Eugene R. Russell

Setting Speed Limits on Kansas Two-Lane Highways: Neuronet Approach

Recent federal legislation allowing states to set their own speed limits on highways, as well as increases in the number of requests from citizens and neighborhood groups to implement actions to reduce “excessive” speeding on their streets and highways, has created considerable debate about and scrutiny of the appropriate speed limits that should be posted on state highways. Various speed studies have indicated that sensible and cautious drivers will most likely drive at the speed dictated by roadway and traffic conditions rather than relying on a posted speed limit. To incorporate roadway characteristics and traffic volumes into the selection of the most appropriate (i.e., comfortable, safe, and efficient) speed limit, actual engineering field speed studies are carried out. Generally, the 85th percentile speed at which the drivers surveyed are driving is selected as a primary factor in determining the posted speed limit. Carrying out such field studies for all highway sections is a costly and time-consuming process. Therefore, characterizing the relationship between the 85th percentile speed and the roadway characteristics will assist in selecting the most appropriate posted speed limit on highway sections where field surveying is difficult due to resource limitations. A back-propagation neural network is used to extract the relationship between roadway characteristics and 85th percentile speed. The developed neural-network-based speed model was found to perform satisfactorily for characterization of speed on Kansas two-lane, uninterrupted-flow rural highways and for quantifying the influence of prevailing roadway characteristics on the anticipated 85th percentile speed.

Centerline Rumble Strips: Study of External Noise

Centerline rumble strips (CLRS) are patterns installed on the center of undivided, two-lane highways. Their main function is to alert drivers by producing noise and vibration. This treatment has been demonstrated to be effective in reducing crossover crashes. However, there are some disadvantages in their utilization, such as the exterior noise created by the strips. The objectives of this study were to quantify the levels of exterior noise; to verify the effects of speed, vehicle, CLRS shape, and distance on exterior noise; and to investigate the amount of noise created by CLRS that affects roadside residences and businesses. Two types of vehicles [2006 Ford Taurus (sedan) and 2008 Chevrolet Express (15 passenger van)] were driven over two different patterns of milled-in CLRS and over smooth asphalt pavement at two different speeds. Researchers collected the noise levels at three distances from the road at 10 different locations. Results indicated that vehicle type, speed, CLRS presence, and distance affect exterior noise levels. CLRS noise levels were statistically greater than smooth pavement noise levels, and the difference would be perceived by human ears at distances up to 45 meters.

LOW-VOLUME ROADS AND THE GRADE CROSSING PROBLEM

Summarized are problems associated with low-volume road (LVR) passive grade crossings, low-cost innovative devices that have been developed and tested to improve safety, policies, and programs that have been developed and promoted in the United States to enhance safety at LVR grade crossings, particularly at night. On the basis of safety studies and years of experience, conclusions and recommendations are presented to reduce drivers’ risk at the typical passive, rail-highway grade crossing found on LVRs. Stressed are the two keys to reducing risk at LVR, passive grade crossings: provide adequate sight distance and make the crossing and warning devices conspicuous, particularly at night.

LOCATION AND CONFIGURATION OF PASSING LANES

Kansas State University conducted a study of passing lanes on major two-lane highways in Kansas. Passing lane location and configuration are among the crucial design factors that may affect the operation and safety of two-lane highways containing passing lanes. The literature suggests that passing lanes should not be located where crossroad intersections exist. Yet a traffic conflict study of Kansas passing lane locations found that the mean traffic conflict level at crossroad intersections located within the passing lane was lower than it was at a similar intersection on a two-lane highway outside the passing lane sections. Crossroad intersections may be tolerated within passing lanes if they are not in the laneaddition and lane-drop areas of the passing lane and if turning volumes are relatively low. Based on traffic simulation, there was no evidence that tail-to-tail passing lane configurations are better than other configurations, as claimed in the literature. However, the difference in percent time delay between different passing lane configurations was found marginal from a practical point of view.

Drivers' Attitudes, Understanding, and Acceptance of Passing Lanes in Kansas

Traditionally, highway improvement project evaluation is done without incorporating highway users’ views. The Kansas Department of Transportation (KDOT) wants drivers to be satisfied and have “good feelings” about its passing lanes program. KDOT needs input to decide whether passing lanes are efficient, safe, and acceptable to the public. Drivers’ views were solicited via a questionnaire survey which was part of a comprehensive study on passing lanes in Kansas. Generally, drivers support the passing lane program and suggest construction of more passing lanes. Drivers think that passing lanes are more beneficial for improving safety than for saving time. They are equally divided on the length of passing lanes between “too short” and “just right,” although the provided lengths are within the recommended optimum lengths found in the literature. The “too short” responses could be due to existing passing lane spacings, preference of four-lane highways over two-lane highways, and difference in local conditions from those used to determine lengths. Drivers cited fellow drivers’ failure to follow signs and markings properly, and failure to use the lanes properly; this seems to indicate that improvements in signing and pavement markings should be considered. A smaller proportion of drivers, satisfied with a lower frequency of local travel on a route closer to the state’s borders (i.e., more unfamiliar drivers), suggests the importance of standardizing highway operating and design practices throughout the country.

Incorporating Robustness Analysis into Urban Transportation Planning Process

When developing a regional transportation plan (RTP), growth assumptions are made for socioeconomic factors such as population, housing, and employment for a future planning horizon. In turn, these factors become the basis of projecting future transportation networks, streets, highways, transit loadings, and the resulting traffic flows. Like any future forecasting, these assumptions are bound to contain some errors.

Safety Effectiveness of Centerline Rumble Strips in Kansas

The occurrence of roadway departure crashes is a serious problem in the United States. These types of crashes correspond to approximately 40% of all crashes in the United States, and their estimated annual cost is

RAIL-HIGHWAY GRADE CROSSING CONSOLIDATION IN KANSAS

100 billion. The objective of this study was to quantify the safety effectiveness of center line rumble strips (CLRS) in Kansas. CLRS are raised or grooved patterns installed on the center of two-lane, undivided, rural highways to prevent mainly cross-over crashes, more specifically head-on and sideswipe in opposite direction types of crashes. In this study, 29 sections of highways with two patterns of CLRS (rectangular and football) were analyzed, totaling more than 590 km. The naïve and the empirical Bayes before-and-after methods were applied and compared. Results showed that following the installation of CLRS, total crashes judged to be correctable by CLRS were reduced by approximately 29%. Correctable crashes involving fatalities and injuries were reduced by approximately 34%. Cross-over crashes were reduced by approximately 67%. Run-off-the-road crashes were reduced by 19%. All comparisons except for run-off-the-road crashes were statistically significant. The two methods applied presented statistically similar results. There was no statistical differences between results from sections with rectangular or football shaped CLRS.

Life-Cycle Economic Comparison of Common Signpost Materials and Types

Consolidation or closure of unnecessary grade crossings is a cost-effective but difficult-to-achieve option for increasing the safety of highway-rail grade crossings. Consolidation not only needs traffic engineering expertise, it also needs the support of local government officials and citizens. It is as much a public relations effort as an engineering exercise. To win local support, proposals for closing selected crossings should appear reasonable to the public, that is, the public should be able to see a need or net benefit. A corridor study is more effective than targeting single crossings for closure. Selecting a corridor with high-potential closure candidates can be the key to the success of winning local approval. Finding the most “hazardous” crossings can help select high-potential corridors. The development of a model to pinpoint Kansas’ best candidates for closure as a key step in selecting corridors where consolidation efforts should be concentrated is described.

Procedure for Developing Truck Accident and Release Rates for Hazmat Routing

There is a wealth of information related to life-cycle costs of different sign sheeting materials and considerable information on common signposts, but there is little or no information about the life-cycle costs of different types of signposts. The primary objective of this research was to determine the best cost-effective policy, consistent with safety, for signpost materials and types used on state highways in Kansas. From the initial literature review, a matrix was constructed detailing the various materials used for signposts by each state. This was followed with a survey questionnaire to gather information on what posts other states were using for three major types of signs used in Kansas. From the data obtained from the state departments of transportation, test installations were carried out by three vendors. Life-cycle economic analysis was conducted, taking into consideration the labor, equipment, and time requirements for the initial installation and the replacement. Among the four systems compa...