of personal tech devices, which is backed up by the observed data.
The ability to use mobile devices as phones, in addition to taking advantage of 3G/4G/LTE, likely also influences the usage on bus and trains, as does the convenient in-seat plugs on these modes of transportation.
The overall plateau of device usage over time on Amtrak and airlines is especially thought-provoking.
Could it be that there is indeed a set number of passengers that will choose not to use devices on these modes of transport? Will the relaxed FAA rules lead to a renewed increase as travelers habituate themselves to the loosened regulations? Are discount buses succeeding in slicing off the more tech-savvy who don't want to deal with the security hassles of flying?
Some of this discrepancy is explained in the study as related not just to usage but intensity of said usage:

It warrants emphasis that a greater share of passengers—perhaps more than 80%—use electronic devices at some point during their trips. By looking at usage rates at particular moments in time, however, the approach used in this report provides a more accurate portrayal of the intensity of technological engagement than studies focusing only on whether a device is being used at some point during the trip.
The latent effects of the recent relaxation of FAA rules - which only happened in January of 2014 - might indeed mean an overall increase next year.
Another sign pointing to a potential increase in device usage on planes is the prediction that tablets will outsell laptops at some point in 2015. Tablets continue to be the most popular means of tech engagement while flying, with one in 8 observed travelers using the devices (compared on the other end with 1 in 24 on intercity discount carriers).
The full report lives here.
NB: Chicago train junction image courtesy Shutterstock.