Using Cost-Effectiveness Analysis to Prioritize Spending on Traffic Safety
Dec 14, 2015
|PDF file||3 MB||
Use Adobe Acrobat Reader version 10 or higher for the best experience.
Motor vehicle crashes are a leading cause of death in the United States. In 2013, 32,719 deaths and 2.3 million nonfatal injuries occurred. Crashes are also expensive; in 2010, according to a 2015 study, they resulted in more than $836 billion in economic loss and societal harm. Property damage, medical expenses, emergency services, and other fees related to crashes cost taxpayers over $242 billion — which is equal to about $765 for each person living in the United States.
Fortunately, state health, transportation, and safety officials can choose from a wide range of evidence-based interventions to reduce the social and economic harms related to motor vehicle crashes. Interventions include policies and programs, including primary enforcement seat belt laws and alcohol ignition interlock enforcement. Policies and programs cost money to implement, however, and state implementation budgets are limited. Consequently, decisionmakers need to prioritize and choose interventions that will reduce the greatest numbers of injuries and deaths for the implementation dollars available in their state.
Although there is much information on the effectiveness and costs of various interventions in places where interventions have already been implemented, little information is available about the potential effectiveness and costs for individual states.
A new interactive online tool, the Motor Vehicle Prioritizing Interventions and Cost Calculator for States (MV PICCS), enables policymakers to compare 14 traffic crash intervention policies and programs by effectiveness and implementation cost and by state. The free tool, created by the RAND Corporation with funding and technical support from the Centers for Disease Control and Prevention (CDC)'s National Center for Injury Prevention and Control and the Robert Wood Johnson Foundation, is available at the CDC website: www.cdc.gov/motorvehiclesafety/calculator.
This brief describes how policymakers can use MV PICCS to make cost-effective traffic safety policy decisions. It also describes the data and methods that inform the tool, including 14 effective traffic safety interventions and the cost-effectiveness analysis that compares the cost of implementation and the anticipated benefits.
MV PICCS has five capabilities that enable state policymakers to:
The Motor Vehicle Prioritizing Interventions and Cost Calculator for States considers 14 interventions. To focus on the interventions that can yield the largest benefit nationwide, MV PICCS considers interventions that have not yet been widely implemented across states. The selected interventions are also related specifically to driver and passenger behavior, can be implemented at the state or local level, and are proven to be highly effective. The tool does not account for every possible policy or program. These are the 14 selected:
Automated red light enforcement, more commonly called red-light cameras, is used to capture images of vehicles whose drivers fail to stop for red lights. Tickets are generally sent to offenders by mail.
Similarly, automated speed camera enforcement captures images of vehicles whose drivers are driving in excess of the posted speed limit. Unlike red-light cameras, which are deployed only at intersections, mobile speed cameras are often used to cover multiple road segments.
An alcohol interlock, also called an ignition interlock, is a device that prevents a vehicle from starting until the driver has blown into a tube and the device determines that the driver's blood alcohol concentration (BAC) is below the allowable level (0.02 in most jurisdictions). This intervention calls for interlocks to be installed on the vehicles of convicted repeat driving while intoxicated (DWI) offenders.
At a sobriety checkpoint, teams of police officers stop cars at a specific location to check drivers for alcohol levels. States generally publicize such events to discourage drivers from drinking, particularly during times when drunk driving is more common than usual (such as holiday weekends).
Saturation patrols consist of an increased police presence in selected locations, where officers patrol the area looking for suspicious driving behavior in an attempt to identify alcohol-impaired drivers. In contrast to sobriety checkpoints, police do not stop every vehicle.
Bicycle helmet laws mandate that children riding bicycles use helmets to reduce the likelihood of trauma to the head and its related consequences.
This law requires all motorcyclists, regardless of age or experience level, to wear a helmet that meets safety standards set by the U.S. Department of Transportation. These laws differ from partial helmet laws, which typically apply to only riders below a certain age.
States with seat belt laws vary in their enforcement. A primary-enforcement law allows police to ticket an offender exclusively for not wearing a seat belt. A secondary-enforcement law allows police to write someone a ticket for not wearing a seat belt only if the officer has pulled the driver over for a separate offense.
High-visibility enforcement is a technique that combines intense enforcement over a fixed period (for example, one or two weeks) with a publicity campaign. A campaign focused on restraint use generally includes all forms of restraints: seat belts, child safety seats, and booster seats.
This intervention requires a driver who has been convicted of DWI to surrender the vehicle's license plate, which is either impounded or destroyed. In some jurisdictions, the license plate is not physically removed; rather, the officer places a sticker on the license plate to indicate that it is invalid. The stickers are designed such that, if someone tries to remove them, they leave a visible pattern on the plate. Because it is relatively easy for police to observe that a vehicle is missing a license plate or the sticker, this intervention deters convicted DWI offenders from driving that vehicle.
Although all states have penalties for DWI, many states have additional programs that allow some offenders to be diverted out of the normal procedures or to plead guilty to a lesser offense and receive a lighter sanction. These programs more often target first-time offenders, with the goal of reducing the DWI caseload by diverting people who are thought to be unlikely to reoffend. Limits on diversion and plea agreements would increase the number of DWI arrestees convicted of more-serious DWI-related charges.
This intervention results in vehicles of DWI offenders being confiscated for a period of time and stored in a public impound lot. The offender can either reclaim or surrender the vehicle when the impoundment period ends.
This intervention requires all drivers over age 70 to renew their drivers' licenses in person at a department of motor vehicles, instead of using mail-in or online renewal.
This intervention adds $75 to a state's existing fine. This is a significant increase over existing seat belt fines in most states.
In MV PICCS, "effects" are the lives saved and injuries prevented by a policy or program. For each policy, estimates of the percentage reduction in those two aspects were developed based on previous research. For example, a review of motorcycle helmet studies found that motorcycle deaths declined almost 29 percent when states implemented mandatory helmet laws. The number of people killed in motorcycle crashes in each state was multiplied by 29 percent to estimate how many lives the law would save.
30% decrease in crashes involving those with previous DWI convictions
29% decrease in crash-related motorcyclist deaths
27% decrease in recidivism by those with previous DWI convictions
24% decrease in crashes involving those with previous DWI convictions
18% decrease in alcohol-related fatal crashes
17% decrease in deaths at intersections with signals
15% decrease in crash-related juvenile bicyclist deaths
12% decrease in speed-related crashes
11% decrease in recidivism by those with previous DWI convictions
9% decrease in fatal crash involvement rates for drivers ages 70+
8% (deaths), 20% (injuries) decrease in alcohol-related crash deaths and injuries
7% decrease in deaths involving vehicle occupants
7% decrease in fatalities involving vehicle occupants
5% decrease in deaths involving vehicle occupants
The tool estimates costs borne by the state (such as costs of police time and department of motor vehicle staff time). Some costs were scaled to each state based on wage rates. A "most common cost" was developed and used across all states. For example, the researchers looked at the actual per-camera costs for speed cameras in different cities. The costs of upfront items, such as passive alcohol sensors, were spread over five years. In some state-specific cases, assumptions needed to be developed.
The information on implementation costs and potential lives saved and injuries averted is used to create cost-effectiveness ratios for each intervention in each state. The cost-effectiveness ratio compares the effects and costs of implementing each intervention. Comparing the cost-effectiveness ratio for each intervention determines which policy would achieve the largest reduction in injuries and deaths for each dollar spent.
|State||The tool can analyze only one state at a time.|
|List of interventions to analyze||The user can investigate any combination of the 14 interventions.|
|Analysis type||The user must select one of two analysis types. The cost-effectiveness analysis looks at each policy separately, while the portfolio analysis takes overlapping policies into account.|
|Run type||The user can include as revenue the fines and fees that offenders pay to the state.|
|Budget||The user must tell the tool how much money is available to implement new policies.|
|Interventions to analyze||12|
|Analysis type||Cost-effectiveness analysis|
|Run type||Without fines|
|Interventions to analyze||12|
|Analysis type||Portfolio analysis|
|Run type||Without fines|
The data described above were used to program the tool. Users must tell the tool what to do by providing five pieces of information, as shown in Table 1.
We use Georgia here to demonstrate how the tool works. On the opening page, the user selects Georgia from the drop-down menu of states, chooses Basic Cost-Effectiveness Analysis from a radio-button list, and then clicks Submit. On the second page, the user would choose the interventions, run type, and budget. Table 2 shows these sample inputs.
As the MV PICCS screenshot in Figure 1 shows, Georgia can implement eight of 12 selected interventions with a $25 million budget. The selected interventions are highlighted in green, above the bold line. The total cost to implement these eight interventions is $19.8 million, which means the state is unable to fund any additional interventions with the remaining $5.2 million ($25 million – $19.8 million). The interventions shown in pink, below the bold line, are either not selected (bicycle helmet) or their cost exceeds $5.2 million.
This cost in dollars per year for this run type excludes any fines and fees paid by offenders, so the costs listed in Figure 1 are those that would be incurred by the state for implementation. Had we selected a run with fines included, some of these costs would be offset.
Implementing these eight interventions would result in 287 lives saved and 28,939 injuries averted.
Table 3 captures the inputs for Georgia, and the screenshot in Figure 2 shows how the tool treats interactions between interrelated policies and programs that make up a portfolio. Here, the type and cost of the 12 interventions are the same as in the basic cost-effectiveness example. These are shown in green. However, there is no cumulative cost or individual cost-effectiveness ratio, as in Figure 1. This is because the portfolio analysis assumes some interdependencies between interventions and thus does not assess them on an individual basis.
Because of the interdependencies between two of the seat belt-related interventions and two of the DWI-related interventions, fewer lives are saved and fewer injuries averted. This option provides a more realistic estimate of the overall effects. This makes MV PICCS a powerful tool for allowing decisionmakers to analyze many combinations of interventions in their states.
MV PICCS brings together, in one place, a wealth of information on the costs and effects of 14 traffic crash interventions. Users can change a variety of parameters: the state, the interventions to analyze, the type of analysis (looking at each intervention individually or using "portfolio analysis" to account for related interventions), the use of fines and fees to offset costs, and the budget. A built-in sensitivity analysis tool allows changes to the percentage reduction in injuries and deaths, the estimated monetary value of saving a life, and the total cost per intervention.
This report is part of the RAND Corporation Research brief series. RAND research briefs present policy-oriented summaries of individual published, peer-reviewed documents or of a body of published work.
This document and trademark(s) contained herein are protected by law. This representation of RAND intellectual property is provided for noncommercial use only. Unauthorized posting of this publication online is prohibited; linking directly to this product page is encouraged. Permission is required from RAND to reproduce, or reuse in another form, any of its research documents for commercial purposes. For information on reprint and reuse permissions, please visit www.rand.org/pubs/permissions.
The RAND Corporation is a nonprofit institution that helps improve policy and decisionmaking through research and analysis. RAND's publications do not necessarily reflect the opinions of its research clients and sponsors.