Text Size:   A+ A- A   •   Text Only
Find     
Site Image

Abstract XXIV

Teen Licensing

Effectiveness of Oregon's Teen Licensing Program

Significant changes in Oregon’s teen licensing laws went into effect on March 1, 2000.  The new laws expanded the provisional driving license program which had been in effect since October 1989 and established a graduated driver licensing (GDL) program for all drivers under age 18.  The program is intended to reduce fatal and injury crashes among teen drivers and to promote safe driving.
 
Two studies were completed by research organizations that were designed to assess the impact of Oregon’s teen licensing laws.  The National Highway Traffic Safety Administration (NHTSA) published a study, Evaluation of Oregon’s Graduated Driver Licensing Program, conducted by the Center for Applied Research, Inc. (CAR).  The American Automobile Association financed a study, Reducing the Crash Risk for Young Drivers, which was conducted by the Traffic Research Injury Research Foundation (TIRF) to review not only Oregon’s graduated licensing program but also programs in Ontario and British Columbia, Canada.   Analysis of driver records as well as surveys and focus group research were included in these studies.

The Oregon Department of Transportation (ODOT) has synthesized the results of these studies.  This report provides background information, summarizes the key findings of the two reports and presents conclusions and recommendations based on the results. The results indicate that Oregon’s graduated driver license program has safety benefits and it should be continued.


Back to Top

MSE Retaining Walls

Evaluation of Corrosion of Metallic Reinforcements and Connections in MSE Retaining Walls

Mechanically Stabilized Earth (MSE) retaining walls have become the dominant retained wall system on ODOT projects. The permanent MSE walls constructed on ODOT projects, in recent years, use metallic reinforcements and facing connections buried directly in the backfill soil. Accelerated deterioration of these structural elements would have serious financial and safety impacts for the Department.

Classical MSE wall design incorporates an estimate of deterioration of reinforcement by corrosion. Monitoring of actual corrosion performance, however, is an important element of managing the current inventory of MSE walls. Monitoring could answer key questions that can provide for the best management of the existing walls, and provide feedback to the design process for future installations.

This report details a literature review of methods for estimating and measuring deterioration of structural reinforcing elements in both concrete and MSE walls. It also presents a selected history of metallic reinforcement design specification and utilization. A listing of the MSE walls that can be identified in the ODOT Bridge Data System is included.


Back to Top

Concrete Barrier

Concrete Barrier Distress in La Grande, Oregon
 
Several precast concrete barriers in eastern Oregon were noted to be deteriorating at an advanced rate. The ODOT Research Unit took several core samples from the barriers and conducted analyses. Petrographic evaluations determined that the strongest link between barrier deterioration and any one factor was the amount of entrained air. In general, older, poor-quality concrete, which was continually exposed to freeze-thaw events, exhibited advanced signs of distress.


Back to Top

Older Driver in Oregon

The Older Driver in Oregon: A Survey of Driving Behavior and Cessation

Although there are several instances where older drivers have had their licenses taken away, no state-wide study of either the reasons for driving cessation or the need for transportation after driving cessation have been conducted. Using a sample of Oregon drivers and former drivers this project completed surveys by mail, and phone. Questions focused on the factors influencing driving cessation, physical and emotional barriers delaying driving cessation, modes of alternative transportation, and warning signs that caused a driver to stop driving.
 
The study found that changes in driving patterns, occurred gradually and late, mostly for respondents in their late 70’s or early 80’s. Those most likely to have chosen to stop driving were older, depressed females in poorer health who were living in senior housing, using alternative transportation when available, making fewer trips, and seeing fewer limitations associated with using alternative transportation. Relocation to improve access to transportation alternatives was not seen by most respondents as a viable option. These and other findings are thoroughly discussed in this report.



Back to Top

Advisory Curve Speeds

Methodologies for Estimating Advisory Curve Speeds on Oregon Highways 

This report reviews an Oregon research effort to evaluate the identification and marking of advisory speeds on Oregon highways. In particular, this research effort focused on the implications of modified advisory speed thresholds and identification procedures following the most recent and the upcoming MUTCD and the Traffic Control Devices (TCD) Handbook recommendations. The primary objectives of this research effort were to help identify the basis for the current and proposed advisory speed posting procedures (with specific attention to the horizontal curve location on rural roads and passenger vehicle condition), to evaluate Oregon placement strategies at a variety of locations, and to identify potential criteria for establishing advisory speeds for these curved sections on Oregon highways. Included with this evaluation is an assessment of associated costs for implementation of a modified advisory speed policy in Oregon. Through the use of both manual and digital ball-bank devices, the report identifies compliance of current and future advisory speed thresholds for both State- and county-maintained roads, expected costs for upgrading State-maintained facilities, evaluation of alternative computational methods, and an assessment of the differences observed between the two different ball-bank devices.


Back to Top

Solar-Powered Markers

Evaluation of Solar-Powered Raised Pavement Markers
 
An evaluation of a limited number of solar-powered raised pavement markers (SRPMs) was conducted to determine if this type of marker would be more visible than retroreflective markers in some situations on Oregon highways. SRPMs typically use Light Emitting Diodes (LEDs) that are powered by solar cells. Some markers have retroreflective surfaces as well. The Oregon Department of Transportation, Research Unit, performed preliminary tests which included environmental tests (extreme temperatures, immersion), optical performance tests, and observation tests. Selected markers were sent to the Federal Highway Administration's Photometric and Visibility Laboratory (PVL) at the Turner-Fairbank Highway Research Center in McLean, Virginia for additional evaluation. A series of tests was performed to measure both the LED signal and the retroreflected light. It was found that each type of marker had significant shortcomings, so the project was terminated prior to field trials being performed.


Back to Top

Rainfall Analysis

Mapping of Rainfall Analysis for Oregon 

 For this study regional frequency analyses were conducted for precipitation annual maxima in the state of Oregon for the 24-hour duration. A total of 693 precipitation gages in Oregon, southern Washington, western Idaho, northern California and northern Nevada were included in the study, representing 34,062 station-years of record. A regional analysis methodology was utilized that pooled data from climatologically similar areas to increase the dataset and improve the reliability of precipitation-frequency estimates. The regional analysis methodology included L-moment statistics, and an index-flood type approach for scaling the annual maxima data. L-moment statistics were used to: characterize the variability, skewness and kurtosis of the data; measure heterogeneity in proposed homogeneous sub-regions; and assist in identification of an appropriate regional probability distribution.

Spatial mapping techniques were employed for mapping of the precipitation-frequency information. This included spatial mapping of at-site means, L-moment ratio values of L-Cv and L-Skewness, and mapping of precipitation for selected recurrence intervals. Procedures were employed to minimize differences between mapped values and observed station values in a manner that was consistent with the regional behavior of the data and also recognized uncertainties due to natural sampling variability.

Color-shaded isopluvial maps were developed for the 6-month, 2-year, 10-year, 25-year, 50-year, 100-year, 500-year, and 1000-year precipitation recurrence intervals. Electronic gridded datasets are available for use in creation of GIS applications that utilize precipitation-frequency information.
 
A catalog of extreme storms was assembled that lists precipitation events that exceeded a 20-year return period for the various climatic regions. The information from the storm catalog was also used to conduct seasonality analyses identified the occurrence frequency of extreme storms by month. In particular, the seasonality analyses identified those months that were the most likely and least likely for an extreme event to occur.  This information is useful in rainfall-runoff modeling and can be used in conducting hydrologic analyses throughout the Oregon study area.


Back to Top

Weigh-in-Motion Data

Development of Truck Axle Spectra From Oregon Weigh-in-Motion Data for Use in Pavement Design and Analysis
 
Four weigh-in-motion (WIM) sites in Oregon, representing high, moderate, and low average daily truck traffic (ADTT) volumes, were selected to characterize axle weight and spacing spectra on Oregon state highways. Seasonal variations were considered by investigating data occurring over the four seasons: winter, spring, summer, and fall. WIM data were cleaned and filtered, and analyzed. Axle data, including group and individual axle weights as well as axle spacings, were evaluated. Hourly truck volumes were also examined. Results were summarized and statistics were developed for the characteristic data. The characterized Oregon WIM axle data were incorporated into the Mechanistic Empirical Pavement Design Guide (MEPDG) software program to permit State and ADTT volume-specific axle weight spectra, average axle group spacing, and hourly volume data to be used in the pavement analysis/design. In order to implement the Oregon WIM data, a "virtual" truck classification was created in the MEPDG program. The Oregon-specific date that were required for input into the MEPDG were hourly truck volume distribution, site-specific axle weight data, average number of axles per truck, and average axle spacing. Implementation of the Oregon WIM data will improve the pavement design process in the State by designing to more realistic local loading conditions.



Back to Top

ODOT Project Delivery

Evaluation of Oregon Department of Transportation Project Delivery

This report summarized analysis of Oregon Department of Transportation (ODOT) methods of insourced and outsourced project delivery using the data obtained from ODOT reporting systems, ratings of project effectiveness by ODOT Area Managers and by construction contractors, and interviews with ODOT Area Managers and managers from engineering consulting firms that ODOT uses for outsourced design-bid-build projects. Results of a literature review and DOT survey were published in an interim report in December 2003. Guidelines, including a decision tree, are provided for assignment of projects for insourced design-bid-build, outsourced design-bid-build, or design-build delivery.



Back to Top

2007 Needs and Issues

2007 Transportation Needs and Issues Survey

The Transportation Needs and Issues Survey was conducted in October and November of 2006 by the Survey Research Center at Oregon State University. The survey used a random digit dialing telephone survey method and completed a total of 1,013 interviews. The random sample was stratified by ODOT Region and contained at least 200 completed interviews per region. The statewide data was weighted to reflect the different population sizes within each region, household non-response by region, the variable number of landlines within a household, the number of adults in the household, and population characteristics of gender, age, and race/ethnicity.


Back to T

Geosynthetic Materials

Geosynthetic Materials in Reflective Crack Prevention

Reflective cracking due to shrinkage and brittleness in asphalt pavements can seriously degrade an asphalt overlay before it is near the end of its design life.  Geosynthetics have been used to impede the reflection of existing transverse cracking to the new overlay.  The geosynthetics are intended to minimize the tension transferred to the overlay from the existing pavement.  The Oregon Department of Transportation (ODOT) installed a test section consisting of 98 transverse cracks treated with five different geosynthetic types, 22 transverse cracks treated with crack filling only and a control section of 20 untreated transverse cracks.
 
The test and control sections were monitored from 1999 to 2007.  Each of the 140 test sites were revisited once each year to determine if the cracks had reflected, and if they had, measure their length and width.  At the end of the study comparisons were made to determine if the geosynthetic materials were effective at controlling (by preventing or lessening the return of) reflective cracking.



Back to Top

Multi-Lane Roundabout

Adjustment of Driver Behavior to an Urban Multi-Lane Roundabout

In the summer of 2006, the city of Springfield, Oregon installed the first urban multi-lane roundabout in the state. It was hypothesized that after installation, speed variability on approaches to the intersection would decrease from the values with the previous signalized intersection. It was also hypothesized that the initially observed high incidence of driving errors associated with specific areas of the roundabout would decrease over time. Before and after speed recordings of approach roads to the intersection revealed a significant increase in mean speed, but no consistent change in speed variability. Some design features caused initial confusion amongst drivers negotiating the roundabout, but the number of observed incidences of confused behavior declined over the first six months of operation at a rate that fit a classic logarithmic learning curve. 



Back to Top

Driver Improvement Program

Evaluation of the Oregon DMV Driver Improvement Program

This report provides an evaluation of the Oregon Department of Transportation-Driver and Motor Vehicle (DMV) Services Driver Improvement Program (DIP), which was substantially changed in 2002.  Prior to 2002, the DIP was organized around four progressive steps involving advisory letters, warning letters, probation, and suspension.  The current program is organized around two steps: restriction and suspension.  The timeline to the steps in the current program have also been shortened.  To evaluate the current program, driver records of persons suspended between January and July of 2004 were examined in relation to a sample of Oregon’s driving population.  The incidence of crashes and traffic offense convictions of DIP subjects in the 18-month period prior to suspension was compared to the incidence of these events among the driving population.  A similar comparison was also made for the 18-month period following suspension.  A substantial reduction in the relative incidence of crashes and convictions among DIP subjects following suspension was observed.  This finding is subject to the effects of regression-to-the-mean.  An approximation of regression-to-the-mean effects was made based on prior evaluations of Oregon’s DIP that employed a true experimental design.  A regression analysis was also undertaken using driver record information from the period prior to suspension to estimate the likelihood of post-suspension crash and traffic offense conviction involvement.  The estimated likelihood of post-suspension crash involvement was significantly affected by the frequency of pre-suspension crashes, but not by the frequency of pre-suspension convictions.  Conversely, the estimated likelihood of post-suspension convictions was significantly affected by the frequency of pre-suspension convictions, but not by the frequency of pre-suspension crashes.  Two changes in the DIP are suggested in the concluding section of the report.  The first change involves re-instituting warning letters, given their demonstrated cost effectiveness in the driver improvement literature.  The second change involves the assignment of greater weight to crashes in triggering license actions, based on the regression findings.




Back to Top

Incentive/Disincentive

Establishing Guidelines for Incentive/Disincentive Contracting at ODOT

This report describes the results of a research project which explored the use of Incentive / Disincentive (I/D) contracting at the Oregon Department of Transportation (ODOT).  The research found that I/D contracting is a relatively rare practice within ODOT.  When I/D contracting occurs, the special provisions and parameters (such as setting incentive amounts) are managed on a centralized basis by a small group of individuals.  These individuals have used engineering judgment to develop these provisions and parameters in an environment of little historical data.  Most of the knowledge of I/D contracting resides with these individuals, and there is little summarized written information that others could use to also develop similar provisions and parameters.  Nationally, there is a wide mix in the use of I/D contracting amongst the various departments of transportation (DOTs).  FHWA and NCHRP have published reports that compile these experiences and provide recommendations for I/D contracting.  This work at the federal level is the basis for the development of an ODOT methodology for identifying project conditions that could lead to the use of I/D contracts.  ODOT’s Office of Project Delivery uses Operational Notices to document and disseminate operational procedures.  A draft I/D Operational Notice is included in this report as a potential tool for implementation of the findings.
 
Significant in I/D contracting is the establishment of the amount of the incentive (and disincentive).  Previously published articles recommend that the incentive be set more than the “lower boundary” of contractor’s cost of the acceleration (plus a reasonable profit), but less than the “upper boundary” of the cost of the delay to the public.  This latter “upper boundary” value is usually established through the calculation of Road User Costs (RUCs), which calculation is commonly performed by DOTs, including ODOT.  The research discovered, however, that there is a lack of working-level techniques to establish the “lower boundary” of the contractor’s cost of acceleration plus reasonable profit.  This research proposes a method of economic analysis in determining the contractor’s costs for acceleration.  A model is developed that establishes the “lower boundary” and “upper boundary” parameters based on evaluations of contractors’ costs and Road User Cost (RUC) cost techniques.  These boundaries in turn provide a range within which incentive amounts would be effective.  While the model is demonstrated in Microsoft Excel, the calculation methodology could be performed on a standard form, calculator or a different spread sheet program.  The standardization of the process through defined methods and/or program templates provides a formal method and basis for determining effective values for incentives – leading to consistency and auditability.


Back to Top

Environmental Streamline

Innovation in Environmental Streamlining and Project Delivery: The Oregon State Bridge Delivery Program
 
Surface transportation planning in the United States has become a complex system of intergovernmental planning and environmental compliance requirements over the past several decades. As a result, the process from planning stage to project implementation has become significantly lengthier with associated delays and cost increases. The field of in-depth case studies that might serve as templates to help agencies at various governmental levels develop effective environmental streamlining efforts is still relatively small.  What are some of the critical elements of successful environmental streamlining? What individual, organizational and institutional features influence the development and implementation of such programs? A case study of the Oregon Department of Transportation’s Bridge Delivery Program follows how one such effort went from idea to program and provides insights into factors that helped create an environmental streamlining program. The study should be of interest to practitioners, policy makers and academics.


Back to Top

2004 TOP Survey

2004 Traveler Opinion and Perception Survey

In November 2004 the Federal Highway Administration conducted the Traveler Opinion & Perception Survey (TOPS).  This was a nationwide survey with the objective of understanding the needs and expectations of users of the nation’s transportation system.  To gain a better understanding of Oregonians’ attitudes about the transportation system, the Oregon Department of Transportation (ODOT) funded additional interviews and expanded the survey to cover additional issues.  This summary report presents findings of the Oregon survey, compared with results from the Pacific states and the nation as a whole.  The report covers opinions on the following issues:
•    What contributes to an effective and high quality transportation system;
•    Satisfaction with the transportation system;
•    Delays resulting from roadwork;
•    Work zone management;
•    Bridge conditions;
•    Support for future transportation programs; and
•    Environmental concerns.


Back to Top

Water Facility Investigation

Water Quality Facility Investigation

The genesis for this research project was a desire to comply with the National Pollutant Discharge Elimination System (NPDES) as cost effectively as possible.  The construction of stormwater handling and treatment facilities is costly because of the labor, materials and land required.  After these facilities have been built, they then present an ongoing maintenance liability.  In addition, the provisions of NPDES call for monitoring that presents another ongoing cost.  Research in all these areas could lead to improved water quality, reduced costs, or accomplishing both simultaneously.  This project evaluated the state of practice and available data regarding stormwater Best Management Practices (BMPs) and monitoring, devised a streamlined and simplified approach to try and satisfy monitoring requirements, and then attempted to use that approach to evaluate both traditional and innovative stormwater BMPs.  These attempts identified obstacles to systematically and cost effectively monitoring stormwater BMPs and possible remedies to these obstacles.  The key outcomes of the project were the validation of a novel BMP, the identification of obstacles to monitoring, and a template for developing BMP monitoring plans.


Back to Top

Water Quality Facility

Water Quality Facility Investigation - Summary Report
The genesis for this research project was a desire to comply with the National Pollutant Discharge Elimination System (NPDES) as cost effectively as possible. The construction of stormwater handling and treatment facilities is costly because of the labor, materials and land required. After these facilities have been built, they then present an ongoing maintenance liability. In addition, the provisions of NPDES call for monitoring that presents another ongoing cost. Research in all these areas could lead to improved water quality, reduced costs, or accomplishing both simultaneously. This project evaluated the state of practice and available data regarding stormwater Best Management Practices (BMPs) and monitoring, devised a streamlined and simplified approach to try and satisfy monitoring requirements, and then attempted to use that approach to evaluate both traditional and innovative stormwater BMPs. These attempts identified obstacles to systematically and cost effectively monitoring stormwater BMPs and possible remedies to these obstacles. The key outcomes of the project were the validation of a novel BMP, the identification of obstacles to monitoring, and a template for developing BMP monitoring plans.


Back to Top
​​