This paper describes how human factors (HF) and user workload (WL) can be used by highway designers and traffic engineers to quantify the potential safety of sections of highway. Users’ WL is a ...quantitative measure of HF. Both HF and WL are used successfully in other fields, such as aviation when pilots have difficulty in using instruments and in touch-down before the start or end of the runway. The traditional highway approach of gauging success is by counting crashes. But with fatalities exceeding 30,000 a year for more than 20 years, the time is right for a new method of analysis. The author has integrated specific WL metrics into a simplified example to aid designers, traffic engineers, and safety analysts in assessing user problems before building new projects or road upgrades. The example uses static and dynamic WL and alternating renewal (AR) metrics (not used by others) to quantify user WL in highway segments for the purpose of illustrating the variation of design and operational safety conditions. The example can be easily modified when new metrics are created, and it illustrates the use of WL and its associated highway safety implications. In short, the approach is based on common sense with trained engineering experience and logic integrated into data-driven safety analyses. The example is a continuation of an earlier FHWA research study illustrating the application of road safety audits and the Interactive Highway Safety Design Model (IHSDM). The IHSDM, Excel, and Google Earth were used because no funding was available for on-road data collection.
Highway functional classifications (FCs) were first created in the Federal-Aid Act of 1921. The purpose of FC of highways is to ensure that national and state highway systems provide both mobility ...and accessibility for the public. The system created has worked reasonably well over the course of the last 100 years. But problems are occurring and it is time to consider new ways to implement road classification systems. The 1921 legislation established a national system of highways which included a federal aid and primary system for the United States. The national system has greatly enhanced users’ ability to travel long distances by land and to move products from the factory and farm to customers throughout the U.S. much more quickly and cheaply than before. But times have changed and economic growth is being threatened by delays in adding to, improving, and modifying the 3.5 million mi highway network. Both urban and rural daily traffic delays are common. Modification and changing FC of roads take years to finalize. Progress must be improved for continued national transportation success, local growth, and world competitiveness. But even with the willingness to make enhancements in how FCs are managed and modernized, the question is, can the U.S. continue its national economic success? This article will describe two recommendations that if implemented will ensure continued transportation growth and success while taking into account the needs of users at all road levels.
Vision Zero (VZ) and infrastructure-user errors (IUE) have been discussed in the United States for years, but we still have more than 35,000 fatalities per year. In implementing both VZ and IUE, the ...United States has used a top-down approach where federal, state, and local governments have joined with private organizations like American Association of State Highway and Transportation Officials (AASHTO), National Safety Council (NSC), and others to promote highway transportation safety with a goal of zero fatalities within by 2050.2 Unfortunately, neither the VZ nor IUE goals have ever been successively pursued and the improved safety levels keep slipping further into the future. So what is the problem? Will we ever be able to achieve a significant decrease in road fatalities? Apparently, we need to modify our approach. The objective of this paper is to present 10 examples of VZ and IUE problems appropriate for a bottom-up type of project selection. We are not addressing the merits of how funds and projects are approved, but instead present examples of potential small, relatively inexpensive VZ and IUE projects that are often overlooked but are nevertheless part of the safety problem.
There are now two highway transportation engineering tools available to highway designers, highway planners, and traffic engineers to help identify driver behavior problems and then select ...appropriate safety treatments. They are the American Association of State Highway and Transportation Officials' (AASHTO) Highway Safety Manual (HSM) and the Transportation Research Board's (TRB) Human Factors Guidelines for Road Systems (HFG). The HSM may be used to quantify the effects of safety decision-making on crash frequency and severity outcomes when estimating the safety of roadway infrastructure projects. At their inception, the HSM and HFG were envisioned to be living documents that would incorporate new research as it became available. The HSM would focus on improved safety quantitative estimating methodologies and the HFG would focus on road user human factor research as it became available for guideline material. It was recognized that some topics could not be developed in the initial HFG publication. It is expected the upcoming 3rd edition of the HFG will contain chapters for bicycles, motorcycles, roundabouts, and more pedestrian guidelines.
Since 1941 the Bureau of Public Roads has conducted a research program to determine periodically the braking performance levels of motor vehicles operating on public highways. The research is used to ...promote improvement in the general level of brake performance for all types of vehicles, provide information that may be used in establishing highway design standards, and serve as a basis for revising brake performance standards. The most recent study was completed in November 1963. It was explained to each driver that the tests were voluntary and no punitive action would be taken regardless of the condition of the vehicle brakes. The results of the study indicated that the braking performance has generally improved regardless of vehicle type, weight, or capacity.
This study investigates the relationship between the gross weight and net engine horsepower of commercial vehicles. The data were used to update current information on weight-power ratios of trucks ...and investigate the trend in the ratios since 1949. There is a definite increase in the weight-power ratio as the number of axles increases, regardless of vehicle type. There is also an overall trend to lower weight-power ratios as evidenced by a 12% reduction in the ratio from 1949 to 1955 and a further reduction of 28% from 1955 to 1963. A performance requirement of 400 lb/hp is liberal and would affect only a small percentage of the total trucks.
Innovative traffic control practices in Europe HAWKINS, H.G. JR; WAIN WRIGHT, W.S; TIGNOR, S.C
Public Roads,
09/1999, Letnik:
63, Številka:
2
Magazine Article, Trade Publication Article
Vehicular travel is increasing throughout the world, particularly in large urban areas. Accomodating the increased demand, while improving traffic safety, has led transportation officials to use a ...variety of innovative traffic control practices. The traffic control practices in Europe are discussed.
