Are Americans’ travel choices truly safe or efficient?

Safety and efficiency. These two concepts constitute the primary goals of the planning and operation of transportation systems. While transportation serves as the backbone of the economy and has a host of impacts, positive and negative, on people’s lives and livelihoods, the only factors that most people consider on a daily basis when deciding how to travel are “Is it safe?” and “Does it get me (or the goods I’m shipping) to my destination quickly?” At least the conventional wisdom amongst those who study transportation economics is that people only consider those two factors. Safety and efficiency are measurable, but the results one gets depend on how one defines “safe” and “efficient.” Safety is generally defined by the absence of death or injury to passengers and of damage or destruction of goods. And though there are many possible definitions of efficiency, the one that is generally considered is travel time.

The degree to which these two concepts are effective ones for economists, planners and transportation system managers to focus on was the subject of last night’s discussion in one of my courses in George Mason University’s Master of Arts in Transportation Policy, Operations and Logistics program. The class reviewed the analysis that our professor, Dr. Edmund Zolnik, performed (in a not-yet-published paper) of national household survey data from 2001 and 2009 to determine the effect of two factors — the relative fuel-efficiency of one’s car and the amount of new road capacity added in one’s region — on how long (time) and how far (distance) one drove to and from work. The results showed that the time people spent commuting by car hardly changed at all, in spite of the Great Recession’s stagnating effect on people’s ability to relocate or change jobs, and that the average distance people drove to and from work increased only slightly.

So what does this have to do with trains, you may ask? For those of us interested in promoting transit (primarily rail, but also bus) as an alternative to driving, it is helpful to know what factors influence people’s daily travel decisions and to what degree. The unfortunate fact is that using public transportation (if it is an option at all) simply takes longer than driving for most trips in the US, and for those who are able to and can afford to drive, this fact alone is usually a deal-breaker. (There is, however, a sizable chunk of Americans, including seniors, who are physically or monetarily unable to drive for whom having other ways of getting around is an even more basic matter of accessibility.) This situation is largely due to how our communities have developed over the last half century thanks to cheap petroleum and policies that favored road building and disfavored investments in transit. The spread-out development patterns that resulted make it very difficult and costly to provide an attractive level of transit service (coverage and frequency) to many places, particularly suburban areas.

So lack of accessibility affects the efficiency (in terms of travel time) of transit as an alternative to driving. But there are other measures of efficiency. In terms of the fuel-efficiency, and thus the cost of fuel, of trips on a per-passenger-mile (one passenger traveling one mile) basis, cars would be comparable to trains and buses if most cars had three or four passengers. But the fact is that the vast majority of car trips are taken by the driver alone (see page 47). Therefore, one uses less fuel when traveling by train and bus than when one drives, even with relatively light bus and train load factors. Robust transit service — particularly rail — also goes hand-in-hand with denser development patterns that allow all manner of public and private resources — from police and fire protection to water and sewer infrastructure, to even cars, when they are needed — to be used more efficiently (at a lower cost per use).

And what about safety? Even though studies show the relative possibility of death or injury to be one of people’s key considerations in travel, being in a car remains one of the most dangerous activities many people undertake on a daily basis. During the 1990s and early 2000s, there were 7.2 fatalities per billion passenger miles traveled by car. This is fairly low number, but it is 15 times as many deaths per billion passenger miles traveled as there were amongst train passengers during the same period (0.5 fatalities per billion passenger miles traveled by train). 2011 saw the fewest motor vehicle deaths on US roads in recent history: 32,367 deaths (still a very high number), compared to 570 railroad fatalities (only a very small number of those being passengers).

Nevertheless, it’s going to take more than rising gas prices and worsening highway congestion in metropolitan areas to make a dent in Americans’ over-dependence on cars and make transit more accessible in more places. But trends are already starting to move in that direction, especially among younger Americans. Growing awareness of the other factors in the transportation equation besides travel time, and of the many indirect ways we are all paying the costs of being too reliant on one form of travel to the exclusion of others, will come to make the necessary paradigm shift amongst policymakers more palatable.