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Federal Highway Administration Research and Technology
Coordinating, Developing, and Delivering Highway Transportation Innovations
This magazine is an archived publication and may contain dated technical, contact, and link information.
|Publication Number: FHWA-HRT-05-003 Date: January/February 2005|
Publication Number: FHWA-HRT-05-003
Issue No: Vol. 66 No. 4
Date: January/February 2005
A county in California recently showcased a low-cost and successful program for saving lives on secondary roads.
|More crashes occur on rural roads, like this one through Potter Valley in eastern Mendocino County, CA, than on any other roadways in the Nation. Photo: MCDOT.|
According to the National Highway Traffic Safety Administration, rural roads—though often scenic—are actually the most dangerous roads in the Nation. In 2001, rural roads accounted for approximately 60 percent of all fatal crashes.
Many small secondary roads were constructed originally to follow property lines, so the curves often are not up to code in terms of the degree of turn. Some secondary roads on these old systems have no shoulders, no centerline stripes, and no road edge markings. Some have curves that start with one radius and end with another. Given these conditions, plus local economic realities that limit reconstruction to change alignments, correctly placed and consistently employed signs may be the most effective strategy to save lives at a cost that almost any county can afford.
Mendocino County, CA, has demonstrated just how effective signs are as a low-cost safety measure. In a landmark, low-tech program, the Mendocino County Department of Transportation (MCDOT) reduced its crashes by a startling 42.1 percent from 1992 to 1998 at a cost of $79,260 over the 6-year period. The benefit-cost ratio works out to $299 in savings for every $1 spent, using California Department of Transportation (Caltrans) formulas.
"Although this cost-benefit ratio may not be achievable on all projects, even a tenth of the cost-benefit ratio may justify the investment," says Federal Highway Administration's (FHWA) Road Departure Team Leader Harry W. Taylor.
MCDOT refers to its program for evaluating and improving the safety of the county's road signs as Road System Traffic Safety Reviews. The scope is similar to road safety audits and the evaluation process used by many State DOTs, but the focus is primarily on highway signs.
"We believe that the most cost-effective method for enhancing safety on rural roads is to make the driver more aware of road conditions through consistent signing and markings," says Eugene C. Calvert, P.E., former director of transportation with MCDOT and now principal project manager for the Collier County Transportation Services Division in Florida.
Mendocino County is similar to many rural counties, parishes, townships, and reservations across the Nation. Located about 161 kilometers (100 miles) north of San Francisco, Mendocino has a largely agricultural economy and a slowly growing population approaching 90,000 people. The terrain is mountainous, and many of the county's crashes involve vehicles running off the roads at curves.
|Mendocino County has miles of rural roads in the valleys and along the coast. This scenic road curves around Mendocino Bay with the town of Mendocino in the background.|
In size, the county is 9,091 square kilometers (3,510 square miles), and MCDOT is responsible for maintaining and improving 1,639 kilometers (1,018 miles) of secondary roads. Among them are paved and unpaved local roads, major and minor collectors, and one four-lane arterial carrying about 18,000 cars per day. Some of the local roads see an average daily traffic (ADT) of only 20 cars per day. Most of the collectors and paved local roads carry more than 500 ADT.
|North State Street in Ukiah, the county seat and center of population, is the only four-lane arterial in Mendocino County, carrying 18,000 vehicles in average daily traffic.|
The county transportation agency operates with limited funds and has to maximize the use of every highway dollar. "The local government highway agencies that are responsible for the majority of the two-lane roads in the United States do not typically have large resources or the professional staff to complete exhaustive safety studies," says Calvert. "They need to get the most bang for their buck for any safety improvements that are implemented."
Mendocino County focused on improving signage because installing signs is cheaper than improving the road geometry by widening or flattening curves. Installation of each sign costs Mendocino County about $107 for labor and materials. Quite a few signs can be installed for an amount that would pay for very little in construction realignment.
Sign Color Studies
FHWA has had sign programs over the decades, and sign technology has changed and is continually evolving. For example, FHWA has extended the regulations for sign retroflectivity to all signs, not just regulatory and warning signs, to improve safety and visibility during adverse ambient conditions. Other changes are afoot as well.
In 1998 and 2001, Vicki Neale, director of the Center for Human Factors Research at the Virginia Tech Transportation Institute (VTTI), conducted research that led to adoption of black text on fluorescent pink (originally an orangish coral) backgrounds for signs targeted at incident management. Such signs might include notification of a temporary exit closure or detour, as described in Section 6-1 of the current Manual on Uniform Traffic Control Devices (MUTCD). See http://mutcd.fhwa.dot.gov/pdfs/2003r1/Ch6I.pdf.
The studies, funded by the Virginia Transportation Research Council (VTRC), first evaluated existing reserved MUTCD traffic sign colors that had not yet been assigned for a specific use. Shortly thereafter, VTTI and VTRC determined that additional research was warranted on the fluorescent counterparts of those colors. The 2001 study compared black on fluorescent pink, fluorescent yellow on fluorescent purple, black on fluorescent yellow-green, and nonfluorescent yellow on nonfluorescent purple.
Overall results indicated that black on fluorescent yellow-green was the most visible color, but this combination was already reserved by FHWA for pedestrian crosswalk and school zone signs. "The next best performer," says Carl K. Andersen, manager of FHWA's Arens Photometric and Visibility Laboratory at the Turner-Fairbank Highway Research Center in McLean, VA, "was black on fluorescent pink-thus the selection of this highly visible color combination for these critical signs."
For more information, contact Carl K. Andersen at 202-493-3366 or email@example.com.
"One of the most impressive things about the program is its practicality," says Susanna Hughes-Reck, a technology deployment specialist with the FHWA Resource Center in Denver, CO. "Almost any county can replicate Mendocino's strategy as long as the program is adapted to local conditions."
In the late 1980s, long before safety became a priority for local agencies, Mendocino County recognized that something needed to be done. Selecting a handful of roads, the agency looked at the previous year's collision records for each road. At that point, the county was choosing the roads by a trial-and-error method in which the roads reviewed were the hotspots that had the greatest number of crashes.
Then in 1992, Mendocino named Stephen Ford, a civil engineer, as the county's traffic engineer, although he had no background in that field at the time. What he found surprised him. "When I first started," says Ford, "I saw that our previous traffic engineers had been submitting reports, but no signing changes had been made. I also realized that we had been reviewing the same few roads over and over again."
He decided to do the reviews in a systematic way instead of spot checks. So he divided the county into three major geographical areas—the coast, southern inland, and northern inland—and then instituted a rotation system, so that each road would be reviewed on a recurring 3-year cycle to identify signing and marking deficiencies.
|The 2003 edition of FHWA's Manual on Uniform Traffic Control Devices. The MUTCD served as Mendocino County's guidebook for selecting and placing signs.|
Starting small, Ford reviewed 25 miles of road in 1992, covering the engineering costs with $7,200 secured from the Regional Transportation Planning Agency using Statewide Transportation Improvement Program (STIP) funds. Every year after that, the county expanded the program, until 226 miles of road were reviewed in 1998 at a cost of $10,500.
For each review, the reviewer studies all of the crashes reported in the subject area during the preceding 3 years. This review requires reading each individual collision report, not just statistical summaries, to understand what the investigating officer saw and why the crash may have occurred at that particular location. Early efforts concentrated on improving curve and turn signing and on eliminating nonstandard signing. Later efforts focused on object markers for bridges, culverts, roadside trees, and other hazards, plus the installation of delineators to outline curves, a measure that is particularly useful for motorists driving at night or during inclement weather.
Reviewing in 3-year cycles tends to even out the erratic annual variations in collision numbers common on low-volume or rural roads. The cycles allow some regression to the mean and improve the reviewer's chances of spotting truly meaningful trends in collision patterns. Cyclical reviews allow the message, location, or physical dimensions of the sign installations to evolve in response to experience. In addition, maintenance crews tend to focus on potholes and ditches, failing to notice that a sign may have been damaged or fallen down. The ongoing reviews ensure that conditions do not deteriorate and that the crash rates do not rise again. Also, after the first couple of reviews, situations requiring attention beyond just signing and marking improvements become apparent. Information developed for Traffic Safety Reviews lends support to requests for project funding of safety improvements such as turn lanes and removal of obstacles.
The review program is affordable and low-tech. The only essential equipment is a vehicle equipped with an accurate distance measuring instrument and a ball bank indicator to locate and evaluate crash sites. An accurate milepost system is desirable, though not necessary, as are a computerized sign inventory, collision databases, and a laptop computer. In 1992 MCDOT had only a computerized sign inventory. A laptop computer, which increased productivity significantly, was acquired a couple of years later. The county is just now obtaining a geographic information system (GIS)-compatible collision database and is still working on installing an accurate milepost system.
Funding from the Hazard Elimination Safety (HES) Program paid for Mendocino County's sign installations in 1992. Much of the county's sign inventory was old, so about one-quarter of the signs were changed that first year. "After that," says Ford, "we included something in the budget so that signs would get replaced within a few months after each review."
To provide guidance in selecting potential corrective measures and to ensure standardization of signing, the county used the policies in the Caltrans Traffic Manual. This was superseded in 2004 when California adopted the FHWA MUTCD. Ford believes that the rational placement of standard signs is critical to the program's success.
In June 2003, Ford and Calvert presented a technical paper on Mendocino County's program at the Transportation Review Board's 8th International Conference on Low-Volume Roads. In that paper, they noted amazingly successful results on the original 19 roads in the program for the period from 1992 to 1998: Total crashes had declined from 601 to 348, or 42.1 percent. Fatalities were down from 13 to 5, and injuries had decreased from 266 to 155.
Unfortunately, Ford is not aware of any other counties or States that have developed a signage program similar to Mendocino's. "Every time I take a driving trip around the country," says Ford, "I see a lot of nonstandard signing out there on small roads in rural areas, where people are in the same boat we are—not a lot of money and a small staff."
Mendocino County has many scenic byways, such as this postcardworthy coastal road near the Point Arena lighthouse (left), a Comptche Ukiah Road passing through young redwoods (above), and a rustic road in the village of Comptche (below). Photos: Stephen Ford, MCDOT.
When Calvert joined the county as director of transportation, he asked Ford to research the benefits of the program and to calculate the cost-benefit ratio. Ford totaled up the costs, finding that the engineering reviews in 1992 and 1995 added up to $14,760. Sign replacement in 1992 cost $46,300 and $18,200 in 1995. The program's grand total was $79,260.
He then compared crash records for two sets of control roads: the county roads that had not yet been reviewed and the State highways within the county, also not reviewed. In most cases, both sets of control roads had the same characteristics as the reviewed roads: the same driver demographics, same driving habits and patterns, same crash reporting and investigation standards, same weather and climatic conditions, and same funding levels and maintenance practices.
The unreviewed county roads showed a 26.5-percent increase in total crashes over the 6-year period. Without the program, if crashes on the reviewed roads had increased at the same rate, the county would have had 696 additional crashes.
|During the showcase's field visits, Mendocino County closed off the road except for local traffic and stationed flaggers at both ends. Note the small "2" and "5" signs attached to the curve signs. Number 2 (the sign farthest from the camera) represents the signing condition as of 1992. Number 5 (the sign closest to the camera) represents the 1995 upgrade.|
Therefore, using Caltrans' 1998 estimate of $34,100 for the average total cost of a crash on rural two-lane mountainous roads (emergency response, medical costs, time lost from work, and the like), Ford determined that this would have resulted in a greater number of additional crashes (696) and a savings of $23.7 million, a cost-benefit ratio of 1/299. The State highways did show a 3.3-percent decrease in crashes, perhaps due to the State's history of standardized signing and marking. Still, even at that rate of decrease, the county would have had 369 additional crashes. Using the Caltrans estimate, this would have resulted in a savings fo $12.5 million, or $159 saved for every $1 spent.
In either case, the benefits are above normal. Although all projects may not have the same cost-benefit ratio, the ratio does indicate a large benefit for this specific project.
To highlight Mendocino's strategy for reducing crash rates on rural roads, FHWA's Local Technical Assistance Program (LTAP) sponsored a showcase on September 28–29, 2004. The event was part of a series of LTAP showcases for local highway agencies featuring hands-on demonstrations of proven, new technologies and practices.
Nationwide, rural transportation agencies are responsible for constructing and maintaining nearly 4.8 million kilometers (3 million miles) of roadways and more than 29,000 bridges. But at the local level, technology buy-in is complicated by the financial, professional, and political risks that public agencies face when committing limited funding to the implementation of technologies with which they themselves have not had field experience. In the 1980s, FHWA introduced LTAP to facilitate information exchange to support local road and bridge agencies. In 1995, the LTAP center in Florida launched an innovative Product Demonstration Showcase program with the goal of speeding up the implementation of new technologies at the local level.
Showcases target decisionmakers such as crew chiefs, road supervisors, city and county engineers, public works directors, and elected officials. Travel stipends help participants cover the cost of attending. After the showcase, based on their newly acquired experience with a technology, local personnel have more confidence about putting their professional reputations on the line when they go to their city commissioners and say, "We've got to have this technology." (For more on the showcase program, see "Technology Goes Local" in PUBLIC ROADS, March/April 2003.)
|Ben Colucci, codirector of the Puerto Rico LTAP, inspects a sign that was placed temporarily during the showcase to illustrate a former signing condition.|
The 188 participants in the Mendocino showcase attended presentations by county and LTAP staff on the importance of highway safety, the collection of data to evaluate safety problems, the causes of crashes and what to look for in crash hotspots, and the importance of consistent signage and how to establish safe and consistent advisory speeds on curves. The participants gained a basic understanding of the MUTCD, including various types of signs, such as regulatory stop signs, warnings for curves, guide signs for route numbers, service signs, and markers for recreational and cultural attractions.
They also visited field sites to observe roadway conditions and the corrective measures that Mendocino County had applied. The participants discussed whether the right signs were used in the right places or should be relocated, whether the signs were large enough, where the road should have object markers (bridge abutments, culverts, roadside trees) and curve delineators, whether the road had enough signs or too many, whether advance warning signs and street signs were adequate, and whether the posted advisory speed limits at curves were consistent from one location to another. They were driven to the sites where actual crashes occurred and asked to consider why crashes happened in given locations by looking at damaged guardrails, skid marks, and the like.
During the site visits and question-and-answer sessions, the showcase participants raised a number of issues. They pointed out, for example, that most of their agencies—like the MCDOT itself—have neither the technical staff nor the financial resources to develop crash analysis and asset management systems. Jurisdictions without engineers on staff were advised that they can seek engineering assistance from their State DOT, a nearby city, or a traffic engineering consultant.
To further respond to these technical needs, representatives from the Michigan LTAP center presented a crash analysis and reporting system that is integrated with agencies' management systems for road surfaces, signs, guardrails, and pavement markings. Showcase participants received handouts on the Michigan crash analysis system plus free copies of software packages for sign and asset management developed by the New Hampshire and Utah LTAP centers. The software packages are user-friendly, even for a relative computer novice, especially since postshowcase technical support is available to assist participants with implementation of their own sign programs. (See "Software Assistance".)
Three special presentations during the Mendocino event showcased software applications that can help local agencies develop their sign review programs.
Local Agency Crash Analysis Using RoadSoft GIS: Over the past 11 years, the Michigan LTAP, with support from the Michigan DOT and FHWA, developed RoadSoft GIS as a transportation management tool for local agencies in Michigan. RoadSoft GIS is an integrated roadway management system designed specifically for counties and cities. It enables agencies to manage their roadways and roadside assets (signs, pavement markings, guardrails, culverts, pavements, and crash data) within one GIS-based software application.
Sign Inventory Management System (SIMS): Charlie Goodspeed, professor in the College of Engineering at the University of New Hampshire, demonstrated SIMS, which provides effective sign management in an easy-to-understand format with easy-to-use software. Initially designed for small- to medium-sized county highway agencies, SIMS has helped large agencies provide adequate signing as well. It enables local agencies to identify unsafe traffic signs, repair or replace them, and to remove obstructions.
The New Hampshire LTAP developed SIMS with three guiding principles. First, the most important responsibility of a government entity that maintains roads is to ensure that motorists can travel on its roadways safely. Second, effective management of traffic signs is essential to ensure motorist safety. Finally, effective maintenance is the best defense against civil liability claims involving traffic signs.
The management system and its supporting software contain the following components to help highway agencies manage their traffic signs effectively: sign inventory including condition assessment, priority analysis of the most serious threats to motorist safety, scheduling of repairs and maintenance, documentation of actions through SIMS work orders to facilitate the preparation of sign maintenance budgets, and parts management.
With the SIMS software, users can organize and access the data by index, query software tools, and generate customized reports. The New Hampshire LTAP and similar centers in certain other States provide technical support.
Transportation Asset Management Software (Utah LTAP TAMS): Doyt Bolling, director of the Utah LTAP Center, has developed an asset management package that helps cities and towns implement a GIS-based system enabling local agencies to assess their total needs, develop appropriate preservation programs, and evaluate and predict the likely outcomes for the transportation system in terms of service life for a period of up to 10 years. Stuart Thompson, assistant director with the Utah LTAP, demonstrated the sign management module added by the Utah LTAP to TAMS.
To address the need for financial resources, the showcase included two grants resource specialists who discussed potential grant sources, such as the HES Sign Replacement Programs, State safety programs, governors' offices of traffic safety, regional rural transportation planning agencies, and metropolitan planning organizations. Participants asked so many questions of the grants specialists that their sessions had to be extended.
Some equipment is needed to get started: a distance measuring instrument that attaches to the dashboard of a vehicle and has a digital readout, an inclinometer or hand level for measuring down grades, a ball bank indicator for measuring curves, safety vests, flashing beacons, an audio recorder, and a laptop (optional). Crash reports can be logged on a computer or in a binder, recording the date, road, and milepost location. A computerized and searchable crash database will help with identifying trends and patterns, as well as analyzing the effects of the program. Most States require a mileage inventory for arterials and collectors, so that inventory can be a viable place to start a safety review program.
Typical fields on a sign inventory database include the road number and name, installation number, milepost, side of road, facing direction, size, face material, MUTCD sign code, mounting type, installation date, and maintenance date.
"You can start small," says Calvert. "You don't have to do every road the first year. Start with one or two, find out what works for you, and slowly add more roads to the system." A given county's schedule of reviews will depend on the personnel and time available, geographic extent, and number of road miles.
|A ball bank indicator and distance measuring instrument are mounted on a car dash in the line of sight.|
Further, in cooperation with the Idaho Technology Transfer (T2) Center, FHWA has funded the development of a short course on sign safety reviews, and the course is available on CD-ROM. "A road superintendent with proper training through the course can make a difference at the local level," says Calvert. "He may not be able to make a 42-percent difference, but every little bit helps."
Finally, representatives of the National LTAP Association's Product Demonstration Program at the Florida LTAP Center will contact all participants over the coming year to track local implementation of sign review programs throughout the United States and to document the success of those programs. "We want to ensure that we weren't just a fluke," says Calvert. "Maybe our signs were so bad that we got big results. Right now, we don't have the statistics."
He adds that if Mendocino County's results prove to be typical, then ensuring that safety program funds get to local agencies could "really make a dent in fatalities. Like many throughout the United States," says Calvert, "I too have had family and friends die on our Nation's rural highway system. If we can save a life, this effort will be worth it."
Road Safety Audits
A road safety audit is a formal safety performance examination of an existing or future road or intersection by an independent team. The American Association of State Highway and Transportation Officials' Technology Implementation Group (TIG) recently approved road safety audits as a focus technology. In partnership with TIG, FHWA included road safety audits on its list of priority technologies and innovations. Visit www.fhwa.dot.gov/crt/index.cfm.
Gib Peaslee is codirector of the Florida T2 Center and director of the Florida LTAP. He has been involved in the development of the Product Demonstration Showcase program, a national LTAP initiative to encourage implementation of field-tested new products and processes among local, State, and Federal road and bridge professionals.
For more information on the Mendocino County program, contact Eugene Calvert at 239–213–5833 or EugeneCalvert@colliergov.net, and Stephen Ford, RCE, at 707–463–4351 or firstname.lastname@example.org. For information on the short course, contact Jim Smith, 352–392–2371, ext. 270, or email@example.com to request the training. To learn more about the showcase program, visit www.pdshowcase.org or contact Gib Peaslee at 352–392–2371, ext. 245, firstname.lastname@example.org.