Essays on Transportation Safety, Economics, and Policy
- Author(s): Scholl, Patricia Lynn
- Advisor(s): Raphael, Steven
- Reich, Michael
- et al.
The rational allocation of transportation resources involves both the evaluation of the effectiveness of programs designed to improve transportation systems, as well as the formulation of policies representing a balance of competing public interests in those systems. Such interests often include: curbing automobile emissions, expanding highway infrastructure, providing affordable transit services for inner-city residents, and extending commuter rail services to sprawling suburban areas. Designing policies that cost-effectively further each these objectives can attenuate the degree of inherent tradeoffs between them and expand the frontier of achievable policy goals. This dissertation presents a set of essays addressing two such aspects of transportation policy decisions: 1) an evaluation of programs aimed at increasing transportation safety and public health, and 2) an examination of the processes through which competing public interests and agendas are mobilized in the legislative arena by transportation agencies.
Chapter One: Graduated driver license programs (GDL), which progressively move teens through three stages of licensing while limiting driving to lower risk conditions, have become an increasingly popular approach in the past decade to address the high rate of teen driving related fatality and injury crashes. Teens are 2 to 6 times as likely as adults, per mile driven, to die in motor vehicle accident, and teen crashes tend to involve more fatalities per crash than for any other age group. Driving at night past 9pm or with young passengers under the age of 20 are significant risk factors for teen crashes.
This research uses a panel data set of teen driver involved fatal vehicle crashes among 16 to 17 year old drivers in 742 counties and 137 commuting zones straddling state borders for the years 1996 to 2009. I use a cross-state policy discontinuity design with an ordinary least squares fixed-effects regression model to identify the effects of graduated driver license laws on teen driver error related fatal crashes and associated fatality counts. Additionally, I analyze the impacts on crash characteristics most likely associated with teen driving mistakes, such as presence of young occupants and those occurring at night or involving alcohol. By taking into account local heterogeneities, the policy-discontinuity design provides more credible identification than previous studies. Importantly, the findings indicate much larger GDL effects than in the extant literature.
I find that the strongest GDL programs, as rated by the Insurance Institute for Highway Safety, reduce teen driving related fatal crash rates by 25 to 34 percent and teen driving error related fatal crash rates by 34 to 45 percent. The most effective components of the GDL were early nighttime driving curfews beginning between 6pm to 10pm at night. Passenger restrictions had statistically significant effects only when controlling for the number of licensed teens on the road. For example, the zero to one passenger limit reduced quarterly county-level young teen driver involved fatal crash rates per 100,000 by -6.388 points, relative to a mean rate of 9.5 in state-periods without restrictions. These passenger limits were also highly effective at reducing nighttime crashes among teens, with a reduction in these crash rates of -5.909. Finally, the extended practice period during which newly licensed teens are only allowed to drive under adult supervision were effective in reducing fatal crashes per unit population but only were statistically significant for nighttime crashes that occur after 9pm when controlling for the number of licensed teen drivers.
Chapter Two: Government transportation agencies spend considerable amounts of money attempting to influence state and federal legislation, through their own legislative staff, and the efforts of appointed officials and hired lobbyists. Almost none of the literature to date has examined how transportation agencies use their funding and political influence to shape state and federal policy. By looking at what topics agencies choose to lobby on, or not to lobby on, we can better understand how transportation agencies attempt to shape the transportation legislation, and how potential biases in their agendas are mobilized. This analysis includes four agencies in the San Francisco Bay Area Metropolitan region: the Metropolitan Transportation Commission (MTC), a regional Metropolitan Transportation Planning Organization, the Bay Area Rapid Transit District (BART), the region's commuter rail operator, Alameda-Contra Costa Transit (AC Transit), a local bus agency serving two counties in the East Bay, and the Santa Clara Valley Transit Authority (VTA), a bus and light-rail transit operator in the southern portion of the region. Collectively, these four agencies account for approximately 80 percent of the total spending on lobbying activities by San Francisco Bay Area transportation agencies.
This research draws on government reports filed by the agencies, in-house agency legislative agenda records, and interviews with legislative and agency staff. Descriptive statistics and a probit analysis of lobbying data are applied to compare the substance of each agency's lobbying activities to the set of pressing transportation issues the agencies themselves have identified in their planning documents, and the set of transportation issues and needs identified by other key stakeholders including business groups, social justice advocates, and environmentalists. All of the transportation agencies lobbied heavily for finance bills that increase revenue and flexibility in fund use as well as funding redistribution. Equity related bills that address transportation for low-income populations have a significantly higher marginal probability of gaining both MTC and AC Transit support, relative to bills that do not address these issues. Overall, VTA was less likely to support highway bills but did not have biases toward any other particular bill issues. BART overwhelming supported bills promoting smart growth principles and transit oriented development, two strategies believed to increase transit ridership. Both the Santa Clara VTA and BART were strategic in the bills they chose to support, having a greater likelihood of supporting bills authored by transportation committee chairs, perhaps in an effort to both build political capital and to expend resources on bills with a greater chance of passage. MTC was more likely to take a supporting position on social equity related bills; however, the degree of effort in that support is unknown. Notably, MTC was not statistically more likely to support bills specific to expanding public transit, a mode important to low income groups, relative to other bill categories.